Benjamin Labar

59125118900

Publications - 3

Assessing Local Site-Specific Response Spectra Based on Site Data in Gyor

Publication Name: Advances in Transdisciplinary Engineering

Publication Date: 2024-01-01

Volume: 59

Issue: Unknown

Page Range: 422-430

Description:

It is essential to understand seismic ground motion in order to understand how dynamically a structure responds to earthquakes. Due to variations in seismic loading, strong ground vibrations can damage structures to varying degrees. The different essential traits of powerful ground motions help explain this ground diversity during moderate to large earthquakes. This study mainly focuses on the comparison between ground motion parameters such as the Peak Ground acceleration (PGA), and local site spectra considering the design response spectrum and site-specific response spectra of varying soil profiles in Gyor. Multichannel analysis of Surface Waves (MASW) data from eleven different places in Gyor were considered and analyzed using the 1-dimensional response analysis software, STRATA, and a detailed comparison was carried out between the different site locations in terms of PGA, and local site spectra. The result revealed the sites with the highest amplifications based on peak ground values of acceleration, velocity, and displacements. With 1-dimensional STRATA software, peak ground acceleration profiles, and response spectrum results are obtained and compared to Eurocode 8 standards.

Open Access: Yes

DOI: 10.3233/ATDE240575

Enhancing Seismic Performance: A Comprehensive Study on Masonry and Reinforced Concrete Structures Considering Soil Properties and Environmental Impact Assessment

Publication Name: Advances in Civil Engineering

Publication Date: 2024-01-01

Volume: 2024

Issue: Unknown

Page Range: Unknown

Description:

Approximately 20,000 people are killed annually on average by building and infrastructure collapses and failures caused by seismic activities. In earlier times, seismic design codes and specifications set minimal requirements for life safety performance levels. Earthquakes can be thought of as recurring events in seismically active areas, with severity states ranging from serviceability to ultimate levels. Buildings designed in accordance with site-specific response spectra, which take into account soil properties based on ground motion amplification data, are better at withstanding such forces and serving their design purposes. This study aims to investigate the site response of reinforced and masonry buildings, considering the effect of soil properties based on the amplification of ground motion data, and to compare the life cycle assessment of the buildings under consideration based on the design and the site-specific response spectrum. In terms of soil properties and site-specific response spectra, STRATA is used to determine the site-specific response for the considered locations for a return period of 475 years for 100 realizations based on the randomization of site properties. For structural analysis, AxisVM software, which is a compatible finite element analysis, is used for building design and analysis, generating comparative results based on the design- and site-specific spectra. To determine and identify potential failures in the model, response spectra were applied to understand the difference in horizontal deflection in two different instances (for elastic design- and site-specific spectra). After building design and analysis is performed, a life cycle analysis in terms of environmental impact assesments using OpenLCA and IdematLightLCA is done. This is done to ascertain the additional expenses in terms of ecocosts and carbon footprints on some failed elements in the structure which are required to make the buildings more resilient when the site-specific response spectrum is applied and to compare the potential economic losses that may occur based on ecological costs. The study presents a comprehensive investigation into the seismic response of masonry and reinforced concrete buildings in Győr, Hungary, incorporating advanced geophysical techniques like multichannel surface wave (MASW) and structural analysis software, AxisVM. Additionally, tailored retrofitting strategies are explored to enhance structural resilience in seismic-prone regions. Significant ground amplifications in soil properties across different profiles are revealed, emphasizing the effectiveness of these strategies in reducing structural deflection and improving resilience. Highlights of the results are observed where the site-specific response spectra are higher than the EC8 design response spectrum. Furthermore, the research underscores the substantial environmental impact, considering both ecocosts and CO2 emissions associated with retrofitting measures, highlighting the importance of sustainable structural interventions in mitigating seismic risks.

Open Access: Yes

DOI: 10.1155/2024/4505901

Cooling Degree Day Trends and Their Implications for Building Thermal Design and Thermal Fatigue Loading in Lagos, Nigeria

Publication Name: Buildings

Publication Date: 2026-07-01

Volume: 16

Issue: 13

Page Range: Unknown

Description:

Buildings in Lagos require mechanical cooling year-round, with air conditioning accounting for up to 80% of residential electricity consumption. Despite this, the Nigerian Building Code (NB 485:2017) still references 1990s thermal design data, creating a growing mismatch between design assumptions and actual thermal conditions. Compounding background warming and an intensifying urban heat island have widened this gap considerably, yet no study has linked long-term cooling demand trends to quantified engineering design shortfalls for any Nigerian city. This study presents a 35-year cooling degree day (CDD) trend analysis for Lagos (1990–2024), derived from 12,784 daily temperature records at four engineering base temperatures (22 °C, 23.3 °C, 26 °C, and 28 °C) respectively. Trends are detected using the Mann–Kendall test with Trend-Free Pre-Whitening and Sen’s slope as the magnitude estimator. Significantly increasing CDD trends are confirmed at three base temperatures, with a Sen’s slope of +4.55 °C·days yr−1 at the primary design reference of 23.3 °C (p < 0.01). Structural break analysis identifies 2015 as the transition into a persistently above-baseline thermal regime, with mean CDD in the most recent sub-period exceeding the 1990–2001 design baseline by up to 50% at higher base temperatures. The detected trends are translated into three engineering gap analyses: required envelope U-value trajectories, an HVAC capacity undersizing index, and annual thermal cycling frequency as a structural fatigue proxy. Results show that the dominant uninsulated sandcrete typology fails ASHRAE 90.1-2019 Zone 1A prescriptive limits throughout the study horizon, installed HVAC systems are already operating in the engineering caution zone, and façade fatigue loading has intensified markedly since 2015. To the author’s knowledge, this study is the first to couple a statistically robust long-period CDD record for Lagos with code-referenced design gap figures, providing a replicable framework for climate-adaptive building code revision across similar hot–humid climates in sub-Saharan Africa.

Open Access: Yes

DOI: 10.3390/buildings16132557