R. P. Ray

7402180930

Publications - 65

Sensitivity analysis and optimization of pier shape scour prediction using HEC-RAS

Muhanad Al-Jubouri Ethar H. Abbas R. P. Ray

Publication Name: Pollack Periodica

Publication Date: 2025-06-27

Volume: 20

Issue: 2

Page Range: 8-15

Description:

Scour around bridge piers threatens bridge stability. This study uses the Hydrologic Engineering Center River Analysis System to improve depth estimates for various pier shapes. The Colorado State University and Froehlich equations were tested with a one-dimensional model calibrated for circular, square, rectangular, oblong, oval, and cylindrical piers. Sensitivity analysis identified coefficients K2, K3, flow velocity, and depth as key factors, with K2 being most significant. The Colorado State University equation overestimated scour depths, especially for square piers. The Froehlich method provided more accurate predictions, confirming the system’s value in hydraulic modeling for bridge stability analysis.

Open Access: Yes

DOI: 10.1556/606.2024.01211

Application of Decision Support Systems to Water Management: The Case of Iraq

Katalin Bene Nasrat Adamo Hayder Thabit Al Hudaib Nadhir Al-Ansari R. P. Ray

Publication Name: Water Switzerland

Publication Date: 2025-06-01

Volume: 17

Issue: 12

Page Range: Unknown

Description:

Iraq has faced escalating water scarcity over the past two decades, driven by climate change, upstream water withdrawals, and prolonged economic instability. These factors have caused deterioration in irrigation systems, inefficient water distribution, and growing social unrest. As per capita water availability falls below critical levels, Iraq is entering a period of acute water stress. This escalating water scarcity directly impacts water and food security, public health, and economic stability. This study aims to develop a general framework combining decision support systems (DSSs) with Integrated Comprehensive Water Management Strategies (ICWMSs) to support water planning, allocation, and response to ongoing water scarcity and reductions in Iraq. Implementing such a system is essential for Iraq to alleviate its continuing severe situation and adequately tackle its worsening water scarcity that has intensified over the years. This integrated approach is fundamental for enhancing planning efficiency, improving operational performance and monitoring, optimizing water allocation, and guiding informed policy decisions under scarcity and uncertainty. The current study highlights various international case studies that show that DSSs integrate real-time data, artificial intelligence, and advanced modeling to provide actionable policies for water management. Implementing such a framework is crucial for Iraq to mitigate this critical situation and effectively address the escalating water scarcity. Furthermore, Iraq’s water management system requires modifications considering present and expected future challenges. This study analyzes the inflows of the Tigris and Euphrates rivers from 1933 to 2022, revealing significant reductions in water flow: a 31% decrease in the Tigris and a 49.5% decline in the Euphrates by 2021. This study highlights the future 7–20% water deficit between 2020 and 2035. Furthermore, this study introduces a flexible, tool-based framework supported by a DSS with the DPSIR model (Driving Forces, Pressures, State, Impacts, and Responses) designed to address and reduce the gap between water availability and increasing demand. This approach proposes a multi-hazard risk matrix to identify and prioritize strategic risks facing Iraq’s water sector. This matrix links each hazard with appropriate DSS-based response measures and supports scenario planning under the ICWMS framework. The proposed framework integrates hydro-meteorological data analysis with hydrological simulation models and long-term investment strategies. It also emphasizes the development of institutional frameworks, the promotion of water diplomacy, and the establishment of transboundary water allocation and operational policy agreements. Efforts to enhance national security and regional stability among riparian countries complement these actions to tackle water scarcity effectively. Simultaneously, this framework offers a practical guideline for water managers to adopt the best management policies without bias or discrimination between stakeholders. By addressing the combined impacts of anthropogenic and climate change, the proposed framework aims to ensure rational water allocation, enhance resilience, and secure Iraq’s water strategies, ensuring sustainability for future generations.

Open Access: Yes

DOI: 10.3390/w17121748

Comparing Depth-Integrated Models to Compute Overland Flow in Steep-Sloped Watersheds

Katalin Bene Gergely Ámon R. P. Ray

Publication Name: Hydrology

Publication Date: 2025-04-01

Volume: 12

Issue: 4

Page Range: Unknown

Description:

On steep-sloped watersheds, high-intensity, short-duration rainfall events are the leading causes of flash floods. Typical overland flow analysis assumes sheet-like flow with a shallow water depth. However, the natural creek beds in steep watersheds produce complex and intense flows with a shallow depth and high velocity. According to the hydrodynamical modeling processes for open channel turbulent flow, calculating rainfall-induced overland flow becomes a complex task. Steep topography requires a highly refined numerical mesh, which demands a more complex simulation process. Depth-integrated models with distributed parameters provide useful methods to capture the behavior of steep watersheds. This study investigates the watershed’s overland flow behavior by varying turbulent flow parameters and monitoring possible model errors. The refined modeling places a heavy demand on numerical solvers used for simulating the overland flow motion. This paper examines different depth-integrated model solvers applied to artificial watersheds and compares results produced by the different solver types. This study found that the Shallow Water Equation solutions produced the most consistent and stable results, with the Local Inertia Approximation solutions performing adequately. Adding Large Eddy Simulation to these solutions tended to overcomplicate Shallow Water solutions but generally improved Large Eddy solutions. The Diffuse Wave Equation solutions produced erratic results, losing stability and accuracy as watershed slopes steepened and flow paths became complex.

Open Access: Yes

DOI: 10.3390/hydrology12040067

Relationships between Shear Strength Parameters with Mineralogy and Index Properties of Compacted, Unsaturated Soils

Elizabeth Theron Sai K. Vanapalli Armand Augustin Fondjo R. P. Ray

Publication Name: Studia Geotechnica Et Mechanica

Publication Date: 2025-03-01

Volume: 47

Issue: 1

Page Range: 65-88

Description:

The objective of this study is to assess the influences of soil index properties, swelling parameters, and soil mineralogy on unsaturated shear strength parameters (φ', φb, c') of compacted expansive soils. The laboratory tests include the grain size distribution, specific gravity (Gs), Atterberg limits, swelling potential, X-ray diffraction, modified Proctor compaction, soil suction, and triaxial testing. MINITAB 19 statistical analysis software generates the tri-dimensional surface graphs. The values φ', φb, and c"are majorly influenced by water (%), Gs, and clay (%). φ"shows a strong correlation with free swell ratio (FSR), free swell index (FSI), and void ratio. φb demonstrates a strong relationship with liquid limit, plasticity index, and γd (dry unit weight). φ"and c"portray a moderate relationship with liquid limit, plasticity limit, and γd. φ"exhibits a moderate correlation with smectite (%) and plagioclase (%). φb describes a strong relationship with smectite (%) and a moderate correlation with plagioclase and K-feldspar (%). c"depicts a moderate correlation with smectite (%), K-feldspar (%), and plagioclase (%). The matric suction controls the behaviour of unsaturated soils. Nonetheless, the influences of soil index properties, swelling potential, and mineralogy on shear strength are not marginal. These findings provide a good insight into the behaviour of unsaturated expansive soils and contribute to enhancing geotechnical modelling.

Open Access: Yes

DOI: 10.2478/sgem-2025-0006

Uncertainty Quantification in Shear Wave Velocity Predictions: Integrating Explainable Machine Learning and Bayesian Inference

Ayele Chala R. P. Ray

Publication Name: Applied Sciences Switzerland

Publication Date: 2025-02-01

Volume: 15

Issue: 3

Page Range: Unknown

Description:

The accurate prediction of shear wave velocity (Vs) is critical for earthquake engineering applications. However, the prediction is inevitably influenced by geotechnical variability and various sources of uncertainty. This paper investigates the effectiveness of integrating explainable machine learning (ML) model and Bayesian generalized linear model (GLM) to enhance both predictive accuracy and uncertainty quantification in Vs prediction. The study utilizes an Extreme Gradient Boosting (XGBoost) algorithm coupled with Shapley Additive Explanations (SHAPs) and partial dependency analysis to identify key geotechnical parameters influencing Vs predictions. Additionally, a Bayesian GLM is developed to explicitly account for uncertainties arising from geotechnical variability. The effectiveness and predictive performance of the proposed models were validated through comparison with real case scenarios. The results highlight the unique advantages of each model. The XGBoost model demonstrates good predictive performance, achieving high coefficient of determination ((Formula presented.)), index of agreement (IA), Kling–Gupta efficiency (KGE) values, and low error values while effectively explaining the impact of input parameters on Vs. In contrast, the Bayesian GLM provides probabilistic predictions with 95% credible intervals, capturing the uncertainty associated with the predictions. The integration of these two approaches creates a comprehensive framework that combines the strengths of high-accuracy ML predictions with the uncertainty quantification of Bayesian inference. This hybrid methodology offers a powerful and interpretable tool for Vs prediction, providing engineers with the confidence to make informed decisions.

Open Access: Yes

DOI: 10.3390/app15031409

Efficient Uncertainty Quantification in Seismic Site Response via Random Field Modeling

Ayele Chala R. P. Ray

Publication Name: Geotechnical Special Publication

Publication Date: 2025-01-01

Volume: 2025-March

Issue: GSP 366

Page Range: 158-169

Description:

Assessing seismic site response with absolute certainty remains challenging due to inherent soil variabilities. Soil variabilities primarily stem from natural geologic processes and lie beyond human control. Soil characteristics, including shear wave velocity, shear modulus, unit weight, and plasticity, exhibit inherent randomness and variability. These factors significantly influence seismic site responses, making it crucial to account for parameter uncertainty in seismic behavior characterization. Precisely characterizing this uncertainty is essential for reliable seismic hazard assessment and the design of earthquake-resistant structures. However, this task faces challenges due to the computational expense associated with many model realizations. In this study, a computationally efficient and user-friendly model for estimating peak ground acceleration (PGA), displacement (PGD), and quantifying uncertainty was developed. The methodology comprises two main steps: (1) 2D equivalent linear seismic site response analyses were simulated using MIDAS GTS NX commercial software. These simulations incorporated randomly generated properties of clay soil, including maximum shear modulus (G0), unit weight (γ), and plasticity index (PI). (2) Leveraging data from the site response analyses, a Bayesian regression model was developed using the R programming language. The accuracy and reliability of the developed model were validated using a new data set, and the results closely aligned with finite element method (FEM) outcomes. By accounting for soil inherent variabilities, the model effectively characterizes the uncertainty of PGA and PGD using mean and coefficient of variation (CoV). Remarkably, the Bayesian approach yielded CoV of response parameters up to 2.33%, a substantial 94.37% relative difference compared to the FEM. Notably, this improvement in uncertainty was achieved while maintaining computational efficiency.

Open Access: Yes

DOI: 10.1061/9780784485996.016

Quantifying Geotechnical Uncertainty in Ground Motion Predictions: Bayesian Generalized Linear Model Framework

Clara Beatrice Vilceanu Ayele Chala Mais Mayassah R. P. Ray

Publication Name: Advances in Civil Engineering

Publication Date: 2025-01-01

Volume: 2025

Issue: 1

Page Range: Unknown

Description:

Accurate prediction of peak ground intensity measures is inevitably influenced by geotechnical variability. Variations in soil properties, subsurface conditions, and seismic inputs introduce complexities that challenge the reliability of predictions. This study introduces a Bayesian generalized linear model (GLM) to probabilistically predict peak ground acceleration (PGA) while accounting for uncertainties associated with geotechnical variability. Latin hypercube sampling (LHS) was employed to generate synthetic datasets of key geotechnical parameters, including plasticity index, shear wave velocity, soil thickness, input motion intensity, and unit weight of soil for hypothetical sites. Subsequently, a series of one-dimensional equivalent linear (1D-EQL) seismic site response analyses were performed, and PGA value at ground surface level were recorded for each analysis. The Bayesian GLM was then developed using these comprehensive datasets to probabilistically predict PGA. The performance and reliability of the developed model were evaluated on a separate test dataset. To benchmark its performance, a Bayesian neural network (BNN) was also developed and compared. In addition, a Shiny-based graphical user interface (GUI), named Bayes-PGA-predictor, was implemented to facilitate practical application. The findings demonstrate that the Bayesian GLM offers a robust and interpretable approach to predicting PGA while effectively quantifying uncertainty associated with geotechnical variability.

Open Access: Yes

DOI: 10.1155/adce/6678669

Innovative wireless sensing for modal analysis and damage modeling of Petőfi Bridge

Rajmund Kuti M. Brinissat R. P. Ray

Publication Name: Results in Engineering

Publication Date: 2024-12-01

Volume: 24

Issue: Unknown

Page Range: Unknown

Description:

The historic Petőfi Bridge (1933), a steel truss structure in Győr, Hungary, exemplifies the vulnerability of truss-type bridges to both local and total collapse. This study introduces an innovative, low-cost, accurate, and scalable wireless sensing system (WSS) for Structural Health Monitoring (SHM), utilizing the Petőfi Bridge as a case study. The research details the architecture and workflow of the system, with experimental validations confirming the accuracy of measured acceleration responses. The main natural frequencies of the bridge were estimated by processing the collected data, showing a strong correlation with reference values obtained through conventional wired systems. A calibrated high-fidelity finite element model analyzed the sensitivity of bridge damage detection indicators. The study explores variations in vertical displacement, and modal frequencies, and validates an approach based on displacement influence lines (DILs). The findings indicate the varying efficacy of these indicators in detecting structural damage, providing critical insights for advancing SHM practices.

Open Access: Yes

DOI: 10.1016/j.rineng.2024.103527

Adaptive Exploration Artificial Bee Colony for Mathematical Optimization

Edina Koch Hazim Albedran Shaymaa Alsamia R. P. Ray

Publication Name: AI Switzerland

Publication Date: 2024-12-01

Volume: 5

Issue: 4

Page Range: 2218-2236

Description:

The artificial bee colony (ABC) algorithm is a famous swarm intelligence method utilized across various disciplines due to its robustness. However, it exhibits limitations in exploration mechanisms, particularly in high-dimensional or complex landscapes. This article introduces the adaptive exploration artificial bee colony (AEABC), a novel variant that reinspires the ABC algorithm based on real-world phenomena. AEABC incorporates new distance-based parameters and mechanisms to correct the original design, enhancing its robustness. The performance of AEABC was evaluated against 33 state-of-the-art metaheuristics across twenty-five benchmark functions and an engineering application. AEABC consistently outperformed its counterparts, demonstrating superior efficiency and accuracy. In a variable-sized problem (n = 10), the traditional ABC algorithm converged to 3.086 × 106, while AEABC achieved a convergence of 2.0596 × 10−255, highlighting its robust performance. By addressing the shortcomings of the traditional ABC algorithm, AEABC significantly advances mathematical optimization, especially in engineering applications. This work underscores the significance of the inspiration of the traditional ABC algorithm in enhancing the capabilities of swarm intelligence.

Open Access: Yes

DOI: 10.3390/ai5040109

Prediction of Scour Depth for Diverse Pier Shapes Utilizing Two-Dimensional Hydraulic Engineering Center’s River Analysis System Sediment Model

Muhanad Al-Jubouri Ethar H. Abbas R. P. Ray

Publication Name: Fluids

Publication Date: 2024-11-01

Volume: 9

Issue: 11

Page Range: Unknown

Description:

Examining scouring around bridge piers is crucial for ensuring water-related infrastructure’s long-term safety and stability. Accurate forecasting models are essential for addressing scour, especially in complex water systems where traditional methods fall short. This study investigates the application of the HEC-RAS 2D sedimentation model, which has recently become available for detailed sediment analysis, to evaluate its effectiveness in predicting scoring around various pier shapes and under different water conditions. This study offers a comprehensive assessment of the model’s predictive capabilities by focusing on variables such as water velocity, shear stress, and riverbed changes. Particular attention was paid to the influence of factors like floating debris and different pier geometries on scour predictions. The results demonstrate that while the HEC-RAS 2D model generally provides accurate predictions for simpler pier shapes—achieving up to 85% precision—it shows varied performance for more complex designs and debris-influenced scenarios. Specifically, the model overpredicted scouring depths by approximately 20% for diamond-shaped piers and underpredicted by 15% for square piers in debris conditions. Elliptical piers, in contrast, experienced significantly less erosion, with scour depths up to 30% shallower compared to other shapes. This study highlights the novel application of the HEC-RAS 2D model in this context and underscores its strengths and limitations. Identified issues include difficulties in modeling water flow and debris-induced bottlenecks. This research points to the improved calibration of sediment movement parameters and the development of advanced computational techniques to enhance scour prediction accuracy in complex environments. This work contributes valuable insights for future research and practical applications in civil engineering, especially where traditional scour mitigation methods, such as apron coverings, are not feasible.

Open Access: Yes

DOI: 10.3390/fluids9110247

Comparative Analysis of Foundation Systems in Expansive Soil: A Three-Dimensional Model Approach to Moisture Diffusion and Volume Changes

Ammar N. Alnmr Mounzer Omran Alzawi R. P. Ray

Publication Name: Geotechnical and Geological Engineering

Publication Date: 2024-11-01

Volume: 42

Issue: 8

Page Range: 7935-7961

Description:

This study compares the performance of various foundation systems in expansive soils, such as mats, granular anchor piles, and concrete piles. Expansive soils experience volumetric changes due to moisture fluctuations, which can lead to structural damage. Abaqus software, in conjunction with the SCV approach, is used to analyze soil-foundation interactions. A custom subroutine enhances simulation accuracy by incorporating empirical data on unsaturated clay behavior, matric suction, and variations in effective stress. The method’s accuracy is validated by comparing simulation results to field and laboratory experiments. The findings indicate that increasing the applied load on mats decreases overall heave but increases the differential heave. Additionally, higher soil permeability dereases the differential heave of mats. Granular anchor piles outperform concrete piles by more than 50% in highly expansive soils, suggesting a preference for these foundations. This study provides insights into the behavior of expansive soils, which will assist engineers in designing resilient foundation systems for structures.

Open Access: Yes

DOI: 10.1007/s10706-024-02959-2

Advanced Numerical Simulation of Scour around Bridge Piers: Effects of Pier Geometry and Debris on Scour Depth

Muhanad Al-Jubouri Ethar H. Abbas R. P. Ray

Publication Name: Journal of Marine Science and Engineering

Publication Date: 2024-09-01

Volume: 12

Issue: 9

Page Range: Unknown

Description:

Investigating different pier shapes and debris Finteractions in scour patterns is vital for understanding the risks to bridge stability. This study investigates the impact of different shapes of pier and debris interactions on scour patterns using numerical simulations with flow-3D and controlled laboratory experiments. The model setup is rigorously calibrated against a physical flume experiment, incorporating a steady-state flow as the initial condition for sediment transport simulations. The Fractional Area/Volume Obstacle Representation (FAVOR) technique and the renormalized group (RNG) turbulence model enhance the simulation’s precision. The numerical results indicate that pier geometry is a critical factor influencing the scour depth. Among the tested shapes, square piers exhibit the most severe scour, with depths reaching 5.8 cm, while lenticular piers show the least scour, with a maximum depth of 2.5 cm. The study also highlights the role of horseshoe, wake, and shear layer vortices in determining scour locations, with varying impacts across different pier shapes. The Q-criterion study identified debris-induced vortex generation and intensification. The debris amount, thickness, and pier diameter (T/Y) significantly affect the scouring patterns. When dealing with high wedge (HW) debris, square piers have the largest scour depth at T/Y = 0.25, while lenticular piers exhibit a lower scour. When debris is present, the scour depth rises at T/Y = 0.5. Depending on the form of the debris, a significant fluctuation of up to 5 cm was reported. There are difficulties in precisely estimating the scour depth under complicated circumstances because of the disparity between numerical simulations and actual data, which varies from 6% for square piers with a debris relative thickness T/Y = 0.25 to 32% for cylindrical piers with T/Y = 0.5. The study demonstrates that while flow-3D simulations align reasonably well with the experimental data under a low debris impact, discrepancies increase with more complex debris interactions and higher submersion depths, particularly for cylindrical piers. The novelty of this work lies in its comprehensive approach to evaluating the effects of different pier shapes and debris interactions on scour patterns, offering new insights into the effectiveness of flow-3D simulations in predicting the scour patterns under varying conditions.

Open Access: Yes

DOI: 10.3390/jmse12091637

Compressibility of expansive soil mixed with sand and its correlation to index properties

Rashad Alsirawan Ammar N. Alnmr Mounzer Omran Alzawi R. P. Ray

Publication Name: Heliyon

Publication Date: 2024-08-15

Volume: 10

Issue: 15

Page Range: Unknown

Description:

Prior research has primarily focused on Atterberg limits, void ratios, and/or water content, often disregarding the impact of coarse material percentage in the soil, which significantly affects compressibility behavior. This paper examines the effects of sand content, initial degree of saturation, and initial dry unit weight on the compressibility behavior of expansive soils. Ninty-six oedometer tests were performed in order to accurately predict the compressibility behavior of expansive soils. The previous studies have attempted to correlate compressibility with different index properties separately, but no single study has taken into consideration all properties influencing compressibility behavior, especially for expansive soils. The findings show that compressibility is greatly influenced by the sand content, initial degree of saturation, and initial dry unit weight. Increasing the initial dry unit weight specifically lowers the compression index and permeability while raising the recompression index for the same percentage of added sand. Moreover, since swelling reduces with increasing initial saturation, raising the saturation degree also lowers the permeability, recompression index, and compression index. The results indicate that a sand content of more than 30 % is recommended for achieving desired properties in expansive clayey soil. This is a result of sand taking the dominant role in the soil mixture, which lowers soil suction and improves soil properties by reducing swelling, permeability, and compressibility. Symbolic regression equations were created to predict the compression and recompression indices, outperforming previous models in accurately predicting the compressibility behavior of expansive soils, considering the percentage of sand. The validation of these equations demonstrates their predictive capabilities.

Open Access: Yes

DOI: 10.1016/j.heliyon.2024.e35711

Prioritising water-related regional development project ideas based on stakeholder involvement activities: A case study from Szigetköz, Hungary

Katalin Bene Máté Chappon Attila Kálmán R. P. Ray

Publication Name: Environmental Challenges

Publication Date: 2024-08-01

Volume: 16

Issue: Unknown

Page Range: Unknown

Description:

Szigetköz—a large island of the Danube in Hungary—is attracting a new wave of interest in water-related regional development projects from the public and private sectors alike. The revived interest in the Szigetköz floodplain area, which has historically endured the adverse effects of large-scale water management initiatives, draws attention to the necessity for careful consideration and the active involvement of local stakeholders in the decision-making process. In our research, we conducted various stakeholder engagement activities, including interviews, questionnaires, and workshops. These activities helped define the problems and objectives of each stakeholder group. Through collaborative consultations, we gathered over 100 proposed water related development project ideas. Additionally, to address key issues in project development and selection, we evaluated the integrative potential of each proposed project, considering the number of distinct water management issues it addressed. We also assigned an attitude score to each project, derived from the diverse objectives of various stakeholder groups, and analysed these quantities using a multiple-criteria analysis. This paper details a novel approach to assess and rank the proposed water-related regional development project ideas based on the calculated integrative potential and attitude scores. The goal was to prioritise and further develop these proposed projects to benefit Szigetköz and its surrounding areas. Main results of the study have shown the average project scored between 0.33–0.50 in integrative potential out of a maximum of 1.00 For positive attitude score the average was between 0.28–0.43, out of a maximum of 1.00 while for the negative attitude score the average project scored between -0.14–0.00 out of a minimum of -1.00. The ranking of projects that was based on these scores, highlighted three types of proposed projects that need to be further developed in different ways. The top-ranked positive attitude integrative projects need cost-benefit calculations involving all ecosystem services to justify their economic sustainability. Top-ranked opposing attitude integrative projects need conflict resolution to be socially sustainable. Finally, project ideas that scored low on integrative potential need to be developed to make use of blue-green infrastructure, and circular economical advancements to foster their environmental sustainability.

Open Access: Yes

DOI: 10.1016/j.envc.2024.100994

Investigating the Impact of Varying Sand Content on the Physical Characteristics of Expansive Clay Soils from Syria

Ammar N. Alnmr R. P. Ray

Publication Name: Geotechnical and Geological Engineering

Publication Date: 2024-06-01

Volume: 42

Issue: 4

Page Range: 2675-2691

Description:

Expansive clayey soils often pose challenges for construction projects due to their low bearing capacity, swelling, and shrinkage properties. While previous research has explored additives to enhance these soils’ properties, the potential of sand remains underexplored. This study investigates the impact of varying sand percentages on expansive clayey soils’ consistency, compaction, and permeability. This study examines how adding different percentages of sand influences the physical properties of expansive clayey soils. Laboratory tests involved systematic testing of texture, compaction, and permeability. Findings reveal a notable improvement in the physical properties of the soil with the addition of sand. Results from the laboratory tests provided data for empirical equations that facilitate the prediction of soil properties based on the sand content. The enhancement in soil properties underscores the potential of sand as an additive for expansive clayey soils. The empirical equations presented here provide practical benefits to geotechnical engineers and practitioners engaged in construction projects involving these soils, offering them valuable insights into the benefits of sand additives to improve physical characteristics. The insights gained from this research hold promising prospects for improving construction practices and addressing the challenges associated with these soils.

Open Access: Yes

DOI: 10.1007/s10706-023-02698-w

Novel Insights in Soil Mechanics: Integrating Experimental Investigation with Machine Learning for Unconfined Compression Parameter Prediction of Expansive Soil

Chuangxin Lyu Haidar Hosamo Hosamo Ammar N. Alnmr Mounzer Omran Alzawi R. P. Ray

Publication Name: Applied Sciences Switzerland

Publication Date: 2024-06-01

Volume: 14

Issue: 11

Page Range: Unknown

Description:

This paper presents a novel application of machine learning models to clarify the intricate behaviors of expansive soils, focusing on the impact of sand content, saturation level, and dry density. Departing from conventional methods, this research utilizes a data-centric approach, employing a suite of sophisticated machine learning models to predict soil properties with remarkable precision. The inclusion of a 30% sand mixture is identified as a critical threshold for optimizing soil strength and stiffness, a finding that underscores the transformative potential of sand amendment in soil engineering. In a significant advancement, the study benchmarks the predictive power of several models including extreme gradient boosting (XGBoost), gradient boosting regression (GBR), random forest regression (RFR), decision tree regression (DTR), support vector regression (SVR), symbolic regression (SR), and artificial neural networks (ANNs and proposed ANN-GMDH). Symbolic regression equations have been developed to predict the elasticity modulus and unconfined compressive strength of the investigated expansive soil. Despite the complex behaviors of expansive soil, the trained models allow for optimally predicting the values of unconfined compressive parameters. As a result, this paper provides for the first time a reliable and simply applicable approach for estimating the unconfined compressive parameters of expansive soils. The proposed ANN-GMDH model emerges as the pre-eminent model, demonstrating exceptional accuracy with the best metrics. These results not only highlight the ANN’s superior performance but also mark this study as a groundbreaking endeavor in the application of machine learning to soil behavior prediction, setting a new benchmark in the field.

Open Access: Yes

DOI: 10.3390/app14114819

Hydrodynamic Modeling and Comprehensive Assessment of Pier Scour Depth and Rate Induced by Wood Debris Accumulation

Muhanad Al-Jubouri R. P. Ray

Publication Name: Hydrology

Publication Date: 2024-04-01

Volume: 11

Issue: 4

Page Range: Unknown

Description:

This study mainly investigates the impact of debris accumulation on scour depth and scour hole characteristics around bridge piers. Through controlled experiments with uniform sand bed material, the influence of various debris shapes (high wedge, low wedge, triangle yield, rectangular, triangle bow, and half-cylinder), upstream debris length, downstream debris extension, and debris thickness on scour depth and scour hole area and volume around the cylindrical pier were analyzed. The findings revealed that the shape and location of debris in the water column upstream of piers are key factors that determine the depth of scour, with high wedge shapes inducing the deepest scour and potentially the largest scour hole, particularly when positioned close to the pier and fully submerged. Scenarios in which triangle bow debris was submerged at full depth upstream of the pier closely resembled situations devoid of debris. Conversely, debris extension downstream of the pier was found to reduce local scour depth while concurrently enlarging the dimensions of the scour hole. The existing scour prediction equations tend to overestimate scour depth in scenarios involving debris, particularly when applying effective and equivalent pier width. This discrepancy arises because these equations were originally developed to predict scour depth around piers in the absence of debris. In response, a refined model for predicting scour induced by debris was proposed, integrating factors such as upstream debris length, downstream extension, obstruction percentage, and debris shape factor. This model demonstrated strong agreement with experimental data within the scope of this study and underwent further validation using additional experimental datasets from other research endeavors. In conclusion, this experimental study advances the comprehension of scour processes around cylindrical bridge piers, providing valuable insights into the role of debris characteristics and positioning.

Open Access: Yes

DOI: 10.3390/hydrology11040052

Effects of Local Soil Profiles on Seismic Site Response Analysis

Ayele Chala R. P. Ray

Publication Name: Periodica Polytechnica Civil Engineering

Publication Date: 2024-03-18

Volume: 68

Issue: 2

Page Range: 403-410

Description:

Local soil conditions play a significant role in the intensity variations of seismic waves during earthquakes. These variations can be either amplified or de-amplified depending on the specific soil conditions. This study aimed to assess the impact of different soil profiles on seismic site responses. The study considered four types of site profiles: sand (Sa), clay (Cl), sand overlying clay (SaCl), and clay overlying sand (ClSa) profiles. To simulate the ground motion, we selected seven sets of strong earthquake records from the European Strong-Motion Database. These records were selected according to Eurocode-8 with a peak ground acceleration (PGA) of 0.24 g, site class A using REXEL computer program. The records were then applied to the bedrock at a depth of 30 meters. Subsequently, a series of 1-D equivalent linear (EQL) response analyses were performed using the STRATA. Amplification factors (AFs) and surface acceleration time histories provided quantitative evaluations for our analysis results. The results demonstrated that site profiles with clay overlying bedrock (SaCl and Cl profiles) exhibited higher seismic amplification and peak ground acceleration in comparison to site profiles with sand overlying bedrock (Sa and ClSa profiles). The maximum median AF is calculated from the SaCl site profile, while the minimum median AF was calculated from the ClSa profile. The relative difference between the maximum and the minimum median AFs was about 33.7%. Based on these results, we can conclude that soft local soils have a pronounced effect on the amplification of seismic waves compared to stiff local soils.

Open Access: Yes

DOI: 10.3311/PPci.22148

Multi-Span Box Girder Bridge Sensitivity Analysis in Response to Damage Scenarios

Rajmund Kuti M. Brinissat R. P. Ray

Publication Name: Buildings

Publication Date: 2024-03-01

Volume: 14

Issue: 3

Page Range: Unknown

Description:

Due to their distinct features, including structural simplicity and exceptional load-carrying capacity, steel box girder bridges play a critical role in transportation networks. However, they are categorized as fracture-critical structures and face significant challenges. These challenges stem from the overloading and the relentless effects of corrosion and aging on critical structural components. As a result, these bridges require thorough inspections to ensure their safety and integrity. This paper introduces generalized approaches based on vibration-based structural health monitoring in response to this need. This approach assesses the condition of critical members in a steel girder bridge and evaluates their sensitivity to damage. A rigorous analytical evaluation demonstrated the effectiveness of the proposed approach in evaluating the Szapáry multi-span continuous highway bridge under various damage scenarios. This evaluation necessitates extensive vibration measurements, with piezoelectric sensors capturing ambient vibrations and developing detailed finite element models of the bridge to simulate the structural behavior accurately. The results obtained from this study showed that bridge frequencies are sufficiently sensitive for identifying significant fractures in long bridges. However, the mode shape results show a better resolution when compared to the frequency changes. The findings are usually sensitive enough to identify damage at the affected locations. Amplitude changes in the mode shape help determine the location of damage. The modal assurance criterion (MAC) served to identify damage as well. Finally, the results show a distinct pattern of frequency and mode shape variations for every damage scenario, which helps to identify the damage type, severity, and location along the bridge. The analysis results reported in this study serve as a reference benchmark for the Szapáry Bridge health monitoring.

Open Access: Yes

DOI: 10.3390/buildings14030667

Improving Flash Flood Hydrodynamic Simulations by Integrating Leaf Litter and Interception Processes in Steep-Sloped Natural Watersheds

Péter Kalicz Zoltán Gribovszki Katalin Bene Gergely Ámon R. P. Ray

Publication Name: Water Switzerland

Publication Date: 2024-03-01

Volume: 16

Issue: 5

Page Range: Unknown

Description:

More frequent high-intensity, short-duration rainfall events increase the risk of flash floods on steeply sloped watersheds. Where measured data are unavailable, numerical models emerge as valuable tools for predicting flash floods. Recent applications of various hydrological and hydrodynamic models to predict overland flow have highlighted the need for improved representations of the complex flow processes that are inherent in flash floods. This study aimed to identify an optimal modeling approach for characterizing leaf litter losses during flash floods. At a gauged watershed in the Hidegvíz Valley in Hungary, a physical-based model was calibrated using two distinct rainfall–runoff events. Two modeling methodologies were implemented, integrating canopy interception and leaf litter storage, to understand their contributions during flash flood events. The results from the model’s calibration demonstrated this approach’s effectiveness in determining the impact of leaf litter on steep-sloped watersheds. Soil parameters can estimate the behavior of leaf litter during flash flood events. In this study, hydraulic conductivity and initial water content emerged as critical factors for effective parametrization. The findings underscore the potential of a hydrodynamic model to explore the relationship between leaf litter and flash flood events, providing a framework for future studies in watershed management and risk-mitigation strategies.

Open Access: Yes

DOI: 10.3390/w16050750

Experimental Investigation of the Soil-Water Characteristic Curves (SWCC) of Expansive Soil: Effects of Sand Content, Initial Saturation, and Initial Dry Unit Weight

Safwan Abdullah Ammar N. Alnmr Jihad Ibraheem Mounzer Omran Alzawi R. P. Ray

Publication Name: Water Switzerland

Publication Date: 2024-03-01

Volume: 16

Issue: 5

Page Range: Unknown

Description:

Soil-water characteristic curve (SWCC) is an essential parameter in unsaturated soil mechanics, and it plays a significant role in geotechnical engineering to enhance theoretical analysis and numerical calculations. This study investigated the effects of key factors, such as the percentage of sand, initial degree of saturation, and initial dry unit weight, on the SWCC of expansive soil by measuring the matric suction using a pressure apparatus method. The empirical equation of SWCC was obtained using the Van Genuchten and Fredlung Xing models, and the processing of experimental data checks the fitting of the two empirical models. The findings revealed that the Fredlung Xing model fit the relationship between matric suction and volumetric water content of expansive soil better than the Van Genuchten model, indicating that the pressure apparatus approach’s experimental data are correct and acceptable. The study also found that the matric suction increased with decreasing percentage of added sand at the same volumetric moisture content, and the increase in initial dry unit weight increased the matric suction, with the water retention capacity decreasing significantly after adding 20% sand. Moreover, as the initial degree of saturation increased, the volumetric water content decreased, and the characteristic curves became identical when the initial saturation degree reached 90%. Finally, to minimize the water retention capacity of expansive soils, the study recommended adding a percentage of sand not less than 30% to the expansive clay sample.

Open Access: Yes

DOI: 10.3390/w16050627

A Novel Approach to Swell Mitigation: Machine-Learning-Powered Optimal Unit Weight and Stress Prediction in Expansive Soils

Ammar N. Alnmr Mounzer Omran Alzawi R. P. Ray

Publication Name: Applied Sciences Switzerland

Publication Date: 2024-02-01

Volume: 14

Issue: 4

Page Range: Unknown

Description:

Expansive soils pose significant challenges to structural integrity, primarily due to volumetric changes that can lead to detrimental consequences and substantial economic losses. This study delves into the intricate dynamics of expansive soils through loaded swelling pressure experiments conducted under diverse conditions, encompassing variations in the sand content, initial dry unit weight, and initial degree of saturation. The findings underscore the pronounced influence of these factors on soil swelling. To address these challenges, a novel method leveraging machine learning prediction models is introduced, offering an efficient and cost-effective framework to mitigate potential hazards associated with expansive soils. Employing advanced algorithms such as decision tree regression (DTR), random forest regression (RFR), gradient boosting regression (GBR), extreme gradient boosting (XGBoost), support vector regression (SVR), and artificial neural networks (ANN) in the Python software 3.11 environment, this study aims to predict the optimal applied stress and dry unit weight required for soil swelling mitigation. Results reveal that XGBoost and ANN stand out for their precision and superior metrics. While both performed well, ANN demonstrated exceptional consistency across training and testing phases, making it the preferred choice. In the tested dataset, ANN achieved the highest R-squared values (0.9917 and 0.9954), lowest RMSE (7.92 and 0.086), and lowest MAE (5.872 and 0.0488) for predicting optimal applied stress and dry unit weight, respectively.

Open Access: Yes

DOI: 10.3390/app14041411

Impact Assessment of Railway Bridge Construction Schedule, based on 3D Geotechnical Finite Element Modeling

Edina Koch R. P. Ray

Publication Name: Acta Polytechnica Hungarica

Publication Date: 2024-01-01

Volume: 21

Issue: 1

Page Range: 187-205

Description:

The increasing demand for high-speed railways has risen, to solve the "age-old" problem of bridge abutments, the step between the backfill and the bridge deck. Examples prove that inadequate technical solutions can generate damage that may require long-term speed restrictions or lead to short maintenance cycles, significantly increasing the total cost of ownership. The problems associated with the transition zones require complex analysis. The complex interaction of structural elements with different stiffnesses and different dynamic behavior varies over time due to the time-dependent behavior of the soil, and in addition, a bridge deck and its connecting elements can be constructed in several sequences. This study investigated a typical single-span railway bridge and its soil environment using PLAXIS 3D geotechnical finite element software. Different constitutive soil models were used to approximate the behavior of the bridge and the connecting elements. To model the soil behavior, the HS-small constitutive model was implemented. Loads of the structure are transferred onto the subsoil by 60 cm diameter piles modeled as embedded piles. Six different construction schedules were analyzed using time-domain analyses. The importance of high-speed railways was highlighted, and a 250 km/h train speed was applied, using dynamic analysis. The study focuses on the effect of different construction schedules on settlement, consolidation time, the behavior of the transition, and the substructure movements. The results of this study show that geotechnical approaches by themselves are not enough to solve the problem of the transition zone, highlighting the collaboration of geotechnical, structural and railway engineers.

Open Access: Yes

DOI: 10.12700/APH.21.1.2024.1.12

Enhancing pier local scour prediction in the presence of floating debris

Muhanad Al-Jubouri R. P. Ray

Publication Name: Pollack Periodica

Publication Date: 2024-01-01

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

Local scour poses a grave threat to bridge foundations, potentially causing catastrophic collapses. This study uses FLOW-3D with the Reynolds-Averaged Navier-Stokes model to analyze pier scour and dune formation under bridges. It focuses on submerged debris shapes near the water’s surface. Results closely match experiments when specific conditions are met. The study introduces an innovative approach to debris impact assessment. Instead of traditional methods, it proposes a novel equation accounting for debris’s effective area and elevation. This enhances reliability by over 20%, improving scour depth assessment in debris-laden scenarios. This advances the understanding of debris’s role in local scour, benefiting bridge design and management practices.

Open Access: Yes

DOI: 10.1556/606.2023.00952

Truck Load Positions Effect on Dynamic Behavior of Fractured Steel Box Girder Bridge

Rajmund Kuti M. Brinissat R. P. Ray

Publication Name: Advances in Transdisciplinary Engineering

Publication Date: 2024-01-01

Volume: 59

Issue: Unknown

Page Range: 67-74

Description:

The harsh climate and environmental hazards contribute to the structural damage of steel bridges. Substantial dynamic loading from heavy trucks can worsen existing cracks. This paper investigates the dynamic behavior of a steel box girder bridge, the Szapáry bridge, with a fractured girder subjected to moving truck loads. Initially, a finite element model simulates the seven-span continuous bridge behavior during static load testing. The model also accurately simulated the dynamic load tests performed. A series of hypothetical damage (fractured girder) and dynamic loading scenarios reveal the effects of truck positions on the damaged bridge's dynamic response. Dynamic displacement induced due to traffic loading helps evaluate a bridge's structural health. Results of the parametric analysis highlight that several factors, including truck velocity and position, bridge span length, and truck lateral spacing, significantly affect the dynamic vibration of the fractured bridge. The results offer insight into the effectiveness of dynamic response analysis for conditioned-based maintenance and damage detection.

Open Access: Yes

DOI: 10.3233/ATDE240528

Impact of Randomized Soil Properties and Rock Motion Intensities on Ground Motion

Ayele Chala R. P. Ray

Publication Name: Advances in Civil Engineering

Publication Date: 2024-01-01

Volume: 2024

Issue: Unknown

Page Range: Unknown

Description:

Seismic site response is inevitably influenced by natural variability of soil properties and anticipated earthquake intensity. This study presents the influence of variability in shear wave velocity (Vs) and amplitude of input rock motion on seismic site response analysis. Monte Carlo simulations were employed to randomize the Vs profile for different scenarios. A series of 1-D equivalent linear (EQL) seismic site response analyses were conducted by combining the randomized Vs profile with different levels of rock motion intensities. The results of the analyses are presented in terms of surface spectral acceleration, amplification factors (AFs), and peak ground acceleration (PGA). The mean and standard deviation of these parameters are thoroughly discussed for a wide range of randomized Vs profile, number of Vs randomizations, and intensities of input rock motions. The results demonstrate that both the median PGA and its standard deviations across different number of Vs profile realization exhibit a slight variation. As few as twenty Vs profile realizations are sufficient to compute reliable response parameters. Both rock motion intensity and standard deviation of Vs variability cause significant variation in computed surface parameters. However, the variability in the number of records used to conduct site response has no significant impact on ground response if the records closely match the target spectrum. Incorporating the multiple sources of variabilities can reduce uncertainty when conducting ground response simulations.

Open Access: Yes

DOI: 10.1155/2024/9578058

Modeling the Stiffening Behavior of Sand Subjected to Dynamic Loading

Majd Ahmad R. P. Ray

Publication Name: Geosciences Switzerland

Publication Date: 2024-01-01

Volume: 14

Issue: 1

Page Range: Unknown

Description:

In geotechnical engineering, dynamic soil models are used to predict soil behavior under different loading conditions. This is crucial for many dynamic geotechnical problems related to earthquakes, train loading and machine foundation design. Researchers agree that under dry or drained conditions, cohesionless soils increase in stiffness with each loading cycle. Soil models that simulate the dynamic behaviors of soils are often coupled with the Masing criteria. Such models neglect the impact of stiffening during cyclic loading, leading to an underestimation in the shear modulus (G). This study investigates the stiffening behavior by conducting laboratory tests on three types of Danube sands using the Resonant Column-Torsional Simple Shear device (RC-TOSS). The increase in the dynamic shear modulus with an increasing number of cycles is substantial, especially for samples with low density. Sometimes, the dynamic shear modulus doubles when loaded at high stress levels for more than 50 cycles. A new model is introduced to simulate the stiffening behavior of dry sand when subjected to cyclic torsional loading. Modifications are proposed for the Ramberg–Osgood and Hardin–Drnevich models and for the Masing criteria to overcome the limitations that accompany these models due to the influence of stiffening caused by repetitive loading being ignored. This model can be implemented in finite element and finite difference software to solve dynamic geotechnical problems.

Open Access: Yes

DOI: 10.3390/geosciences14010026

Unraveling Debris-Enhanced Local Scour Patterns around Non-Cylindrical Bridge Piers: Experimental Insights and Innovative Modeling

Mahmoud Saleh Al-Khafaji Muhanad Al-Jubouri R. P. Ray

Publication Name: Sustainability Switzerland

Publication Date: 2023-11-01

Volume: 15

Issue: 22

Page Range: Unknown

Description:

Bridge structures face a critical threat from localized scour-induced damage, prompting urgent attention to civil infrastructure resilience. Prior research has primarily focused on the influence of pier shapes on scour patterns. However, the exploration of the combined effects of various debris shapes, each possessing distinct properties, on predictive scour depth models around the non-cylindrical pier has hitherto remained less researched. This study explored the complex dynamics governing local scour around bridge piers, focusing on the influence of surface and near-surface debris. This research shed light on changes in scour depth by investigating factors like pier geometries, debris arrangements, and submersion depths. The experiments and analysis revealed the effects of various pier shapes—cylindrical, square, rectangular, oblong, oval, and lenticular—on scour patterns. Different geometries influenced primary scour zones and affected areas, with square piers causing the deepest scour and lenticular ones showing shallower instances. Scour depths typically peaked upstream across geometries, but ogival and lenticular shapes exhibited unique patterns. The research also introduced a formula that integrated debris attributes into predictive scour depth modeling, validated with favorable accuracy. Ultimately, this predictive model advances scour prediction, particularly in debris-laden flows, offering valuable insights for engineering and management practices in understanding real-world scour mechanisms and hydraulic dynamics.

Open Access: Yes

DOI: 10.3390/su152215910

Parametric Investigation of Interaction between Soil-Surface Structure and Twin Tunnel Excavation: A Comprehensive 2D Numerical Study

Hussein Ahmad Ammar N. Alnmr Ashraf Sheble R. P. Ray

Publication Name: Infrastructures

Publication Date: 2023-08-01

Volume: 8

Issue: 8

Page Range: Unknown

Description:

The growing demand for transportation tunnels in densely populated urban areas has led to the widespread adoption of twin tunnel configurations in contemporary infrastructure projects. This research focuses on investigating the complex interaction between soil, structures, and the excavation of twin tunnels. The study employs the tunnel boring machine (TBM) method and utilizes two-dimensional numerical modeling based on the finite element method (FEM). The numerical model is validated by comparing its results with field measurements obtained from a twin tunnel project in Italy, specifically the New Milan Metro Line 5. A comprehensive parametric study is conducted to analyze various parameters that influence soil–structure interaction during tunnel excavation. These parameters include the positioning of the tunnels in relation to each other, the spacing between them, the presence of structures above the tunnels, eccentricity between the structure axis and tunnel axis, and tunnel depth and diameter. Moreover, a comparative analysis is performed between scenarios with and without structures to elucidate the impact of structure presence on the interaction phenomenon. The research findings provide valuable insights into the intricate behavior of twin tunnels and their interaction with the surrounding soil and structures.

Open Access: Yes

DOI: 10.3390/infrastructures8080124

The effectiveness parameters analysis for piers scour calculation

Muhanad Al-Jubouri R. P. Ray

Publication Name: Pollack Periodica

Publication Date: 2023-07-11

Volume: 18

Issue: 2

Page Range: 48-53

Description:

A computational fluid dynamics numerical model addressed the problem of local scouring and deposition calculation for non-cohesive sediment and clear water conditions near single and double cylindrical piers. The numerical results of single cylindrical piers correlate very well with the physical model's results while are higher than the case of the double pier, especially when the large-eddy turbulence model, the van Rijn bed-load transport equation, and fine mesh size are considered. Additionally, the final numerical predictions are compared to experimental data after parameters effectiveness explores the range of results based on projected user inputs like the bed-load equation, mesh cell size, and turbulence model.

Open Access: Yes

DOI: 10.1556/606.2022.00680

Numerical simulation of replacement method to improve unsaturated expansive soil

Ammar N. Alnmr R. P. Ray

Publication Name: Pollack Periodica

Publication Date: 2023-07-11

Volume: 18

Issue: 2

Page Range: 41-47

Description:

In this paper, a parametric study is done with various removal and replacement materials to study the effectiveness of the removal and replacement method on the wetting depth in the expansive soil and the amount of differential heave caused by climate conditions and common irrigation scenarios for the southern region of Syria. Soil suction changes and associated soil deformations are analyzed using finite element codes, VADOSE/W and SIGMA/W. The paper concludes that the optimum thickness for replacement with high permeability soil should be at least 1 m. In addition, it concludes that replacing soil with a permeability coefficient lower than the permeability coefficient of the site soil contributes to a 56% and 79% reduction in total and differential heave, respectively.

Open Access: Yes

DOI: 10.1556/606.2023.00762

Machine Learning Techniques for Soil Characterization Using Cone Penetration Test Data

Ayele Chala R. P. Ray

Publication Name: Applied Sciences Switzerland

Publication Date: 2023-07-01

Volume: 13

Issue: 14

Page Range: Unknown

Description:

Seismic response assessment requires reliable information about subsurface conditions, including soil shear wave velocity (Formula presented.). To properly assess seismic response, engineers need accurate information about (Formula presented.), an essential parameter for evaluating the propagation of seismic waves. However, measuring (Formula presented.) is generally challenging due to the complex and time-consuming nature of field and laboratory tests. This study aims to predict (Formula presented.) using machine learning (ML) algorithms from cone penetration test (CPT) data. The study utilized four ML algorithms, namely Random Forests (RFs), Support Vector Machine (SVM), Decision Trees (DT), and eXtreme Gradient Boosting (XGBoost), to predict (Formula presented.). These ML models were trained on 70% of the datasets, while their efficiency and generalization ability were assessed on the remaining 30%. The hyperparameters for each ML model were fine-tuned through Bayesian optimization with k-fold cross-validation techniques. The performance of each ML model was evaluated using eight different metrics, including root mean squared error (RMSE), mean absolute error (MAE), mean absolute percentage error (MAPE), coefficient of determination ((Formula presented.)), performance index ((Formula presented.)), scatter index ((Formula presented.)), (Formula presented.), and (Formula presented.). The results demonstrated that the RF model consistently performed well across all metrics. It achieved high accuracy and the lowest level of errors, indicating superior accuracy and precision in predicting (Formula presented.). The SVM and XGBoost models also exhibited strong performance, with slightly higher error metrics compared with the RF model. However, the DT model performed poorly, with higher error rates and uncertainty in predicting (Formula presented.). Based on these results, we can conclude that the RF model is highly effective at accurately predicting (Formula presented.) using CPT data with minimal input features.

Open Access: Yes

DOI: 10.3390/app13148286

Damping of Dry Sand in Resonant Column-Torsional Simple Shear Device

Majd Ahmad R. P. Ray

Publication Name: Sustainability Switzerland

Publication Date: 2023-07-01

Volume: 15

Issue: 14

Page Range: Unknown

Description:

The damping ratio values of three different Danube sands were measured in the Resonant Column-Torsional Simple Shear device (RC-TOSS). The distinctive configuration of the RC-TOSS device employed in this investigation enabled the performance of both tests using a single sample. This research estimates and compares the damping ratio values measured with three distinct methods (two of which are in the RC test): The Free Vibration Decay (FVD), the Steady-State Vibration (SSV) methods, and the method of calculating the damping ratio from the hysteretic loops generated in the TOSS test. Both dense and loose samples were tested up to a peak-to-peak amplitude shear strain of 1%. The device provides measurements over a wide range of shear strain amplitudes. The results support the employment of the SSV methods at low strains (below 0.005%), while the FVD method gives a better estimate at higher strains (above 0.03%). The two methods and the TOSS results are in agreement with each other between 0.005% and 0.03%. The effect of the number of cycles on the damping ratio was investigated where a significant decrease was observed in the damping ratio with an increasing number of cycles. A parameter is introduced to describe the rate of this decrease, which should be considered during the structural design to reduce maintenance and life-cycle costs and enhance sustainability.

Open Access: Yes

DOI: 10.3390/su151411060

The Dynamic Properties of Sand under Torsion: A Literature Review

Majd Ahmad R. P. Ray

Publication Name: Geotechnics

Publication Date: 2023-06-01

Volume: 3

Issue: 2

Page Range: 480-514

Description:

Resonant column (RC) and the torsional simple shear (TOSS) tests have shown proven competency in acquiring precise and repeatable measurements regarding the shear modulus and damping ratio of soil. For most dynamic geotechnical problems, the shear modulus represents the stiffness of the soil, while the damping ratio describes energy dissipation. Many studies in the last few decades focused on developing the relevant equipment and investigating the effect of different soil properties on the dynamic behavior of soil. Researchers have introduced correlations to approximate this behavior without conducting dynamic torsional testing. Soil models (e.g., Ramberg-Osgood and Hardin-Drnevich) can simulate shear stress-strain curves after finding the curve-fitting parameters. Due to the complexity of dynamic behavior and its dependency on various factors in soils, the RO and HD equations help model the behavior more simply. This paper presents a literature review and evaluation of the studies, correlations, soil models, and parameters affecting the dynamic behavior of dry sand under torsion.

Open Access: Yes

DOI: 10.3390/geotechnics3020027

Assessing the Performance of Machine Learning Algorithms for Soil Classification Using Cone Penetration Test Data

Ayele Chala R. P. Ray

Publication Name: Applied Sciences Switzerland

Publication Date: 2023-05-01

Volume: 13

Issue: 9

Page Range: Unknown

Description:

Conventional soil classification methods are expensive and demand extensive field and laboratory work. This research evaluates the efficiency of various machine learning (ML) algorithms in classifying soils based on Robertson’s soil behavioral types. This study employs 4 ML algorithms, including artificial neural network (ANN), random forest (RF), support vector machine (SVM), and decision trees (DT), to classify soils from 232 cone penetration test (CPT) datasets. The datasets were randomly split into training and testing datasets to train and test the ML models. Metrics such as overall accuracy, sensitivity, precision, F1_score, and confusion matrices provided quantitative evaluations of each model. Our analysis showed that all the ML models accurately classified most soils. The SVM model achieved the highest accuracy of 99.84%, while the ANN model achieved an overall accuracy of 98.82%. The RF and DT models achieved overall accuracy scores of 99.23% and 95.67%, respectively. Additionally, most of the evaluation metrics indicated high scores, demonstrating that the ML models performed well. The SVM and RF models exhibited outstanding performance on both majority and minority soil classes, while the ANN model achieved lower sensitivity and F1_score for minority soil class. Based on these results, we conclude that the SVM and RF algorithms can be integrated into software programs for rapid and accurate soil classification.

Open Access: Yes

DOI: 10.3390/app13095758

Modelling of the Torsional Simple Shear Test with Randomized Tresca Model Properties in Midas GTS NX

Majd Ahmad R. P. Ray

Publication Name: Geotechnical and Geological Engineering

Publication Date: 2023-05-01

Volume: 41

Issue: 3

Page Range: 1937-1946

Description:

The dynamic properties of soil obtained from the torsional simple shear test (TOSS) are assumed to be uniform throughout the specimen. For some exceptional soils, this may hold true, but for the most majority of soils that we examine, it is obviously not the case, and this level of non-uniformity depends on the conditions in which the soil was formed. In this paper, we discuss a method of modelling inherently non-uniform soil specimens by representing them with elements that have an elasto-plastic simple Tresca material model with different properties (Elastic young modulus and yield stresses). The combination of properties that can simulate the nonlinear behaviour of the soil is found and calibrated using a model of the TOSS test built in the finite element software Midas GTS NX. Furthermore, the influence of rigid inclusions in the soil is studied and the results show an increase in stiffness with the increasing percentage of inclusion in the soil.

Open Access: Yes

DOI: 10.1007/s10706-023-02382-z

Evaluation of the Szapáry Long-Span Box Girder Bridge Using Static and Dynamic Load Tests

Rajmund Kuti M. Brinissat R. P. Ray

Publication Name: Infrastructures

Publication Date: 2023-05-01

Volume: 8

Issue: 5

Page Range: Unknown

Description:

This paper presents the results of a recent field test carried out before the opening phases of the Szapáry motorway bridge across the Tisza River in central Hungary. The evaluation test was based on static and dynamic load tests that provided information on deflection, stresses, and dynamic mode shapes along the bridge. The structure has two large continuous independent steel box girders that cover spans across the floodplain and river. Various configurations of truck loading applied up to 6400 kN of loading on the deck. During the static tests, string potentiometers recorded deflections at mid-span. Additionally, strain gauges enabled strain/stress measurements at the mid-point of the longest span and directly above one support. Dynamic loadings showed variation in deflection response due to vehicle speed, and ambient vibration testing led to determining vibration modes and frequencies. A three-dimensional finite-element model produced similar deflections, stresses, and modal behavior. Measured and modeled deflections and stresses indicated that the bridge performed within design margins. The testing and analysis results will be part of a future program assessing conditioned-based maintenance.

Open Access: Yes

DOI: 10.3390/infrastructures8050091

Evaluation of the Unsaturated Shear Strength Parameters of Compacted, Heaving Soil Using Geotechnical Properties

Elizabeth Theron Armand Augustin Fondjo R. P. Ray

Publication Name: E3s Web of Conferences

Publication Date: 2023-04-24

Volume: 382

Issue: Unknown

Page Range: Unknown

Description:

The shear strength is a fundamental property of soil material under structural loads. The determination of shear strength properties of unsaturated soils is challenging and time-consuming. Geotechnical predictive models can be utilized to assess the unsaturated shear strength of heaving soil. This study attempts to propose predictive models to evaluate the unsaturated shear strength parameters of compacted heaving soil. These parameters include the angle of internal friction associated with the net normal stress (φ), angle indicating the rate of increase in shear strength with respect to a change in matric suction (φb), and effective cohesion (c'). The geotechnical properties of soils were assessed through laboratory tests such as particle size distribution, consistency limits, specific gravity, modified Proctor compaction test, swelling test, suction test, and advanced triaxial testing. Multivariate analysis was conducted using NCSS 12 software to design the models. The validation of models includes the determination coefficient, probability value, comparing experimental values with predicted values, and comparing the developed models with other model found in recent literature. The models engineered in this study can estimate the unsaturated shear strength parameters of compacted heaving soil with acceptable precision.

Open Access: Yes

DOI: 10.1051/e3sconf/202338202002

A comparative study of local scour depth around bridge piers

Muhanad Al-Jubouri R. P. Ray

Publication Name: Pollack Periodica

Publication Date: 2023-03-07

Volume: 18

Issue: 1

Page Range: 100-105

Description:

Scour is the leading cause of bridge collapse beneath any bridge pier located within the waterway. A numerical-based hydraulic model named the Hydrologic Engineering Centre River Analysis System and a mathematical model of the Florida Department of Transport were implemented to investigate their performance and accuracy in estimating the maximum scour depth beneath bridge piers where large and small-scale physical prototypes are used as a benchmark. The main findings are that a hydraulic model is an effective tool when employing the Colorado State University equation, which compares well with physical prototypes irrespective of the variation in piers' size and shape. Also, it has achieved more consistent results than the Froehlich and the Florida Department of Transport methodologies.

Open Access: Yes

DOI: 10.1556/606.2022.00649

A State-of-the-Art Review and Numerical Study of Reinforced Expansive Soil with Granular Anchor Piles and Helical Piles

Rashad Alsirawan Ammar N. Alnmr R. P. Ray

Publication Name: Sustainability Switzerland

Publication Date: 2023-02-01

Volume: 15

Issue: 3

Page Range: Unknown

Description:

Expansive soils exist in many countries worldwide, and their characteristics make them exceedingly difficult to engineer. Due to its significant swelling and shrinkage characteristics, expansive soil defies many of the stabilization solutions available to engineers. Differential heave or settlement occurs when expansive soil swells or shrinks, causing severe damage to foundations, buildings, roadways, and retaining structures. In such soils, it is necessary to construct a foundation that avoids the adverse effects of settlement. As a result, building the structure’s foundations on expansive soil necessitates special consideration. Helical piles provide resistance to uplift in light structures. However, they may not fully stabilize foundations in expansive soils. A granular anchor pile is another anchor technique that may provide the necessary resistance to uplift in expansive soils using simpler methods. This review and numerical study investigate the fundamental foundation treatments for expansive soils and the behavior of granular anchors and helical piles. Results indicate that granular anchor piles performed better than helical piles for uplift and settlement performance. For heave performance, the granular anchor and helical piles perform nearly identically. Both achieve heave reductions greater than 90% when L/H > 1.5 and D = 0.6 m.

Open Access: Yes

DOI: 10.3390/su15032802

Generation and Evaluation of CPT Data Using Kriging Interpolation Technique

Ayele Chala R. P. Ray

Publication Name: Periodica Polytechnica Civil Engineering

Publication Date: 2023-01-01

Volume: 67

Issue: 2

Page Range: 545-551

Description:

The cone penetration test (CPT) has been the de facto field exploration method in geotechnical engineering for decades. Variations of CPT can measure parameters for seismic, environmental, and hydrological applications. Analyzing response often requires properties in areas that have little or no data. Therefore, given the limited CPT data, it is critical to understand how to accurately estimate the soil properties at unsampled locations. In this paper, we generated soil shear wave velocity profiles using the kriging interpolation technique and assessed their performance using site response analysis. Four kriging interpolation-based shear wave velocity profiles and four additional CPT-based shear wave velocity profiles defined site conditions for response analysis. We performed a series of 1-D equivalent linear site response analyses using STRATA software. The site response analysis results are presented as amplification factors (AF), peak ground acceleration (PGA) profiles, surface spectral acceleration, and surface acceleration time histories. Compared to CPT-based profiles, the results of kriging interpolation-based profiles were evaluated and discussed. The results confirmed the reliability of the kriging interpolation technique in predicting soil parameters at unsampled locations.

Open Access: Yes

DOI: 10.3311/PPci.21865

The Significance of Data Integration in Geotechnical Engineering: Mitigating Risks and Enhancing Damage Assessment of Expansive Soils

Ammar N. Alnmr R. P. Ray

Publication Name: Chemical Engineering Transactions

Publication Date: 2023-01-01

Volume: 107

Issue: Unknown

Page Range: 541-546

Description:

Geotechnical Engineering is a data-driven specialty that models the behavior of soil and rock as engineering materials. Due to their nature, however, much effort is directed toward defining the material properties and extent of various soil and rock on a site (buildings, bridges, dams) or region (transportation infrastructure). The great extent and variability of soil as an engineering material have led to the development of material, field exploration, and laboratory testing databases. Some have become national in scope, while others have expanded along specialist lines (e.g., earthquakes, landslides). This paper presents a typical application that investigates the impact of swelling clays and discusses its integration into the BENIP framework, with an emphasis on its role in advancing sustainability in geotechnical engineering. The study employs artificial neural networks as a modeling tool to predict crucial parameters such as dry density and in-situ confining stress, which directly influence volumetric changes in the soil. By minimizing these changes, potential damage associated with swelling clays, including ground movement, foundation deterioration, and infrastructure instability, can be mitigated. The results of the study exhibit promising outcomes, signifying the potential effectiveness of the proposed neural network models in promoting sustainability in geotechnical engineering.

Open Access: Yes

DOI: 10.3303/CET23107091

The Methodologies and Main Challenges of Assessment the Multi-Hazard Interaction and Risk Management Associated with Roads Infrastructures and Dam Safety: A Review

Hayder Thabit Al Hudaib R. P. Ray

Publication Name: International Journal of Integrated Engineering

Publication Date: 2023-01-01

Volume: 15

Issue: 7

Page Range: 174-188

Description:

The idea of multi-hazard interactions and risk assessment, particularly in relation to both natural hazards and hazards triggered by anthropogenic processes, has been widely used, especially in recent decades. Numerous areas worldwide, as well as various sectors, face exposure to multiple hazards. These hazards encompass natural phenomena like floods, earthquakes, hurricanes, and more. In comparison, the human-induced or anthropogenic processes associated with infrastructure development, along with other potential human activities such as, land and cover use change, contribute to the overall hazard landscape. Both natural hazards and anthropogenic-induced directly led to infrastructure collapse and loss of functionality with other consequences for human lives, economy, beside the environment impacts. Limited studies have been conducted on the implementation of the comprehensive multi-hazard interaction approach, which is globally or regionally required, along with detailed studies on the interaction between different multi-hazard sources and their interrelationships in short-term or long-term scenarios. The current research aims to review previous literature and studies on the multi-hazard interaction approach, methodologies of visualization and classification, as well as explores the potential of multi-hazard associated with road networks, infrastructures, and dams. The research utilizes simulation various models and tools such as, Geographic Information System (GIS) beside Remote Sensing (Rs) techniques. The current study concludes that using multi-hazard maps, hazard matrix, and fragility curves represents highly valuable and very useful and flexible tools for implementing and visualization hot spot areas exposure by multi-hazard consequences and vulnerability analysis for short and long-term scenarios. In addition, the current review highlighted for development a holistic conceptual framework for multi-hazard and risk assessment associated with hydraulic structures such as dams, road networks and infrastructures with hazard exposure analysis to be used as tools for a decision support system (DSS) in order to develop urban resilience, risk management and hazard mitigations.

Open Access: Yes

DOI: 10.30880/IJIE.2023.15.07.017

Sustainable levee construction along the Danube River

Edina Koch M. Marchi R. P. Ray L. Tonni

Publication Name: Proceedings of the International Congress on Environmental Geotechnics

Publication Date: 2023-01-01

Volume: Unknown

Issue: Unknown

Page Range: 399-408

Description:

Nowadays' changing weather conditions and the resulting increasing flood levels make flood protection improvement essential. In Hungary, in the Szigetköz floodplain area, a complex water resources management unit of the Upper part of the Danube River, the rehabilitation of the water levels, and the setting back of the settled low and middle water levels had become necessary. It has been achieved by relocating the estuary of the Mosoni-Danube River and constructing a complex water control structure. A new ~1.5 km long levee connects to the structure. Due to a large volume of fine-grained blanket material on the site, the possibility arose to build a section of the levee using the blanket material without applying a cut-off wall to prevent water flow through the levee. The geotechnical parameters of the available local material were based on a complex site investigation program. According to the results of the field and laboratory tests, the blanket layer was suitable as fill material and could be compacted to the required 90% degree of compaction using standard machinery and procedures. Plaxis 2D software using fully coupled flow-deformation analysis, imitating the previously registered flood waves, modeled seepage and stability behaviour to evaluate the ultimate limit states of the levee constructed from the blanket material. The analysis proved the adequacy of the blanket material, avoiding the necessity for a barrier within the embankment. The use of local blanket material as fill eliminated the need to excavate and transport additional material, reducing environmental impact, shortening construction time, and saving costs on the project.

Open Access: Yes

DOI: 10.53243/ICEG2023-396

Pile optimization in slope stabilization by 2D and 3D numerical analyses

M. Movahedi Rad M. Amine Benmebarek R. P. Ray Sadok Benmebarek

Publication Name: International Journal of Geotechnical Engineering

Publication Date: 2022-01-01

Volume: 16

Issue: 2

Page Range: 211-224

Description:

In this paper, numerical computations using PLAXIS 2D and 3D have been conducted to optimize a row of piles in cohesive-frictional slope stabilization. First, 2D parametric studies were performed to identify both the optimal location and length of the pile as well as the effect of pile head conditions. Next, more rigorous parametric studies taking account of the exact geometry was carried out using 3D analyses. According to the obtained results, the fixed pile head located at the slope middle better improves the stability and reduces the optimal length of the pile. Piles with free head contribute marginally to the increased factor of safety of cohesive-frictional slope. In 3D analyses, it is shown that spacing ratio beyond S/D = 4 (S: pile spacing, D: diameter of the pile), the soil will flow between piles leading to a total vanish of the arching effect when S/D exceeds 12. Comparing the results, the limitation of 2D analysis for piled cohesive-frictional slope is highlighted.

Open Access: Yes

DOI: 10.1080/19386362.2021.1972628

Comparison between Ramberg-Osgood and Hardin-Drnevich soil models in Midas GTS NX

Majd Ahmad R. P. Ray

Publication Name: Pollack Periodica

Publication Date: 2021-12-31

Volume: 16

Issue: 3

Page Range: 52-57

Description:

This paper studies the two widely used material models for predicting the dynamic behavior of soils, the Ramberg-Osgood and Hadrin-Drnevich models. Resonant column and torsional simple shear test results on dry sand were used to calibrate and evaluate the model built in the finite element software Midas GTS NX. Both material models are already implemented by the software. This study estimates the ability and efficiency of both soil models coupled with the Masing criteria to predict the behavior of soil when subjected to irregular loading patterns, (e.g., earthquakes), and measure the two most important dynamic properties, the dynamic shear modulus, and the damping ratio.

Open Access: Yes

DOI: 10.1556/606.2021.00353

Review of the effect of sand on the behavior of expansive clayey soils

Ammar N. Alnmr R. P. Ray

Publication Name: Acta Technica Jaurinensis

Publication Date: 2021-11-24

Volume: 14

Issue: 4

Page Range: 521-552

Description:

Clayey soils often showed undesirable engineering behavior such as low bearing capacity, swelling and shrinkage characteristics. However, chemical improvement, thermal improvement and improvement by additives like lime, cement and sand offer an efficient technique to overcome the problems resulting from Expansive soils. This paper presents a review of the swelling behavior of sand-clay mixtures as well as the effect of sand on the physical and mechanical characteristics of expansive soils. Results highlight the importance of sand in improving the behavior of expansive soils. Finally, the most important general conclusions about the behavior of expansive soils and suggestions for future researches are highlighted.

Open Access: Yes

DOI: 10.14513/actatechjaur.00611

Methods to detect and measure scour around bridge foundations

Muhanad Al-Jubouri R. P. Ray

Publication Name: Acta Technica Jaurinensis

Publication Date: 2021-11-24

Volume: 14

Issue: 4

Page Range: 631-649

Description:

Bridges are indispensable structures vital to the operation of road and rail transportation networks. Crossing rivers and artificial waterways, however, presents a risk to their foundations due to scour actions. Scour is the number one cause for bridge failures and may occur beneath any bridge, large or small, with supports located within the waterway. This paper provides a summary of present scour detection and measurement equipment and associated assessment methodologies. In this regard, particular emphasis is placed on structural health monitoring better to evaluate the presence and influence of potential scour. A Sensitivity Analysis on a newly introduced monitoring system is also assumed. Furthermore, much research has been undertaken to create a technology that can instantly identify and detect bridge scour, improving survey reliability through prior inspection and prompt intervention. This research will explore and evaluate bridge scour detection methods employed and suggest a possible path for developing the detection system to identify scour depth effectively and efficiently. Finally, our key aim is to minimize human effort in identifying and bridge scour by using a quick, easy-to-use, cost-effective process, resulting in fewer injuries and economic savings.

Open Access: Yes

DOI: 10.14513/actatechjaur.00626

Estimation of optimum moisture content and maximum dry unit weight of fine-grained soils using numerical methods

Elizabeth Theron Armand Augustin Fondjo R. P. Ray

Publication Name: Walailak Journal of Science and Technology

Publication Date: 2021-08-15

Volume: 18

Issue: 16

Page Range: Unknown

Description:

Soil compaction is one of the basic engineering techniques, which is carried out to guarantee the stability of soils dependent on specified strength. Nonetheless, in large-scale construction projects, the estimation of compaction features required tremendous effort and time that can be saved utilizing empirical relationships at the initial phases. It becomes critical to develop models to predict the compaction features, namely the maximum dry unit weight (γdmax) and optimum water content (WOP). This article attempts to develop models to predict the γdmax and WOP of fine-grained clay soils. Geotechnical tests such as grain size distribution, Atterberg limits, specific gravity, and proctor compaction tests are performed to assess soil samples' physical and hyro-mechanical characteristics. Multivariate analysis is conducted using MINITAB 18 software to develop the predictive models. The validation process of developed models includes the determination coefficient, probability value (p-value), comparison of the predicted values with experimental values, comparison of the models proposed in this study with other existing models found in the recent literature, and employing a different soil data set. The predicted values obtained from the models proposed in this research project are more accurate than other models developed recently. The proposed models estimate the compaction features of fine-grained clay soils with acceptable precision.

Open Access: Yes

DOI: 10.48048/wjst.2021.22792

Stabilization of Expansive Soils Using Mechanical and Chemical Methods: A Comprehensive Review

Elizabeth Theron Armand Augustin Fondjo R. P. Ray

Publication Name: Civil Engineering and Architecture

Publication Date: 2021-08-01

Volume: 9

Issue: 5

Page Range: 1289-1294

Description:

The presence of expansive soils on construction sites is problematic in geotechnical engineering. The swell-shrink behaviour makes these soils not suitable to be used in their natural state. The expansive soil damages cause financial loss yearly more than floods, hurricanes, tornadoes, and earthquakes combined. Moreover, the cost of cut to spoil of expansive soils during construction projects has continued to rise because of the high cost of earthworks, haulage, and the increasing scarcity of spoil areas because of the built environment. Nonetheless, a proper stabilization technique can significantly enhance the expansive soil's properties. The research project attempts to review, report the limits and merits of mechanical and chemical methods utilized to stabilize expansive soils in line with their efficiency, environmental concerns, and cost-effectiveness. A review of mechanical and chemical treatment techniques is conducted in this regard. Ultimately, each stabilization method exhibits its merits and limitations. The lack of standards for the treatment of swelling soils is a significant problem in engineering practice. Specialists in the domain of soil treatment must work together to obtain an optimized stabilization approach and protocol. Moreover, engineers should perform a geoenvironmental assessment appropriate for chemical stabilization methods and additives utilized. This research work contributes as a guideline in the selection and application of chemical and mechanical stabilization methods.

Open Access: Yes

DOI: 10.13189/cea.2021.090503

Models for predicting the suction of heaving compacted soils using geotechnical properties

Elizabeth Theron Armand Augustin Fondjo R. P. Ray

Publication Name: Iop Conference Series Earth and Environmental Science

Publication Date: 2021-04-20

Volume: 727

Issue: 1

Page Range: Unknown

Description:

Soil suction is the major property that controls the behaviour of unsaturated soils. Suction estimation is challenging both in the lab and the field. Various instruments to measure the suction have been developed with the recent technological advancements. Nonetheless, there are still limitations in regards to the reliability, cost, suction range, accessibility, scope of activity, and appropriateness for use either within the field or lab settings. The filter paper method is probably the simplest procedure to measure the suction for the entire range both in the field and the lab. Nevertheless, the procedure takes time. To alleviate the requirement for conducting this test, it becomes imperative to develop mathematical predictive models for soil suction. In this study, a detailed survey was carried out across the Free State province, South Africa, and sampling points identified. Samples were tested for their geotechnical properties. The influence of the geotechnical properties on soil suction was studied. Multivariate regression analysis was carried out utilizing MINITAB 18 program to develop the mathematical predictive models.

Open Access: Yes

DOI: 10.1088/1755-1315/727/1/012016

Investigation of the influencing soil parameters on the air entry values in soil-water characteristic curve of compacted heaving soils

Elizabeth Theron Armand Augustin Fondjo R. P. Ray

Publication Name: Civil Engineering and Architecture

Publication Date: 2021-01-01

Volume: 9

Issue: 1

Page Range: 91-114

Description:

The air-entry value (AEV) is a fundamental parameter of the soil-water characteristic curve (SWCC). AEV is the minimum matric suction value required for entry of air into soil voids. The primary objective of this research work is to assess the impact of geotechnical index properties, swelling properties, mineral composition on AEV of compacted heaving soils, and discuss how they affect AEV. Soil properties were investigated through lab tests such as grain size distribution (GSD), specific gravity, Atterberg limits, linear shrinkage, free swell index, free swell ratio, X-ray diffraction, compaction test, and soil suction measurement. SWRC Fit program was used to perform non-linear fitting of the SWCC based on models VG, DB, FX, LN, and BL. Surface plot of data was used to characterize the impact of soil properties on AEV. It was observed that AEV is ranging from 10 kPa to 20.20 kPa, models DB and BL gives the best fitting SWCC. The percent of smectite mineral exhibits a significant impact on AEV. Swelling properties such as free swell index and free swell ratio influence the AEV with a respective determination coefficient of 85.72%, 88.68%. The plasticity index, linear shrinkage, specific gravity, and dry unit weight impact the AEV with a respective determination coefficient of 95%, 95.45%, 90.43%, 94.29%. The fine-grained content, clay fraction, void ratio, and water content influence the AEV with a respective determination coefficient of 97.95%, 84.89%, 80%, 94.31%. The finer the soil, the higher the AEV. The activity of clay and percent of illite mineral exhibit a marginal effect on the AEV.

Open Access: Yes

DOI: 10.13189/cea.2021.090108

Semi-empirical model for predicting the swelling stress of compacted, unsaturated expansive soils

Elizabeth Theron Armand Augustin Fondjo R. P. Ray

Publication Name: Civil Engineering and Architecture

Publication Date: 2021-01-01

Volume: 9

Issue: 1

Page Range: 225-239

Description:

Heaving soils are the most problematic worldwide. These soils develop swelling stress that produces uplift forces detrimental to the foundations. In engineering practice, swelling stress is not considered in general. Considering the swelling stress in foundation design enhances the service life of construction. The oedometer swelling test is the technique ordinarily used to assess the swelling stress. Nonetheless, the oedometer swelling test is cumbersome, time-consuming, making the test unattractive, and not cost-effective for the low-cost housing project. The objective of this research work is to propose a model to predict swelling stress as an alternative to oedometer testing. Geotechnical studies such as Atterberg limits, particle size distribution, free swell ratio, specific gravity, linear shrinkage, suction measurement, Proctor compaction test, and zero-swell test are performed to estimate the soil properties. Multivariate regression analysis is performed using NCSS.11 Program to develop the predictive model. The model is assessed base on the following: determining coefficient value, comparing predicted values with experimental values, comparing the proposed model with other existing models found in the literature. Besides, the Box-cox transformation function is used to improve the accuracy of the model. The developed model can be utilized to assess the swelling stress of compacted heaving soils, and it is much more accurate than other existing models.

Open Access: Yes

DOI: 10.13189/cea.2021.090119

Verification of the Ramberg-Osgood material model in midas GTS NX with the modeling of torsional simple shear tests

Zs Szilvágyi R. P. Ray

Publication Name: Periodica Polytechnica Civil Engineering

Publication Date: 2018-05-22

Volume: 62

Issue: 3

Page Range: Unknown

Description:

This study focuses on the back analysis of a geotechnical laboratory test with nonlinear finite element modeling using the Ramberg-Osgood material model. This model has been used by several authors recently for nonlinear ground response analysis and it has been implemented by Midas into their commercial finite element code Midas GTS NX 2014. The verification of the model for 1D nonlinear site response analysis can be found in the documentation of the software package. In this study, Torsional Simple Shear tests were modeled and a comprehensive study was performed to provide verification of the material model for static torsional loading and axisymmetric conditions.

Open Access: Yes

DOI: 10.3311/PPci.11191

Vulnerability assessment of residential buildings in Jeddah: A methodological proposal

O. Kegyes-Brassai Ahmed Al-ghamadi Md Faiz Shah Anas Ahmed R. P. Ray

Publication Name: International Journal of Geomate

Publication Date: 2018-01-01

Volume: 14

Issue: 44

Page Range: 134-141

Description:

The City of Jeddah in Saudi Arabia is expanding rapidly, in terms of new buildings and increasing population. The rapid urbanization leads to higher risk from seismic events; even in areas of moderate seismicity such as this city. The present study addresses the rapid evaluation of a large number of buildings in Jeddah involving steps to determine hazard, assessing building stock, and computing vulnerability with a scoring method from FEMA 155. Two districts were selected for investigation based on a cluster analysis applied to population and building data from the local municipality. One selected district was a contemporary developed urbanized area, and the other was a more traditional area. Such selection offered the possibility to compare vulnerability of buildings built according to different seismic codes and to make assumptions about the rest of the city based on typical structures of districts. The basic structural score was determined considering the building structure and moderate seismicity of the region using score modifiers, e.g. vertical irregularity score modifier; soil score modifier assuming sabkahs. The results of the investigation reveal a different level of vulnerability and areas where intervention is needed. The method can be applied for further analysis of the city.

Open Access: Yes

DOI: 10.21660/2018.44.85087

Extraction/Infusion Rate Effects on Continuous Soil-Water Characteristic Curves for Clayey Sand

Inthuorn Sasanakul Muwafaq Awad R. P. Ray

Publication Name: Geotechnical Special Publication

Publication Date: 2018-01-01

Volume: 2017-November

Issue: GSP 301

Page Range: 28-37

Description:

An automated tempe cell test system was used in this study to measure soil-water characteristic curves (SWCC) for both wetting and drying paths. The test was performed by extracting water at a controlled rate from the soil specimen during drying and infusing water into the specimen during wetting. In this paper, effect of extraction and infusion rate on the shape, parameters, and hysteresis of the SWCCs were examined for pure sand and clayey sand. Results show that the rate has no effect on the SWCCs for pure sand, but has a measurable effect for clayey sand. Effects of the rate are observed on all the SWCC parameters, particularly slope of the SWCCs and re-saturation parameters. Consequently, the wetting path is more influenced by the rate than the drying path. The automated system can be used efficiently for sand at fast rates but for clayey sand, the rate effect should be considered.

Open Access: Yes

DOI: 10.1061/9780784481684.004

Effects of local ground conditions on site response analysis results in Hungary

O. Kegyes-Brassai Zs Szilvágyi None Wolf R. P. Ray

Publication Name: Icsmge 2017 19th International Conference on Soil Mechanics and Geotechnical Engineering

Publication Date: 2017-01-01

Volume: 2017-September

Issue: Unknown

Page Range: 2003-2006

Description:

Ground conditions play an important role for both seismic hazard assessment and structural design for seismic actions. Generally, 1D site response analysis is the first step toward evaluating local conditions. Often the process is simplified by applying a single reference peak ground acceleration general response spectrum based on soil category. Seismic waves are amplified selectively by near-surface soil deposits that possess strain dependent stiffness and damping parameters that vary with each layer as well as with depth. In order to take these local ground conditions into account, field investigations were carried out for this study. Seismic CPT and MASW measurements were used for determining in situ small strain stiffness profiles at different locations in Hungary. Results of the investigations were used as input data for ground response analyses. Results are presented to show benefits of the detailed investigations as compared to simplified analysis methods based on estimated soil parameters and to EC-8 design spectra.

Open Access: Yes

DOI: DOI not available

Predictive equations for soil shear-wave velocities of Hungarian soils based on MASW and CPT measurements around Győr

P. Tildy O. Kegyes-Brassai R. P. Ray

Publication Name: Acta Geodaetica Et Geophysica

Publication Date: 2016-12-01

Volume: 51

Issue: 4

Page Range: 685-707

Description:

Determination of shear-wave (S-wave) velocity profiles is the first step in seismic hazard assessment of a town, because the dynamic parameters of local soil types are vital for seismic response analysis of a specific area in order to determine the local soil effect in a case of a seismic event for seismic risk analysis. S-wave velocity profiles have been determined for many areas within Győr. Extensive use of historical boring logs allowed for correlations and reasonable extrapolation of soil performance throughout the area. This has led to a pattern of soil layer distributions and delineates several different soil zones for Győr.

Open Access: Yes

DOI: 10.1007/s40328-015-0148-y

Soil shear modulus from resonant column, torsional shear and bender element tests

P. Hudacsek Zs Szilvágyi R. P. Ray

Publication Name: International Journal of Geomate

Publication Date: 2016-01-01

Volume: 10

Issue: 2

Page Range: 1822-1827

Description:

This study compares results from three different testing methods: Resonant Column, Torsional Simple Shear, and Bender Element tests to determine shear modulus. The resonant column and torsional shear tests were performed on the same hollow cylinder specimen. The bender element test was performed on a triaxial specimen with the same void ratio and confining stress as well as others. Several effects were studied, among them confining stress, shear strain amplitude and for the bender element, anisotropic confinement. Testing methods and data analysis are discussed in the paper because data interpretation is very important in these tests. Results showed that the shear modulus values were almost identical between the resonant column and torsional shear but varied somewhat with the bender element results. Further research will focus on influence of stress anisotropy preparation methods.

Open Access: Yes

DOI: 10.21660/2016.20.39871

Levels of what and how in the education of geo-engineering on problematic soils

R. Szepeshazi Peter Scharle R. P. Ray

Publication Name: Geotechnical Engineering

Publication Date: 2015-12-01

Volume: 46

Issue: 4

Page Range: 110-113

Description:

Majority of recent studies discussing the development issues of civil engineering education focus the attention on the innovative teaching and learning methods. Evolution of the engineers' habit of mind demands, in addition, the conscious harmonization and synchronization of educational level, basic mathematical and mechanical preliminaries and professional content. Consideration of the interdependence among these factors results in some conclusions usable for educators interested in creating innovative curricula. Distinction between BEng and MEng levels of competence has to be identified properly. Geotechnical works on or in problematic soils deserve this attention, in particular.

Open Access: Yes

DOI: DOI not available

Seismic performance evaluation of an irregular RC frame building

Zs Szilvágyi R. P. Ray

Publication Name: Geotechnical Engineering for Infrastructure and Development Proceedings of the Xvi European Conference on Soil Mechanics and Geotechnical Engineering Ecsmge 2015

Publication Date: 2015-01-01

Volume: 7

Issue: Unknown

Page Range: 4185-4190

Description:

This paper focuses on overcoming difficulties associated with the assessment of a multi-story reinforced concrete frame building constructed in several phases over time, with an irregular layout. Trying to develop a coherent, safe and sensible design in such a case is indeed a challenge for structural and geotechnical engineers. The retrofitting problem is made worse by incomplete data, a building with shallow and deep foundations, and architectural "re-purposing" of the entire structural assembly. A state-of-the art seismic performance evaluation according to Eurocode 8-3 is presented as a case study, with special emphasis on the topics of numerical modeling and foundation modeling. Potential modeling simplifications are considered as well.

Open Access: Yes

DOI: DOI not available

Analysis and design of piles for dynamic loading

None Wolf R. P. Ray

Publication Name: 18th International Conference on Soil Mechanics and Geotechnical Engineering Challenges and Innovations in Geotechnics Icsmge 2013

Publication Date: 2013-01-01

Volume: 4

Issue: Unknown

Page Range: 2839-2842

Description:

With the acceptance of Eurocode 8 in Hungary a new level of seismic design is now necessary. This paper outlines some of the past history and present implementation of foundation design for seismic loading as practiced in Hungary. It shortly describes the possibilities of modeling foundations (fix support, linear elastic support, non-linear elastic support) during the design of the superstructure, and introduces the Hungarian practice. The influence of the different support's methods for the bearing forces/stresses of a superstructure is analyzed on a typical reinforced concrete office building using SAP2000 finite element software. The results of the calculation are compared through the moment of a column, the deflection and the support reaction.

Open Access: Yes

DOI: DOI not available

Applying earthquake risk analysis methods to a town in Hungary

O. Kegyes-Brassai R. P. Ray

Publication Name: 18th International Conference on Soil Mechanics and Geotechnical Engineering Challenges and Innovations in Geotechnics Icsmge 2013

Publication Date: 2013-01-01

Volume: 2

Issue: Unknown

Page Range: 1519-1522

Description:

Determining the earthquake risk of buildings in a town or settlement has lately become a more prominent issue. The process can provide important data for governments, authorities, disaster management and insurance companies to better understand risks to many buildings and engineering systems rather than a single building. This paper addresses the rapid evaluation of a large number of similar buildings in one area using a forecasting approach. Back-casting mainly considers the effect of previous earthquakes by listing and categorizing the damaged buildings and casualties. Forecasting offers a method to evaluate the possible damages in advance, however many uncertainties need to be taken into consideration. A fast and simple method should be developed to avoid the time and expertise required from research-based approaches. The steps involve determination of the hazard, assessing building stock, and computing vulnerability. The method for determination of vulnerability functions is a non-linear static analysis using a bilinear approximation of the capacity curve, assuming first mode force distribution and mode shape thus linear strength distribution. From the curve of the seismic demand and the shear capacity of the building, the vulnerability function of the building can be obtained. These vulnerability functions should be derived for typical layouts; offering a family of curves allowing the experts to decide the vulnerability category of a specific building on-site based on visual screening. With the given value of possible PGA (peak ground acceleration), expected damages can then be estimated.

Open Access: Yes

DOI: DOI not available

Measuring and modeling the dynamic behavior of Danube Sands

Zs Szilvágyi R. P. Ray

Publication Name: 18th International Conference on Soil Mechanics and Geotechnical Engineering Challenges and Innovations in Geotechnics Icsmge 2013

Publication Date: 2013-01-01

Volume: 2

Issue: Unknown

Page Range: 1575-1578

Description:

The adaptation of Eurocode 8 and development of high speed rail system in Hungary has created a greater need to define dynamic behavior of local soil groups. Danube sands compose an important segment of these soils and present the geotechnical engineer with several design challenges. The soils are present at river crossings and major development parcels throughout Hungary. Although the engineering behavior of these sands can vary over a wide range, they retain some common characteristics that will help the engineer to make decisions about geotechnical and structural designs. Samples of Danube sands were brought in the laboratory for dynamic testing, which included resonant column and torsional simple shear testing. This paper summarizes the dynamic behavior of this typical local soil group with emphasis on the dynamic properties themselves. Researches will find the methods and approach to evaluating properties helpful in their work while design engineers will understand how these properties are applied.

Open Access: Yes

DOI: DOI not available

Integrating nonlinear pile behavior with standard structural engineering software

J. Szép R. P. Ray

Publication Name: 18th International Conference on Soil Mechanics and Geotechnical Engineering Challenges and Innovations in Geotechnics Icsmge 2013

Publication Date: 2013-01-01

Volume: 4

Issue: Unknown

Page Range: 2869-2872

Description:

It is common in the practice of bridge design to analyze the superstructure, substructure, and foundation components separately. Applying this kind of modeling, soil-structure interaction effects can only be approximated with moderate accuracy. The foundation stiffness can greatly influence the internal forces, stresses, and displacements of superstructure. This is especially true for portal frame and integral bridges. Better modeling of soil-structure interaction can use three-dimensional geotechnical FEM programs, where the true soil-stucture environment can be analyzed. It is possible to use nonlinear constitutive models; capable of modeling soil behavior accurately, however it is difficult, time consuming, and costly in day-to-day practice.

Open Access: Yes

DOI: DOI not available