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CONTENTS
Volume 29, Number 4, October 2025
 

Abstract
Damping modification factor (DMF) is utilized in seismic design codes for computing high damping response spectra from their 5%-damped counterpart. These high damped response spectra are used for designing buildings with base isolation and supplemental damping devices. The current research aims at investigating DMFs derived from spectrum-compatible ground motions. Two ground motion datasets were selected and scaled from the PEER database using the two types of spectra in the current Egyptian code as target spectra. DMFs were derived using the two ground motion datasets and represented by empirical equation with suitable coefficients for each dataset. The resulting DMFs were compared to Eurocode 8 (EC8) expression and previous studies. The mean exact DMFs for dataset (1) at periods between 1.5 and 3 s had very good agreement with EC8. For dataset (1) and at damping ratio of 10%, the empirical equation had excellent matching with previous expression derived from moderate earthquakes in Egypt. The results of this study have also assured that by decrease in magnitude of earthquake, the resulting values of DMF exhibit higher tendency to approach unity at longer periods. The approach of using spectrum-compatible ground motions to derive DMFs showed a reasonable efficiency and may be useful if local strong motion records are scarce.

Key Words
damping modification factor; Egyptian seismic code; scarce local records; seismic isolation; target response spectra

Address
Structures & Metallic Constructions Research Institute, Housing & Building National Research Center, Dokki, Giza, Egypt

Abstract
Numerous earthquakes worldwide cause significant loss of life and property, emphasizing the urgent need for earthquake-resistant structures. Many buildings in Türkiye built before the 2000s fail to meet modern seismic codes, posing serious risks. Strengthening or rebuilding high-risk structures is essential; however, detailed nonlinear analysis for all buildings is impractical due to time and cost. Rapid assessment methods help prioritize buildings needing detailed evaluation. This study investigates the seismic performance of an existing reinforced concrete building using the Simplified Lateral Mechanism Analysis (SLaMA) method, recommended by the New Zealand Society for Earthquake Engineering (NZSEE). Beam-column joint damage was assessed using the strength hierarchy approach. Strengthening alternative concrete jacketing and carbon fiber reinforced polymer (CFRP) plates—were evaluated through hand calculations, SeismoBuild, and FRP Designer software. Plastic hinge lengths were validated using experimental data. Seismic performance was also assessed in accordance with the Turkish Building Earthquake Code (TBEC 2018), based on plastic rotation demands and capacity comparisons. Concrete jacketing alone improved base shear by 2.4 times and increased the %NBS score from 39% to 54% in the X-direction but was insufficient to meet performance targets. With additional CFRP beam strengthening, the %NBS score exceeded 68%, satisfying NZSEE thresholds. According to TBEC (2018), the structure's performance level improved from "collapse prevention" to "controlled damage" only after both columns and beams were retrofitted. The SLaMA method effectively identified structural weaknesses and prioritized retrofit needs, while TBEC provided a rigorous framework for validating seismic performance improvements.

Key Words
CFRP; concrete jacketing; pushover analysis; seismic evaluation; SLaMA; strengthening

Address
Department of Civil Engineering, Dokuz Eylul University, Central Campus, Buca, Izmir, Türkiye

Abstract
Türkiye was shaken by the Kahramanmaraş earthquakes on February 6, 2023, which caused huge structural destruction. Large-scale loss of life and property occurred due to structural damage. These earthquakes, which are neither the first nor the last for Türkiye, have once again demonstrated that structural weaknesses are a factor in damages, as is the case after every earthquake. Many factors affecting the earthquake vulnerability of buildings are taken into account as parameters in the rapid assessment methods used for buildings. Within the scope of this study, the structural parameters specified in the simplified method used to determine regional risk priorities for reinforced-concrete structures in the Principles for Detection Risky Structures updated in 2019 in Türkiye were taken into account. Detailed information is given for each parameter taken into account in this method, and the structural damages that occurred in the Kahramanmaraş earthquake of February 6, 2023 are exemplified. The effect of each parameter in this rapid assessment method on the structural performance to be obtained for a reinforced-concrete building has been numerically obtained. A reduction coefficient was suggested as a result of structural analysis for the lack of building construction year for this method. A reduction coefficient of 15% was suggested for buildings built between 1975 and 1997, 10% for buildings built between 1998 and 2006, and 5% for buildings built between 2007 and 2017. In addition, the effect of concrete grade on structural analysis was evaluated based on different parameters.

Key Words
damage; earthquake; Kahramanmaraş; pushover analysis; rapid assessment; reinforced-concrete

Address
Department of Civil Engineering, Bitlis Eren University, Bitlis 13100, Türkiye

Abstract
In recent years, structural failures due to the loss of gravity load-bearing members have increased, emphasizing the need to design both seismic performance and progressive collapse resistance. The type of structural system, building configuration, and retrofitting strategies play a crucial role in mitigating progressive collapse. This study aims to compare the performance of reinforced concrete and steel structures to assist in selecting appropriate structural systems for future critical projects. In this research, nonlinear static pushover analysis using the Finite Element Method (FEM), based on the Unified Facilities Criteria (UFC) guidelines, was employed to evaluate the progressive collapse potential of two medium-ductility moment-resisting frame systems (one reinforced concrete and one steel structure) designed in accordance with the Uniform Building Code (UBC). ABAQUS was used to analyze the structures. The study assessed the structures and the influence of structural types on reducing the likelihood of progressive collapse. The results indicate that corner columns in both RC and steel structures exhibit higher displacements compared to other columns. Furthermore, the maximum displacement in the concrete structure was approximately 25 percent higher than in the steel structure. Consequently, the concrete structure demonstrates a lower capacity to resist progressive collapse compared to the steel structure. In contrast, the steel structure exhibits greater resistance to progressive collapse.

Key Words
finite element method; moment-resisting frame system; nonlinear static analysis; progressive collapse; steel and RC structures

Address
Amir Masoumi Verki: Department of Civil Engineering, Lakehead University, Thunder Bay, ON, Canada
Adolfo Preciado: Department of Habitat and Urban Development, Western Institute of Technology and Higher Education (ITESO), 45604, Tlaquepaque, Jalisco, Mexico

Abstract
The study recommends revising the Algerian seismic code (RPA) by introducing a new design spectrum based on real seismic data. The current code has shortcomings that may lead to underestimating seismic forces, risking structural safety. The proposed spectrum aims to offer a more accurate assessment of building behavior during earthquakes and aligns with the globally recognized performance-based design approach. The revision includes updates to formulas and parameters, as well as recommendations for improving spectrum accuracy. By utilizing Algerian seismic data, this approach is expected to provide results more relevant than international standards like FEMA and Eurocode 8. This work seeks to incorporate these enhancements into the Algerian code, replacing traditional methods and providing better protection against seismic risks.

Key Words
Algerian seismic code; demand spectra; seismic design spectrum; seismic zones

Address
L.D.G.M. Laboratory, Faculty of Technology, Department of Civil Engineering, University of M'Sila, University Pole, Bordj Bou Arreridj Road, M'Sila 28000, Algeria

Abstract
In this study, quasi-static cyclic loading tests were conducted to evaluate the in-plane structural performance of half-precast concrete slab-wall joints. Nine full-scale specimens were fabricated, with key test variables that include the system type, anchorage type, number of anchorage reinforcements, and slab type. The structural performance was assessed in terms of the lateral load-displacement behavior, maximum load capacity, stiffness retention ability, and energy dissipation capacity. The results showed that the monolithic reinforced concrete specimens exhibited superior performance compared to the half-precast concrete specimens. However, the half-precast concrete specimens exceeded the nominal shear strength requirements specified in ACI 318-19. Among the half-precast concrete specimens, the anchorage type and slab type had negligible effects on the overall performance, whereas an increase in the number of anchorage reinforcements unexpectedly resulted in degraded performance. Analysis of the local shear strength of the anchorage reinforcements revealed that those in the half-precast concrete specimens failed to achieve the intended shear capacity, primarily because of insufficient development length. Based on these findings, a modified nominal shear strength model incorporating the anchorage development length was proposed.

Key Words
cyclic loading test; in-plane structural behavior; precast concrete; reinforced concrete; slab-wall joint; structural performance

Address
Jae Hyun Kim, Cha-Young Yun, Hoseong Jeong and Min-Kook Park: Department of Architectural Engineering, University of Seoul, 163 Siripdae-ro, Dongdaemun-gu, Seoul 02504, Korea
Sun-Jin Han: Department of Architectural Engineering, Jeonju University, 303 Cheonjam-ro, Wansan-gu, Jeonju-si, Jeonbuk-do 55069, Korea
Kang Su Kim: Department of Architectural Engineering and the Smart City Interdisciplinary Major Program, University of Seoul, 163 Siripdae-ro, Dongdaemun-gu, Seoul 02504, Korea

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