Giuseppe Carlo Marano

57382102800

Publications - 8

Sustainable and cost-effective optimal design of steel structures by minimizing cutting trim losses

Publication Name: Automation in Construction

Publication Date: 2024-11-01

Volume: 167

Issue: Unknown

Page Range: Unknown

Description:

Since the beginning of the structural optimization field, the optimal design was characterized by the least-weight configuration. In this sense, all the researchers agreed on adopting the minimum-weight optimization statement as the most promising approach to achieve an optimized employment of material. However, especially for steel structures, this approach completely fails the primary goal of encouraging standardization of pieces during the production phase. Except for rare cases, increasing diversity among structural elements leads to a dramatic increase in the financial cost as well as the environmental impact of the structure because of the material waste generated during the cutting procedure. In this paper, a real-coded Genetic Algorithm has been adopted and the well-known one-dimensional Bin Packing Problem has been implemented within the structural optimization process. The Objective Function formulation lies in a marked change of the paradigm in which the target function is represented by the amount of steel required by the factory instead of the structural cost (e.g. weight). The proposed approach is tested on different steel structures moving from 2D truss beams to 3D domes. Addressing the optimal stock of existing elements leads to a significant waste reduction of 40% in almost all the investigated case studies.

Open Access: Yes

DOI: 10.1016/j.autcon.2024.105724

Numerical Covariance Evaluation for Linear Structures Subject to Non-Stationary Random Inputs

Publication Name: Computation

Publication Date: 2024-03-01

Volume: 12

Issue: 3

Page Range: Unknown

Description:

Random vibration analysis is a mathematical tool that offers great advantages in predicting the mechanical response of structural systems subjected to external dynamic loads whose nature is intrinsically stochastic, as in cases of sea waves, wind pressure, and vibrations due to road asperity. Using random vibration analysis is possible, when the input is properly modeled as a stochastic process, to derive pieces of information about the structural response with a high quality (if compared with other tools), especially in terms of reliability prevision. Moreover, the random vibration approach is quite complex in cases of non-linearity cases, as well as for non-stationary inputs, as in cases of seismic events. For non-stationary inputs, the assessment of second-order spectral moments requires resolving the Lyapunov matrix differential equation. In this research, a numerical procedure is proposed, providing an expression of response in the state-space that, to our best knowledge, has not yet been presented in the literature, by using a formal justification in accordance with earthquake input modeled as a modulated white noise with evolutive parameters. The computational efforts are reduced by considering the symmetry feature of the covariance matrix. The adopted approach is applied to analyze a multi-story building, aiming to determine the reliability related to the maximum inter-story displacement surpassing a specified acceptable threshold. The building is presumed to experience seismic input characterized by a non-stationary process in both amplitude and frequency, utilizing a general Kanai–Tajimi earthquake input stationary model. The adopted case study is modeled in the form of a multi-degree-of-freedom plane shear frame system.

Open Access: Yes

DOI: 10.3390/computation12030050

A Sustainable Approach for Reversing the Structural Design Process of Steel Structures: From the Traditional Minimum-Weight Approach to the Cutting Losses Minimization

Publication Name: Advances in Transdisciplinary Engineering

Publication Date: 2024-01-01

Volume: 59

Issue: Unknown

Page Range: 446-454

Description:

In this research, a Genetic Algorithm (GA) has been developed and the well-known one-dimensional bin packing problem (BPP) has been implemented within the structural optimization process. The Objective Function formulation lies in a marked change of the paradigm in which the target function is represented by the amount of steel required by the factory instead of the structural cost (e.g. weight). The best design is obtained by varying the geometry properties of the members and the cross-section assignation ensuring optimal stock of existing elements. Finally, the structural cost and the Carbon emission are calculated for a spatial reticular dome. The mass of the waste with respect to the mass of the stock, Mwaste/Mstock, is evaluated by adopting both the cutting Stock approach and the traditional approach. The former leads to a waste saving that is almost twice that obtained from the latter. However, no significant differences in terms of carbon emission can be observed by comparing the two approaches.

Open Access: Yes

DOI: 10.3233/ATDE240578

Stiffness Ratio Evaluation of Steel Exoskeletons Through Performance-Based Optimal Design

Publication Name: Advances in Transdisciplinary Engineering

Publication Date: 2024-01-01

Volume: 59

Issue: Unknown

Page Range: 438-445

Description:

Among the various seismic retrofitting techniques, steel exoskeletons are distinguished by their non-invasive nature. However, only a few consolidated methodologies have been proposed for their design. The approach of several standard codes is based on the classification of elements according to their relative stiffness. In this way, a ratio between the stiffness of the exoskeletons and that of the building is taken as the main design parameter. In this study, a performancebased design approach was employed, with the inter-story drift of the building as the performance target. A sensitivity analysis was conducted to assess the impact of different inter-story drift thresholds on the structural behavior of the buildingexoskeleton system. For each threshold, an optimization process was conducted to identify the optimal number of exoskeletons, their placement around the building, and the dimensions of their elements. Finally, the stiffness ratios were determined for each optimal configuration and were compared to the threshold provided by the regulations. This comparison yielded interesting insights into the differences in the approaches.

Open Access: Yes

DOI: 10.3233/ATDE240577

Model Calibration of High Damping Rubber Bearings: A Preliminary Mass Production Reliability Study

Publication Name: Advances in Transdisciplinary Engineering

Publication Date: 2024-01-01

Volume: 59

Issue: Unknown

Page Range: 389-397

Description:

Over the past decade, Building Isolation Systems (BIS) have gain significant relevance due to their ability to reduce horizontal acceleration and interstory drifts in structures. Since the 1950s, researchers have focused on developing numerical models to simulate the dissipative behavior of High Damping Rubber Bearings (HDRB) in parallel major earthquake events have highlighted the need for BIS devices in medium and large-scale infrastructure, accentuating the need for further research into accurate models and adding the pressing interest in variability of mass-produced HDRB parameters. This study presents initial results from an identification process using two numerical models, validated using experimental tests at the SISMALAB laboratory. The experimental data involved eight samples subjected to compression forces and horizontal displacement. Optimal values were obtained through a Genetic Algorithm optimization process, minimizing discrepancies between experimental and numerical response. Preliminary variability analysis was conducted on data from 20 independent iterations over the eight samples.

Open Access: Yes

DOI: 10.3233/ATDE240571

Preliminary Study on the Optimal Calibration of High Damping Rubber Bearings

Publication Name: Lecture Notes in Civil Engineering

Publication Date: 2025-01-01

Volume: 770 LNCE

Issue: Unknown

Page Range: 226-239

Description:

Seismic isolation emerged as an efficient technology for seismic protection. It has been proven to simultaneously reduce inter-story drift demands and horizontal accelerations in buildings when properly implemented. Since the 80s, several numerical models appeared in literature to simulate the dissipative behaviour of High Damping Rubber Bearings (HDRB) devices under different acting scenarios. Despite the efforts provided by several authors to reproduce the real behaviour of such devices through the definition of efficient numerical models, the variability of laws’ parameters in the mass-production series of devices should receive further investigations. This research presents the preliminary results pointed out by an identification procedure of no.2 existing literature models with an increasing level of computation effort. The reliability of the numerical outputs and the goodness of each numerical model have been demonstrated by comparing them with experimental tests obtained from the SISMALAB laboratory. Experimental data are composed of no. 5 samples of the same devices, subjected to both compression forces and horizontal displacement under sinusoidal cyclic deformation. The optimal values of each device have been obtained by performing an optimization process where the difference between experimental and numerical behaviour has been minimized. The well-known Genetic Algorithm has been chosen for this purpose.

Open Access: Yes

DOI: 10.1007/978-3-032-08407-1_20

Steel Exoskeletons for the Seismic Retrofit of an Existing RC Building: Optimal Design and Life Cycle Assessment

Publication Name: Lecture Notes in Civil Engineering

Publication Date: 2025-01-01

Volume: 770 LNCE

Issue: Unknown

Page Range: 214-225

Description:

The growing need for structural, energetic and architectonic refurbishment of the existing structures led to the emergence of alternative retrofitting techniques. Among them, steel exoskeletons stand out for their non-invasive and time-efficient nature, especially in cases where the relocation of the building’s activities is not allowed. In this research, the optimal exoskeleton configuration, in terms of number of exoskeletons and their position around the building, along with the sizing of their constituent elements, has been obtained through an optimization process. The optimization tool is based on a Genetic Algorithm with the aim of weight minimization, including as constraints a maximum allowable inter-storey drift for preserving the elastic behavior of the existing building, and the structural safety of the exoskeleton members. Two exoskeleton typologies were selected as case studies, employed for the retrofitting of an existing RC moment-resisting frame building. Furthermore, Life Cycle Assessment analyses were conducted on the optimal configurations considering two materials: steels with high and low percentages of recycled materials. The results yielded interesting insights into the structural performance of both exoskeleton typologies, as well as into the environmental characteristics of both studied materials.

Open Access: Yes

DOI: 10.1007/978-3-032-08407-1_19

Integration of Life Cycle Assessment in Structural Optimisation of Steel Structures

Publication Name: Lecture Notes in Civil Engineering

Publication Date: 2025-01-01

Volume: 770 LNCE

Issue: Unknown

Page Range: 181-190

Description:

Lowering environmental impacts has lately been a critical objective of structural optimisation due to the significant amount of greenhouse gas (GHG) emissions in the civil engineering sector. This work introduces a Life Cycle Assessment (LCA) based multi-objective optimisation framework for the optimal design of mixed steel-timber structures by varying the building design’s size, shape, and topology. The study’s novelty stems from the integration of an environmental objective function in the early design process, based on LCA methodology and standard environmental indicators, and the definition of a structural target function where a penalty-based approach is implemented for reducing structural complexity in situ. The structural cost and the Global Warming Potential (GWP) are the objective functions of the optimisation problem. The analysis outcomes reveal that minimising the number of connections as well as moving towards timber-steel solutions represents the key aspect to achieve a sustainable and effective design of spatial truss structures.

Open Access: Yes

DOI: 10.1007/978-3-032-08407-1_16