https://www.bese.ir/ Bulletin of Earthquake Science and Engineering en daily 1 Tue, 23 Sep 2025 00:00:00 +0330 Tue, 23 Sep 2025 00:00:00 +0330 https://www.bese.ir/article_717482.html The structural assessment of existing masonry buildings often requires reliable estimation of their compressive strength. However, conventional experimental methods such as testing full-scale prisms or wallettes are highly invasive, time-consuming, costly, and impractical for in-situ evaluation of historic or existing structures. Alternative techniques like the flat-jack test provide only elastic-range data and fail to capture post-peak softening behavior or ultimate compressive capacity. In this context, core drilling emerges as a promising minimally invasive approach, enabling the extraction of small cylindrical samples (masonry cores) for laboratory testing while preserving the integrity of the parent structure. Despite its potential, the interpretation of core compression tests remains challenging due to complex stress states, size effects, and the heterogeneous nature of masonry materials. This study presents a comprehensive numerical investigation into the compressive behavior of masonry cores compared to standard prismatic specimens, using advanced finite element modeling. A three-dimensional continuous micro-modeling strategy is employed, explicitly representing both bricks and mortar without interface elements. Two sophisticated constitutive models are implemented and compared: (1) the widely used Concrete Damage Plasticity (CDP) model available in Abaqus, and (2) an enhanced Multi-Laminate Model (MLM) based on the angular decomposition of stress space. The MLM is specifically upgraded to account for biaxial tensile-compressive stress states in bricks and triaxial confinement effects in mortar key mechanisms governing masonry failure under compression. The MLM incorporates a fracture-energy-based softening law and separates stress into volumetric and deviatoric components, applying the latter to multiple micro-planes (66 in this study) to inherently capture the pronounced anisotropy and directional dependency of quasi-brittle materials after cracking. In contrast, the CDP model relies on isotropic damage and invariant-based yield surfaces, which may inadequately represent the true 3D stress interaction between masonry constituents. Both models are rigorously calibrated using experimental data from the literature, particularly from compression tests on masonry prisms and cores conducted by Pelà et al. (2016). Calibration involves determining path-dependent parameters for triaxial compression and biaxial tension-compression states through single-element simulations with appropriate boundary conditions. The models are then validated against three benchmark cases: (i) a five-brick prism, (ii) a 150-mm diameter masonry core under axial compression, and (iii) a full-scale shear wall tested at Eindhoven University. Results demonstrate that the enhanced MLM accurately predicts both the peak compressive strength and the failure mode including vertical splitting in bricks and hourglass-shaped crushing closely matching experimental observations. The model correctly estimates the lateral confining stress in mortar (≈0.65 MPa), aligning with theoretical expectations from Hilsdorf’s framework. In contrast, the CDP model significantly overestimates strength (by up to 86% in prisms and 36% in cores), primarily due to unrealistic confinement assumptions and inability to capture directional tensile failure in bricks. Furthermore, the MLM successfully reproduces the load–displacement response and crack patterns of the Eindhoven shear wall under combined vertical and lateral loading, confirming its robustness for practical structural analysis. This study confirms that core testing, when interpreted through advanced, physically consistent numerical models like the enhanced MLM, offers a viable, minimally destructive method for assessing the compressive behavior of existing masonry. The proposed approach provides deeper insight than laboratory tests alone delivering full-field stress and strain distributions and outperforms conventional modeling techniques in accuracy and physical fidelity.  https://www.bese.ir/article_718471.html The collapse of a building during an earthquake event signifies that some of the existing structural systems designed in compliance with the current code requirements are still unable to withstand the dynamic loads induced by earthquakes. Hence, understanding the behavior of buildings in high seismic hazard areas during severe earthquakes is crucial for preventing structural failures.Numerous studies over the past few decades have delved into the behavior of irregular buildings, highlighting that the irregularity of a building can lead to varied demands depending on its ductile deformation capacity under lateral loads, potentially resulting in suboptimal use of materials in load-resisting members. Additionally, seismic loads may affect the lateral load-bearing members differently due to the building's irregularity.For high seismic hazard regions, Iran's Seismic Code (Standard 2800) specifies the significant impact of accidental eccentricity in mitigating the adverse effects of torsion on the collapse of irregular buildings. However, the influence of accidental torsion on the collapse performance of torsionally flexible buildings requires further exploration. To this aim, the present study investigates the collapse performance of asymmetric models with flexible torsional behavior in accordance with FEMA-P695 guidelines, particularly in special reinforced concrete moment frame (SMF) buildings. The collapse margin ratio (CMR) is applied as a measure of the models' collapse performance. The proposed SMF buildings are designed considering various conditions of stiffness distribution. Then, the collapse behavior of asymmetric models is assessed by implementing an eccentricity that characterizes the accidental torsion effects.The modeling and the analysis are carried out using OpenSEES software, in which the plastic behavior of the members is simulated using the concentrated plasticity method developed by Ibarra et al. The collapse mechanism of the models is scrutinized for different states of eccentricity to offer a comprehensive understanding of the accidental torsion effects on the collapse of torsionally flexible models. Utilizing the incremental dynamic analysis (IDA), the proposed collapse criterion is calculated, where the seismic intensity measure in dynamic analyses is the spectral acceleration at the fundamental lateral mode period. The commencement of instability in the building models is recognized by the concurrent formation of plastic hinges at the ends of the frame components in one or more floors. This instability criterion is overseen and managed by a processor programmed in MATLAB. The second criterion of the collapse occurrence is the inter-story drift ratio of building models, which is considered to be 10% of the story height.The results demonstrate that by altering the position of the center of mass in the models, the safety margin against the collapse is bolstered by an average of 10%. This enhancement appears to be independent of the location of the center of mass relative to the center of rigidity in the plan. These findings raise pertinent questions about the significance of design accidental torsion criteria in this specific category of structures. However, there is a need to conduct additional studies before making any regulatory recommendations. For torsionally flexible models, the dominant mode of motion (i.e., the torsional mode) will have a great kinetic superiority with increasing eccentricity. As a result, the ro-le of that mode in absorbing earthquake energy will be greater than that of the translational modes. Accordingly, the damages that are directly caused by relative displacements in the direction of earthquake load will decrease with increasing distance of the center of mass from the center of rigidity, resulting in an increase in the safety index.The results also demonstrate that the distribution of relative lateral displacements in torsionally flexible models is consistent with the distribution of plastic hinges. Interestingly, a distinct pattern of failure propagation has been identified for these structures, contrasting with torsionally stiff buildings. https://www.bese.ir/article_718018.html Today, with the growth of oil and gas industries, the growth of accidents caused by the effect of natural hazards on these industries is also observed. This category of technological accidents caused by natural hazards is called NaTech events. The severity of the damages caused by these events clarified the need for communities and researchers to evaluate and control this category of events or mitigate their risks. Quantitative risk assessment of NaTech events is one of the methods and approaches adopted for this purpose. In this method, the vulnerability of structures is estimated by using fragility curves obtained from different methods. Numerical analysis methods are one of the most widely used methods for calculating fragility curves. The fragility curve of the elements and components of a plant is conventionally calculated based on the characteristics of their construction time using various numerical analyses. While generally, in calculating fragilities, the effect of aging of structures on fragility and subsequently their effect on the results of risk assessments of industrial plants are not taken into account. Most of the studies conducted to calculate the fragility of structures are based on the basic characteristics and properties of the structures. This is while the structures lose their original features due to the age deterioration. From a seismic analysis point of view, aging or deterioration may affect dynamic properties, structural response, strength or capacity, failure modes, and failure initiation locations. The aging of the equipment affects the seismic fragility curve in two ways: on the average capacity and on the uncertainties, the former being potentially more important. Deterioration, often seen as a reduction in cross-sectional area or cracking, reduces the strength (equipment) and thus exacerbates brittleness. It is obvious that the fragilities variation clearly affects the risk assessment results of oil and gas industries. The purpose of this study is to investigate the effect of deterioration caused by the aging of tanks on the quantitative seismic risk results in oil and gas industries. In this study, a storage plant has been selected as a case study, and while introducing the OpenSRANE software, which is a flexible and extensible software, calculations and evaluations related to the seismic risk of NaTech events of the said plant have been carried out using the mentioned software or platform. By assigning the fragility corresponding to different deterioration ages, the seismic risk of NaTech events has been calculated for each age, and the results for different ages have been compared. It is worth mentioning that due to not having enough information about the effect of aging of structures on the relevant probit functions, the calculations have been done ignoring the mentioned effect, and the evaluation of this effect is left to future studies. https://www.bese.ir/article_718822.html Iran is considered one of the most seismic countries in the world due to its location in the Alpine-Himalayan seismic zone, its geological and tectonic location, the presence of numerous active faults in its various parts, and the continuous occurrence of micro-earthquakes. After the occurrence of destructive contemporary earthquakes in Iran and the extensive destruction of urban and rural housing, various approaches have been taken into consideration by planners and policymakers in order to rebuild housing after the disaster. The purpose of this article is to evaluate the correct and optimal management of housing reconstruction after an earthquake in four earthquakes that occurred in Iran, namely the Rudbar-Manjil earthquake (1369), the Bam earthquake (1382), the Ahar-Varzaghan earthquake (1391), and the Sarpol-e Zahab earthquake (1396). The basis of the evaluation in this article is the "Management cycle of housing reconstruction after the earthquake" model, which includes four main criteria groups and 17 weighted criteria. These factors play an effective role in reducing financial, managerial, and executive problems and achieving desired results in optimal reconstruction. The criteria are categorized in 4 main groups of “Coordination and organizational affairs”, “Technical and engineering affairs”, “Economic and financial affairs”, and “Social participation and community affairs”. Prioritized by experts, the factors of “Economic and financial affairs” and “Coordination and organizational affairs” are recognized as the most influential, followed by the next priorities, “Technical and engineering affairs” and “Social participation and community affairs”.In this research, the quantitative evaluation is in the form of a questionnaire through a survey of the community of experts and specialists. In this way, 68 experts in the field of post-disaster reconstruction from different organizational, academic, and engineering levels participated in this evaluation based on the AHP method.The interviewees were asked to categorize their opinion on the level of realization and implementation of 17 effective criteria in post-disaster housing reconstruction during the selected earthquake reconstruction program in five qualitative levels (from 1 to 5). In this survey, score 1 indicates the lowest degree of realization of the criterion, and score 5 indicates the highest degree of realization of the post-accident reconstruction criterion. The answers given to each question were averaged. After conducting statistical analysis and investigations on the results of participants' opinions in the form of two questionnaires, the performance of housing reconstruction in each of the four selected earthquakes is close to each other in the range of 0.4 to 0.5. That is, there has been no significant progress in reconstruction since the Rudbar-Manjil earthquake to Sarpol-e Zahab. The Ahar-Varzaghan earthquake of 2011, with an average score of 0.470, had the best performance, and the Sarpol-e Zahab earthquake of 2016 with an average score of 0.415 had the weakest reconstruction performance among other disasters. Of course, with careful analysis and calculations, it was observed that the opinions of the respondents were closer to each other in Ahar-Varzaghan, and the dispersion of opinions was greater in Sarpol-e Zahab. https://www.bese.ir/article_717484.html In order to investigate the behavior of the structure during the earthquake and after it ends, the design engineers examine the performance criteria, including the nonlinear performance of parameters including force, deformation, and yielding mechanism of the structure. Structural design criteria include lateral forces and resistance of members, structural yielding mechanism, story displacement, and performance level that should be checked during structural design. In the plastic performance of the structure, the target relative displacement criteria and the yield mechanism are very important in investigating this performance zone. Among the very important factors in the nonlinear zone are plastic hinges, which investigated in the present study in 10 types of modern braces. For this purpose, a reliable and validated questionnaire was compiled using the opinions of experts in the field of structural engineering. This questionnaire has 6 criteria, the opinions of 70 university professors and PhD students were collected by it. In creating the hierarchical research tree, widely used models including goals and criteria were used. The initial criteria were determined with the help of library studies and the opinions of structural engineering experts. The 6 criteria include "Base shear force", "Pushover curve", "Story displacement and drift", "Bending and shear forces and Torsional anchor", "Plastic hinges" and "Modal periodic time and frequency". Using Cronbach's alpha formula for unlimited societies, the validity of the questionnaire was determined, which was determined as 0.9014. Therefore, questionnaires have high reliability in grades and questions. Then, the average scores collected from the statistical population were entered as primary data in the Expert Choice software. With the hierarchical analysis method in this software, the input data were weighted and finally prioritized. Then, 2D steel frames that have 10 steel braces including Diagonal, Gate, V, Inverted V, Knee, Rhombus, Eccentrically with lateral horizontal link beam, Zipper, Cross, Eccentrically with middle horizontal link beam were modeled by SAP2000 software. The performance of all bracing systems was compared with a steel moment frame (SMF). The steel structures have 4 and 8-story, all the structures were analyzed by nonlinear static analysis (pushover analysis). The results showed that the plastic hinge criterion with an impact factor of 0.424 is the most important parameter of the structure's performance in the plastic zone. Also, the eccentrically braced frame with the middle horizontal link beam (in the 4-story structure) had a total of 33 plastic hinges and the zipper brace (in the 8-story structure) had a total of 49 plastic hinges, which increased by 60.98% and 48.04%, respectively. The plastic hinges were compared to the average of the total braces. The use of each of the 10 mentioned braces in 4 and 8-story structures reduces displacement by 33.65% and 19.27%, respectively, compared to the SMF. https://www.bese.ir/article_717485.html Since the 1960s, seismic vulnerability studies of buildings have gained paramount importance, driven by major earthquakes such as Niigata (1964) and San Fernando (1971), which exposed critical deficiencies in structural performance. These events spurred the development of diverse assessment methods, ranging from empirical fragility curves to advanced analytical simulations. Among the simplest and most cost-effective techniques is ambient vibration analysis using microtremors (Nakamura's HVSR method, 1989), which estimates dynamic characteristics like fundamental periods via horizontal-to-vertical spectral ratios; however, its reliability has long been questioned compared to strong-motion records due to lower excitation amplitudes.This study rigorously evaluates the feasibility of microtremor-based analysis for seismic vulnerability assessment by directly comparing it against strong ground motion results. A comprehensive inventory of 54 medium-rise steel buildings was analyzed, comprising moment-resisting frames (MRFs: M335S1 to M655S3) and concentrically braced frames (Br335S1 to Br1255S3), spanning 3 to 12 stories across three soil types (classified per Iranian Standard 2800-14). Numerical models were meticulously developed in ETABS for linear elastic analyses and OpenSEES for nonlinear time-history simulations, incorporating soil-structure interaction (SSI) effects via DEEPSOIL profiles and Raychowdhury et al. (2015) relations.Inter-story drift ratios were computed under real earthquake accelerograms from the PEER database (e.g., Kocaeli 1999, Northridge 1994) and synthetic microtremor excitations calibrated with SeismoSignal. Vulnerability indices were then derived using HAZUS-MH MR5, mapping drifts to damage states (Slight, Moderate, Extensive, Complete) across spectral acceleration levels (S1L/M/H, S2L/M/H) for Design Basis Earthquake (DBE) and Maximum Considered Earthquake (MCE) scenarios. PGV/PGA ratios (0.8-1.2) validated spectral compatibility per FEMA 365.Results reveal an 80-90% concordance between microtremor-derived drifts and strong-motion predictions, with taller structures (8-12 stories) showing higher sensitivity to SSI and exhibiting Extensive/Complete damage under MCE (probabilities up to 0.04). Braced frames generally outperformed MRFs in DBE but converged at MCE. This validates ambient vibrations as a practical, low-cost alternative for large-scale screening, particularly in developing regions like Iran.The study proposes an optimal frequency band (0.35-0.58 Hz for HVSR peaks) for future applications on similar steel frames, alongside recommendations for integrating HAZUS with Iranian code updates (e.g., ATC-40 equivalents). Such hybrid approaches enhance post-earthquake rapid visual screening and retrofit prioritization. https://www.bese.ir/article_717487.html Considering the high seismicity of Iran and the suitable performance of modern lateral force resisting systems, this paper investigates the seismic behavior of steel structures equipped with linked- column- frame system (LCF) under single and consecutive near- field earthquakes. In this regard, steel structures with 4, 6, and 8 story (the usual number of stories in Iran) containing dual LCF with shear performance for linked beams have been designed based on 2800 standard and implemented in Opensees software. After verification of studied models with the valid researches such as Golestani et al., (2023) – one 3 story steel frame with 2.0 m linked beam considering American sections – with comparison of periods and Push over curves, nonlinear dynamic analysis have been performed under single and consecutive near field earthquakes with and without pulse. In this study, the proposed near filed records with and without pulse by FEMA356 have been used and “back to back” or “Repeated” method has been selected to generate the successive shocks. For this purpose, first shock is considered as second shock after 30 seconds time gap with zero acceleration. It should be noted that the seismic scenarios are scaled based on 2800 standard considering the fundamental period of the studied models. The results indicate that as the number of stories increases, the structural damage and maximum displacement - especially for studied frames exposed to consecutive earthquakes without pulse - increase. In this study, for evaluation of the performance of linked beams, steel frames with 4 stories have been designed and analyzed with shear and flexure performance. The results show that the average maximum relative displacement of the roof is 4% and 3.9%, the average relative displacement damage index is 1.2% and 1.4%, respectively, for the 4-story frame containing linked beams with shear and flexure performance under successive near fault records without pulse. Similarly, in the absence of pulses in the consecutive seismic scenarios, Raphael's damage index for the above mentioned 4 story frame has been reported as 78% and 80% considering the shear and flexure linked beams. In this study, a comparison has been made between 4, 6 and 8-story frames, and the results corresponding to the maximum relative displacement of the roof are 4% for the 4-story frame, 4.3% for the 6-story frame, and 5% for the 8-story frame. In the following, the average value for relative displacement damage index is reported 1.3%, 1.4% and 1.7% for 4, 6 and 8 story frames in critical case. Generally, the caused damages by seismic sequence phenomenon are about 16% more than the single case. The average ductility damage index for the most critical mode – successive shocks without pulse – for 4, 6 and 8 story frames, is about 174%, 226% and 281%, respectively. In general, it can be claimed that seismic sequence phenomenon can increase the damage index compared to the single case because of the accumulation of damages caused by the previous earthquakes and the lack of sufficient opportunity to restore the structure to its initial equilibrium state, and the consideration of this phenomenon in the analysis and design of structures seems necessary, despite the proposed methodology in the seismic regulations. https://www.bese.ir/article_717488.html The importance of bridges in urban and intercity transportation systems is well recognized. However, the geometric irregularity of bridges can significantly exacerbate their performance during earthquakes. This issue has led to the development of new and complementary regulations in recent years. Environmental constraints, such as the topography of the construction site, are crucial factors contributing to these irregularities, resulting in complex dynamic behaviors. Notable instances of bridge irregularity include unequal stiffness of adjacent and non-adjacent columns, unequal span lengths, and the presence of curves in the plan. One of the most significant factor contributing to these irregularities is the unequal height of columns, which makes shorter columns more prone to damage due to their higher stiffness. Furthermore, the concentration and penetration of chloride ions into the concrete environment, known as chloride-induced corrosion, is a common environmental factor that deteriorates the properties of column materials. This phenomenon can increase the vulnerability of reinforced concrete bridges during earthquake exitation.In this study, seven RC bridge configurations were evaluated. These configurations include one regular configuration, three configurations with varying column heights, and three configurations with varying span lengths. All bridges have prestressed concrete box decks and four spans and were designed using the CSi Bridge software. After verifying the design accuracy in both OpenSees and CSiBridge, ensuring correct distribution of mass and stiffness as well as static force distribution, the nonlinear behavior of the columns was validated through cyclic analysis, and the analysis parameters were calibrated using experimental sample results. According to AASHTO recommendations for elastic deck behavior, elastic beam-column elements were used to model the deck. The nonlinear behavior of the columns was modeled using fiber formulations and force beamColumn elements. Unlike complex formulations, force beamColumn elements model the actual structural behavior and provide more accurate results. For the initial validations, the bridge columns were modeled using elastic beam-column elements. To model the effects of column behavior degradation, fatigue materials in the OpenSees software were used, which simulate the fatigue of longitudinal reinforcements. Additionally, during the bridge modeling process, necessary values and parameters were calibrated to best account for the effects of longitudinal reinforcement fatigue. Subsequently, nonlinear time-history analysis considering various percentages of reinforcement corrosion was performed in OpenSees software. Rayleigh damping was used in all analyses with a value of 5%. The assumed corrosion percentages were 0, 10, 20, 30, 40, and 50 percent, and the abutments were modeled using zero-length nonlinear springs. In relation to modeling chloride corrosion effects, degradation of mechanical properties of the concrete cover, degradation of mechanical properties of the concrete core, degradation of bond strength between steel and concrete, degradation of mechanical properties of longitudinal and transverse reinforcements, longitudinal reinforcement slip, and longitudinal reinforcement fatigue were all modeled. Finally, the results of the time-history analysis were extracted in the form of maximum column drifts and the maximum drift observed in each model under 11 applied records. The vertical earthquake component was neglected in this study, and all records were applied in the longitudinal and transverse directions. The results indicate that increasing the corrosion percentage leads to an increase in column drift in both longitudinal and transverse directions. Additionally, in all irregular bridges, the sensitivity of drifts to corrosion percentage increased, and the drifts increased at a faster rate. In irregular bridges with unequal span lengths, as corrosion exceeds 30 percent, the rate of increase in transverse drift in all these bridges increased, with the increase rate being up to 6 times higher. https://www.bese.ir/article_717658.html Today, many dangers threaten building structures. Many abnormal loadings are not considered in the design of structures. The sudden removal of the column can occur as a result of mistakes caused by construction, explosion, impact or any other unusual cause in the structure. In steel structures, steel frames, as one of the main components of the structure, play an important role in the safety and durability of the structures. However, progressive failure in steel frames causes problems for structures due to arbitrary deformation. The purpose of this research is to investigate the effect of using converging braces in increasing the durability and safety of steel structures against progressive failure. In this research, SAP2000 software and non-linear analysis have been used in terms of the effects of non-linear geometric deformations, in order to model and examine the behavior of connections in numerical analysis. By examining 3, 8 and 12 story structures with and without column removal, it was determined that they were modeled with three types of cross braces, seven and eight. The results showed that in the model of the 3-story structure with cross bracing, the displacement was reduced by 63% compared to the model without braces and without progressive failure. Also, in the model of the 8-story structure with cross braces, there was a 38% reduction in displacement compared to the model without braces and without progressive failure, and in general, the 12-story structure model with cross braces had a 23% reduction in displacement compared to the model without braces and without progressive failure. .Research in the field of using converging braces in steel structures, due to its importance in increasing the strength and safety of structures, has been noticed. Considering that the research topic of investigating the effect of convergent braces on the strength of steel frames in progressive failure is one of the most important topics in the field of steel structures. Considering that progressive failure in steel frames can cause serious risks for people and high damages for structure owners, the use of converging braces is considered as an important solution to prevent progressive failure. In addition, considering that the use of converging braces in steel structures requires high costs, determining cost optimization and optimal use of converging braces is also one of the important goals of this research project. By determining the optimization of costs and the optimal use of converging braces, it is possible to reduce the costs of building the structure and increase the efficiency of using converging braces in steel structures. With the studies conducted and the investigations carried out in the field of the possibility of the vulnerability of today's buildings in the cities against progressive deterioration and that the majority of the existing buildings are not capable of dealing with such a phenomenon and are vulnerable to progressive deterioration, so the purpose of this conclusion The message is to seek to improve this situation by providing a solution and to help those buildings that have been built, but in their designs, the characteristic loading of progressive failure has not been included. In this project, three-, eight-, and twelve-story steel buildings with bending frame were evaluated with the help of SAP2000 software and in three-dimensional form with the influence of various factors such as the type and shape of converging braces, and these evaluations were done with the help of non-linear static analysis. And the results are presented in the form of tables and diagrams, which include the formation of plastic joints of the members in all three structures, comparing the sturdiness of the structures, checking the vertical displacement of the desired top node and comparing between different models, as well as checking and controlling the relative lateral displacement of the floors.1. Investigating the effect of using converging braces in increasing the strength and safety of steel structures against progressive failure.2. Determining the optimal type, shape, and converging braces to increase the strength of steel frames and prevent progressive failure.3. Cost optimization and optimal use of converging braces in steel structures, in order to reduce the cost of building the structure and increase the efficiency of using converging braces in steel structures.4. Investigating the changes in the behavior and strength of steel structures using converging braces in progressive failure.5. Using numerical simulations with the help of SAP2000 software, in order to determine the best type and shape of optimal convergent braces.Today, the discussion of passive defense and increasing the flexibility and strengthening of structures against explosions, collisions and impacts is one of the main concerns of government organizations around the world, including Iran. It has progressed to failure. https://www.bese.ir/article_718473.html The railway is one of the main pillars of transportation in any country, and it plays an essential role in the movement of passengers and goods and has significant economic and social effects. Earthquakes, as one of the unpredictable natural hazards, can cause long-term blocking of the rail transport network and financial and human losses. From this point of view, it is imperative to maintain the safety and status of stations, bridges, tunnels, and railway lines as the most vital rail transportation infrastructure. Razavi Khorasan province is one of the provinces prone to earthquakes in Iran. The railway lines of the Khorasan General Directorate of Railways are also of considerable importance in Iran's railway network from the perspective of moving a large number of passengers to Mashhad city and the transit of goods through Sarakhs International Railway Terminal. Therefore, it is necessary to strengthen the infrastructure of the railway network against earthquakes to maintain safety. Considering the economic and operational limitations, evaluating and prioritizing the seismic retrofitting of rail transport infrastructure is necessary, which is regarded as the primary goal of this article. In this study, first, with the help of the expert team and using the fuzzy screening approach, the critical effective criteria in the evaluation and prioritization of seismic retrofitting of infrastructures were identified. The most important indicators for evaluating seismicity intensity, distance from the fault, type of use (passenger and cargo), and the current state of infrastructure resistance were selected. Then, the expert team evaluated the current state of each infrastructure (station, bridges, tunnels, blocks) using fuzzy logic. In the following, according to the evaluation of the expert team and the screened indicators and using the TOPSIS fuzzy method, the most critical priorities for retrofitting were evaluated and identified. For this purpose, the geographical information on seismicity intensity and the location of faults in Razavi Khorasan Province was matched to the railway network of the Khorasan General Directorate of Railways. The results of this study show that the Torbat-Abumuslem and Abumuslem-Kashmar blocks with proximity coefficients of 0.25 and 0.28, respectively, have the highest priority for seismic retrofitting. The need for seismic retrofitting of all three tunnels in the Khorasan region with a proximity coefficient of 0.544 is assessed as medium. Among the bridges studied, Attar Bridge and Shahid-Motahari Bridge with proximity coefficients of 0.322 and 0.447, respectively, and among the stations studied, Neyshabur and Shahid-Motahari stations, both with a proximity coefficient of 0.322, require more attention in seismic retrofitting. The results obtained show that the railway axis from Motahari station to Mashhad and from Mashhad to Niqhab, especially the blocks between Fariman and Kashmar, Attar and Motahari bridges, and Neyshabur and Motahari stations, have a higher priority for seismic retrofitting. https://www.bese.ir/article_718474.html The main purpose of this research is to identify and analyze the vulnerability and weaknesses in a neighborhood and provide solutions to increase resilience against earthquakes. To achieve this purpose, survey and descriptive-analytical methods have been used. The applied methodology is field-based. The required data has been collected and analyzed by reviewing specialized texts and field survey with the presence, observations and visits of the neighborhood. The case study of this article is Shahid Beheshti neighborhood located in Chahardangeh, Tehran. First, the research identified the neighborhood from objective and subjective points of view, which includes uses (incompatible uses, service and relief uses, etc.), radius of access, enclosure, type and pattern, width and direction of roads, intersections, structure of the neighborhood and other required parameters. Then, the article identifies the strengths and weaknesses of the neighborhood and presents the suggested measures and solutions to reduce the vulnerability of Shahid Beheshti neighborhood against earthquakes. The elements that are effective in the vulnerability of the neighborhood mainly include physical dimensions, accessibility, infrastructure networks and social structure. The vulnerability of the urban fabric in Shahid Beheshti neighborhood, although it is caused by the low resistance and instability of the buildings, but the impenetrability of these fabrics is mainly due to the inappropriate access of the rider and the compactness of the fabric, which is caused by the fineness and the abundance of small parcells, which makes the high vulnerability of these fabrics, especially against earthquakes. Moreover, the improper placement of physical elements and incompatible uses, inefficient communication network, compact buildings, lack of infrastructure facilities, as well as improper distribution of urban open spaces also play a major role in increasing the vulnerability level to earthquakes. Therefore, positive steps can be taken in the field of reducing the vulnerability of urban areas by recognizing, making policies and presenting the right solutions. Furthermore, interaction between people and local institutions is significant in creating an integrated disaster risk management system. Based on the investigations conducted in Shahid Beheshti neighborhood, 8 strengths, 14 weaknesses, 8 opportunities and 11 threats were identified. After drawing the axis diagram of SWOT coordinates, growth strategy got 64 points, confrontation strategy 88 points, review strategy 112 points and defensive strategy 154 points. According to the points of each sector, the strategy derived to reduce the vulnerability level of the desired neighborhood is defensive strategy. In this article, based on the derived strategy, general programs were compiled and solutions and suggestions were presented. The presented solutions were classified in the fields of land use, physical, infrastructural, access and public space. Preparation of neighborhood identification maps, safe and vulnerable areas of the neighborhood, suitable places for emergency evacuation and planning for disaster risk management are among the findings and outputs of this study. https://www.bese.ir/article_720480.html One significant consequence of an earthquake is the generation of horizontal and vertical displacements on the Earth's surface. These displacements can lead to substantial human and financial losses, varying -according to the earthquake's intensity and location. Given Iran's position along the seismically active belt and the presence of the vast Alborz and Zagros mountain ranges, it is crucial to monitor the movements of numerous faults in regions adjacent to these mountains. Over the past two decades, remote sensing techniques utilizing satellite radar imagery have been vital for forecasting and assessing ground movements. In this article, we used InSAR technique and Sentinel-1 radar images to investigate the surface displacement caused by the Feb. 17, 2021 earthquake in Sisakht, Iran. Four images from the Sentinel-1A sensor, captured before and after the earthquake in both ascending and descending modes, were processed in the SNAP software. The results indicate that the maximum displacement in Sisakht is approximately 10 cm along the line of sight (LOS). Decomposing the LOS displacement revealed estimated values of -161 mm for the east-west component and 6 mm for the up-down component. Considering the extent of the Iran and its location on the main earthquake belt, as well as the presence of many faults with high seismicity in most regions of the country - especially in the areas adjacent to the Zagros and Alborz mountain- the use of classical mapping techniques, Due to time-consuming mapping methods and high labor costs, it is almost impossible to measure and monitor deformation. For this purpose, in recent years, remote sensing and radar imaging-based technologies have been widely used to monitor large areas in short periods of time. Among these technologies, the radar interferometry method is combined with the aperture radar, which is called the InSAR method for short. One of the most important effects of an earthquake is the creation of horizontal and vertical displacements on the earth's surface, as a result of which - according to the intensity and the region of the earthquake - many human and financial losses may occur. Considering Iran's location on the earthquake belt and the presence of two huge mountain ranges, Alborz and Zagros, monitoring the movements of many faults in the areas adjacent to these mountain ranges is very important. The use of remote sensing method based on the use of satellite radar images has played a very important role in predicting and measuring earth movements in the last two decades. In this article, in order to investigate the ground displacement caused by the 29th Bahman earthquake in Sisakht city, the technique of radar interferometry (InSAR) has been used. For this purpose, by using the four images obtained from the Sentinel-1A sensor before and after the earthquake in the ascending and descending states of the satellite orbit and processing these images in the SNAP software, the ground displacement map due to the occurrence of this earthquake was created. Earthquake prepared. The results showed that the maximum displacement in Sisakht city is about 10 centimeters along the line of sight of the satellite. By dividing the displacement obtained along the line of sight into two displacement components in the east-west (x component) and up-down (z component) displacement map was prepared in both x and z directions. These maps provide basic information required for earthquake engineering processes. https://www.bese.ir/article_720481.html Being located on the Alpine-Himalayan belt, Iran is located in one of the most earthquake-prone places in the world. As it is clear in the zoning of the seismic maps of Iran, a large part of the country is in the relatively high-risk zone. From the published reports about Iran's earthquakes, it can be seen that the most type of these earthquakes are shallow crustal, which have always been more destructive. In such a situation, it is necessary to evaluate the vulnerability and seismic performance of existing buildings according to their importance and type of structure. For this reason, the evaluation of the seismic performance of buildings such as school buildings, which are among the most important buildings due to population density, is of great interest. For this reason, in this study the seismic fragility curves of reinforced concrete school buildings in Isfahan province are determined to investigate their seismic vulnerability. Based on existing school in Isfahan province, the structural types of the school building were moment reinforced concrete frames, steel frames and masonry buildings. The statistical document in Renovation and Equipping schools of Esfahan organization shows that the most structure types were reinforced concrete structures. These buildings were designed based on different editions of standard 2800 in areas with different seismic risk and have different number of floors. The selected buildings of schools were divided into 14 general categories in terms of height, revision of design regulations, seismic risk and land type. In order to evaluate the vulnerability of selected buildings, incremental dynamic analysis (IDA) was performed using 22 far fault accelerograms as well as 12 near field accelerograms on two-dimensional frames in OpenSees software. The accelerograms were recorded on soil with site class D based on NEHRP. The nonlinear behavior of concrete and steel bars were modeled using concrete02 and steel02 models respectively, available in OpenSees. Moreover, the P-Delata effects were considered in the 2-D frame models by using leaning column available in the software. After calculating IDA curves, the seismic fragility curves were produced by considering the spectral acceleration in the main period of oscillation with 5% damping as the intensity measure and the maximum inter-floor drift as the failure index. It should be noted that log-normal distribution was using to determine fragility curves. The results showed that as the height of the structure increases, the fragility or vulnerability of the structures increases. Also, the probability of building collapse in areas with moderate seismic risk is higher than in areas with high relative risk. Moreover, according to the fragility curves It can be concluded that the one-story school buildings in high and moderate categories which had designed with third edition of Iranian seismic code (standard 2800) have lower priorities for strengthening. https://www.bese.ir/article_725152.html When seismic waves travel from the bedrock into the soil layers, resonance occurs. Generally, the concept of resonance means that the level of damage to surface structures increases. The closer the characteristics of the soil layers are to each other, the less resonance occurs; conversely, the more different these layers are from one another, the greater the resonance. Therefore, the presence of soft soil over bedrock causes the amplified acceleration to be transferred to the foundation of the structure, increasing the likelihood of damage to the structure. Topographic amplification refers to the phenomenon where seismic waves are enhanced or altered as they interact with the topography of a site, such as hills, valleys, and ridges. This amplification can significantly influence the seismic response of structures, leading to increased ground motion and potentially greater damage during an earthquake. Investigating topographic amplification and its effects on the seismic response of topographic sites is an important issue that has attracted considerable interest from many researchers. Studies in the area of topographical influences have shown that the nature of the terrain is instrumental in influencing the level of damage caused by earthquakes. Local topographical formations can enhance intense ground movements during earthquakes, resulting in significant damage. Iran is located in a seismically active region, with many areas in the country adjacent to various topographies, especially hills. Given the presence of active faults in the country and a history of significant earthquakes, it is essential that the design and construction of structures are carried out in a way that provides sufficient resistance to these influential factors. Studies and research conducted on the effects of topography and the phenomenon of seismic wave amplification as they pass through surface layers have shown that topography has a considerable impact on the extent of earthquake damage. In this research, the hill model in the form of a semi-sinusoidal shape is examined in two layers, as well as the effects of this type of site on the amplification of ground response. By modeling several semi-sine hills with different stratifications using FLAC software under Rayleigh wave conditions, the impact of topography is investigated. Before conducting the modeling, the accuracy of the analytical method must be verified. For this purpose, validation studies from Wang (1982) and results from other researchers will be used to authenticate the analysis of two problems. Finally, to ensure the accuracy of the FLAC software, a similar model will be constructed, and by applying a Rayleigh wave, the desired parameters will be determined at various points of the site (semi-sinusoidal hills) and compared with the graphs from the article. This research examines how a frequently found topographical feature, particularly semi-sinusoidal hills, influences the seismic reaction of the Earth's surface when exposed to vertically propagating SV waves. The main objective of this research is to examine the effects of various layering at a specific type of site, namely semi-sinuous hills. The study aims to model and analyze the seismic response of this type of site, investigating the impact of surface topography on seismic behavior and comparing the results obtained from the analysis under different conditions. In this research, efforts have been made to investigate the seismic behavior of sinuous hills under different layering conditions to determine the effects of soil characteristics in the layers, as well as the thickness and angle of the layers on the results obtained. This study investigated how layering affects the response of semi-sinusoidal hills by analyzing hills with two layers, each featuring different layering characteristics and thicknesses. The study also examines the impact of soil characteristics, layering thickness and angle and the position of the looser layer. Different features in layering have an impact on the overall trend of amplification on the top of hills and de-amplification near the toes of hills in response to the horizontal components of displacement, velocity, and acceleration. The study revealed that in two-layer hills, the effects of soil characteristics are greater compared to the thickness and angle of layering. Overall, the most significant change in the acceleration component was observed when the upper layer was loosened in two-layer hills. Conversely, the smallest change in all three components occurred when the upper layer was halved. https://www.bese.ir/article_727807.html Elevated water tanks are among the critical urban and rural infrastructure, primarily used for maintaining water pressure in distribution networks and storing water for residential and industrial areas. Despite various studies conducted on water tanks, limited research has focused on the seismic behavior of elevated tanks with braced steel frame systems. During the Ezgeleh earthquake in Kermanshah (November 12, 2017), several steel elevated water tanks in Sarpol-e Zahab city suffered damage. In this study, in addition to reviewing the damages to five existing elevated water tanks during the Kermanshah earthquake, the effects of soil–structure interaction (SSI) on the seismic behavior of these tanks are investigated. The water inside the tanks was modeled using the spring–mass system proposed by Housner [6] and Guideline No. 604 [1] (Seismic Design Guide for Water Supply Systems). To account for the influence of SSI on the behavior of these structures, the cone model method for shallow foundations (Monkey Tail Model) [8] and the approach proposed by the Iranian Seismic Code (Standard No. 2800) [3] were employed. The study further demonstrates that site conditions contribute to increased lateral displacements and fundamental periods of the tanks. Finally, the results obtained from the cone model [8] and the 2800 Code approach [3] are compared and discussed.مخازن هوایی آب ازجمله تاسیسات مهم و حیاتی شهری و روستایی به شمار می‌روند، که برای تامین فشارآب مورد نیاز در شبکه آبرسانی و هم‌چنین ذخیره سازی آب مصرفی درمناطق مسکونی وصنعتی کاربرد فراوانی دارند. در زلزله ازگله کرمانشاه ایران که در تاریخ 21 آبان ماه 1396 به وقوع پیوست، تعدادی از مخازن هوایی فولادی شهر سرپل ذهاب دچار آسیب دیدگی گردید که در بعضی موارد منجر به از دست رفتن آب ذخیره مخازن و یا عدم کارایی مخازن گردید. در این مقاله ارزیابی کیفی از 4 مخزن هوایی آب موجود در زلزله کرمانشاه صورت گرفته است و تاثیر اندرکنش خاک و سازه در رفتار این مخازن در اثر زلزله مورد بررسی قرار گرفته است. برای مدل سازی آب درون مخزن از مدل جرم وفنر ارائه شده توسط هاوزنر و نشریه شماره 604 ایران که مربوط به راهنمای طراحی لرزه ای سامانه آبرسانی می‌باشد، استفاده شده‌ است. و برای احتساب اندرکنش خاک وسازه نیز از روش مدل مخروطی برای پی‌های سطحی (مدل دم میمونی) و روش پیشنهادی آیین‌نامه 2800 ایران، طراحی ساختمان در برابر زلزله، استفاده شده است. با توجه به نتایج بررسی رفتار لرزه ای مخازن هوایی فلزی آسیب دیده در زلزله ازگله کرمانشاه مشخص گردید با افزایش میزان پرشدگی مخازن و افزایش جرم موثر لرزه ای آنها، زمان تناوب کل سازه نیز افزایش خواهد یافت. افزایش ارتفاع مخازن ساخته شده بر روی دکلهای نگه دارنده نیز سبب می شود زمان تناوب کل سازه این مخازن افزایش یابد. هم‌‌چنین بررسی رفتار تلاطمی مخازن مورد بررسی نشان داد در سازه مخازن هوایی با افزایش زمان تناوب مخزن، برش پایه استاتیکی مخازن و نیروی تلاطمی مخازن نیز افزایش می یابد. هم‌چنین به طورکلی بررسی تاثیر اندرکنش خاک و سازه در بررسی رفتار لرزه ای مخازن هوایی نشان از افزایش زمان تناوب این سازه ها بادرنظر گرفتن اندرکنش خاک زیر سازه را دارد. میانگین میزان افزایش زمان تناوب سازه مخازن هوایی با مدلسازی خاک ایستگاه 1تا 5 به ترتیب 2.59، 1.55، 1.76، 2.04و 1.83 درصد می‌باشد. هم‌چنین مقادیر تغییرمکان جانبی کف مخازن با در نظر گرفتن اندرکنش خاک و سازه در حالات تکیه‌گاه خاک ایستگاه‌های 1 تا 5 و با استفاده از دو روش مخروطی و روش پیشنهادی آیین نامه 2800 نسبت به حالت تکیه‌گاه گیردار افزایش می‌یابد. مطابق جدول 7 که مربوط به میزان افزایش تغییر مکان جانبی کف مخازن در ایستگاه های خاک 1تا 5 با در نظر گرفتن اندرکنش خاک و سازه می‌باشد، ملاحظه می‌شود که بحرانی ترین تکیه گاه خاک مورد مطالعه، خاک ایستگاه 1 می‌باشد. که میزان افزایش تغییر مکان حانبی کف مخازن نسبت به حالت تکیه‌گاه گیردار در اثر اندرکنش خاک و سازه به روش مخروطی و روش 2800 به ترتیب 11.4 درصد و 29.6 درصد می‌باشد. هم‌چنین ملاحضه می‌شود که طبق نتایج جدول 8 و جدول 9 که به ترتیب مربوط به کنترل گسیختگی خاک ناشی از کمبود ظرفیت باربری و کنترل لغزش افقی پی برای مخازن مورد مطالعه در تحلیل استاتیکی خطی می‌باشد، برآورد می‌شود که ابعاد و ضخامت پی در مخازن مورد مطالعه، در برابر گسیختگی ناشی از کمبود ظرفیت باربری و لغزش افقی پی، خاک زیرسازه ایمن می‌باشند. https://www.bese.ir/article_727808.html Masonry structures have always been used worldwide due to the simplicity of construction and low cost. In recent years, we have seen damages caused by earthquakes that resulted in severe damage to these structures; Therefore, it is important to investigate their behavior to identify and improve their performance against earthquakes. The purpose of this article is to evaluate the seismic behavior of 20 cm masonry walls with two types of straight and block brickwork in unreinforced and reinforced with CFRP sheets against earthquake force, both walls were reinforced by the cross method, as well as the straight wall by the combination of cross strips and The horizontal was also strengthened. For this purpose, by using simplified micro-modelling using the finite element method in Abaqus software and verifying it with laboratory samples, the desired walls were modelled under seismic load and their seismic parameters were investigated with the help of the hysteresis curve of the walls. In unreinforced walls, the parameters of plasticity coefficient, bearing capacity, and wasted energy in straight brickwork were more and its strength loss was less than in block brickwork. But in the case of cross-strengthening, the wall with block brickwork had more ductility, effective stiffness, load capacity, wasted energy and strength loss than the wall with straight brickwork. In general, the effect of reinforcement sheets on the seismic parameters of the straight wall was more than that of the block wall. Also, the cross-reinforcement method performed somewhat better than the combined method only in terms of ductility coefficient and strength loss.Masonry structures have always been used worldwide due to the simplicity of construction and low cost. In recent years, we have seen damages caused by earthquakes that resulted in severe damage to these structures; Therefore, it is important to investigate their behavior to identify and improve their performance against earthquakes. The purpose of this article is to evaluate the seismic behavior of 20 cm masonry walls with two types of straight and block brickwork in unreinforced and reinforced with CFRP sheets against earthquake force, both walls were reinforced by the cross method, as well as the straight wall by the combination of cross strips and The horizontal was also strengthened. For this purpose, by using simplified micro-modelling using the finite element method in Abaqus software and verifying it with laboratory samples, the desired walls were modelled under seismic load and their seismic parameters were investigated with the help of the hysteresis curve of the walls. In unreinforced walls, the parameters of plasticity coefficient, bearing capacity, and wasted energy in straight brickwork were more and its strength loss was less than in block brickwork. But in the case of cross-strengthening, the wall with block brickwork had more ductility, effective stiffness, load capacity, wasted energy and strength loss than the wall with straight brickwork. In general, the effect of reinforcement sheets on the seismic parameters of the straight wall was more than that of the block wall. Also, the cross-reinforcement method performed somewhat better than the combined method only in terms of ductility coefficient and strength loss. https://www.bese.ir/article_728295.html Lap splices for rebar connections are a traditional and cost-effective method but face challenges in seismic zones due to stress concentration and bond degradation under cyclic loads. Key limitations include reduced ductility, concrete splitting risks, and longer splice lengths (typically 40-60 bar diameters), which can congest reinforcement layouts. Modern alternatives like mechanical couplers (e.g., threaded or grouted sleeves) offer superior performance in high-stress regions by ensuring force transfer without relying on concrete bond. Mechanical splicing of reinforcing bars is a modern technique used to connect two rebars without relying on conventional lap splices or welding. This method ensures structural continuity while improving load transfer efficiency and reducing congestion in reinforced concrete structures, especially in regions with dense reinforcement. This innovative method not only ensures the structural integrity of the assembly but also improves load-transfer efficiency between connected bars. Additionally, it alleviates rebar congestion-a common issue in reinforced concrete structures, particularly where multiple bars intersect. Mechanical splicing, commonly referred to as rebar couplers, involves various connection methods, including threaded couplers, swaged couplers, and sleeve couplers. These components are precision-engineered to ensure a secure and direct rebar connection. The benefits of using mechanical splices are numerous. They not only deliver greater strength and reliability but also improve connection durability—all while meeting the strict demands of current building codes and industry standards. The use of rebar in concrete structures is essential, as it effectively compensates for concrete’s inherent limitations-particularly its well-known weakness in tensile strength, which is far lower than its compressive strength. However, it is important to note that when a structural element's length significantly exceeds the standard 12-meter rebar length commonly available in commercial markets, splicing becomes an unavoidable necessity in both design and construction. One of the most commonly used methods for splicing rebars is the lap splice method. This involves overlapping a specific length of rebar and securing it together with rebar wire. It is crucial to follow established regulatory standards when performing this essential construction practice. In recent times, the use of mechanical splices has garnered considerable attention and interest from designers and builders. These splices offer a practical solution for enhancing construction quality and reducing project costs, making them a compelling alternative to traditional methods. The evaluation of these mechanical splices is conducted in compliance with stringent standards, including ISO 15835 and ASTM A1034, which provide comprehensive guidelines for their use in construction projects. This article begins with a comparative analysis of international standards and Iran’s Code 9 (Design and Construction Provisions for Structural Reinforced Concrete Buildings), focusing on mechanical splices. The study highlights key similarities and differences between these two standards in particular. It then evaluates various experimental studies in this field and compares their findings with the limits and criteria set by international standards, offering a comprehensive overview of the current state of knowledge. https://www.bese.ir/article_728510.html The steel shear wall has been introduced as a system with high stiffness and strength and a considerable capability to absorb seismic energy. Due to its special advantages compared to other lateral load-resistant systems, this system is being used in tall buildings more and more frequently. Using corrugated sheets together with flat sheets increases the sheet's elastic resistance and the ductility of the lateral bearing system. Therefore, in this article, it is suggested that a combination of corrugated and flat sheets be used for the steel wall. This research investigates the stiffness of a shear wall consisting of corrugated and flat plates. The shear wall plates consist of two trapezoidal corrugated plates and two flat plates connected with high-strength bolts. This proposed shear wall can be replaced in tall buildings as an alternative to the normal corrugated plate shear wall to resist lateral shear loads caused by seismic or wind effects. In this research, stiffness constants, including bending stiffness constants in orthotropic directions and torsional stiffness constants, have been theoretically derived using elastic theory. Then, by comparing the relationships of stiffness constants and using its results for the frame-wall interaction theory, the accuracy of these extracted relationships for use in modeling purposes and estimating seismic parameters without the need for finite element modeling is confirmed with sufficient accuracyThe steel shear wall has been introduced as a system with high stiffness and strength and a considerable capability to absorb seismic energy. Due to its special advantages compared to other lateral load-resistant systems, this system is being used in tall buildings more and more frequently. Using corrugated sheets together with flat sheets increases the sheet's elastic resistance and the ductility of the lateral bearing system. Therefore, in this article, it is suggested that a combination of corrugated and flat sheets be used for the steel wall. This research investigates the stiffness of a shear wall consisting of corrugated and flat plates. The shear wall plates consist of two trapezoidal corrugated plates and two flat plates connected with high-strength bolts. This proposed shear wall can be replaced in tall buildings as an alternative to the normal corrugated plate shear wall to resist lateral shear loads caused by seismic or wind effects. In this research, stiffness constants, including bending stiffness constants in orthotropic directions and torsional stiffness constants, have been theoretically derived using elastic theory. Then, by comparing the relationships of stiffness constants and using its results for the frame-wall interaction theory, the accuracy of these extracted relationships for use in modeling purposes and estimating seismic parameters without the need for finite element modeling is confirmed with sufficient accuracyThis proposed shear wall can be replaced in tall buildings as an alternative to the normal corrugated plate shear wall to resist lateral shear loads caused by seismic or wind effects. In this research, stiffness constants, including bending stiffness constants in orthotropic directions and torsional stiffness constants, have been theoretically derived using elastic theory. Then, by comparing the relationships of stiffness constants and using its results for the frame-wall interaction theory, the accuracy of these extracted relationships for use in modeling purposes and estimating seismic parameters without the need for finite element modeling is confirmed with sufficient accuracy https://www.bese.ir/article_728657.html Seismic Hazard Analysis, although aiming to provide a fair estimate of the ground acceleration at a given site, sometimes underestimates the actual recorded values in certain regions. For example, the earthquake of August 8, 2010 (30 July 2010) in the city of Torbat Heydarieh, with a moment magnitude of 5.9, recorded a peak ground acceleration (PGA) of 425 cm/s² at a local station a value significantly higher than the predictions from global, regional, or even local attenuation models and seismic codes for that area. This considerable discrepancy highlights the significant role of local mechanisms in amplifying ground motion. The objective of this study is to investigate various factors contributing to this high acceleration, including site soil amplification, rupture directivity, and basin response effects. To this end, the study employed component analysis of accelerograms, continuous wavelet transform, pulse indicator methods, angular analysis of acceleration components, and spatial distribution of recorded acceleration. Additionally, the effect of directivity was modeled for two rupture initiation scenarios. Findings revealed that site soil amplification alone could not explain the observed high acceleration. The analysis of rupture directivity indicated that the dominant acceleration component at near-fault stations like Torbat Heydarieh, Jangal, and Shadmehr was mainly perpendicular to the fault strike, with noticeable energy concentration in the early part of the record. Although Baker’s pulse indicator classified the earthquake as non-pulse-like, the pulse-to-total energy ratio (0.446) according to the Zhai criterion indicated a possible occurrence of directional pulse. However, with a more precise modeling of directivity using the Bils model (2024) and accounting for potential errors in source motion, it was observed that directivity alone could not definitively explain the high ground acceleration. Ultimately, the investigation of basin effects showed that sedimentary basin amplification could justify the strong motion observed in the city center of Torbat Heydarieh. The geological analysis of the Torbat Heydariyeh region, along with comparison to the ground acceleration distribution map, indicates that peak ground accelerations are primarily located in areas with soft, alluvial, and low-strength soils. This spatial correlation confirms the effect of local site amplification, emphasizing the necessity of incorporating it into seismic hazard assessments and structural design. More complex phenomena—such as basin edge effects and overall basin effects—especially in areas with heterogeneous geological arrangements, can significantly influence ground motion, either amplifying or attenuating it. Overall, it can be concluded that the Torbat Heydariyeh earthquake was simultaneously influenced by three key factors: Rupture directivity, Site amplification and Amplification caused by sedimentary basin effects. The overlap of these phenomena, particularly in areas close to the fault, underscores the critical importance of accounting for local site effects in seismic hazard evaluations and earthquake-resistant design. Hence, to perform a precise analysis of site effects, it is essential to simultaneously and integrally examine various factors such as rupture directivity, dynamic soil properties, and the geometry and seismic response of the sedimentary basin. https://www.bese.ir/article_731470.html Earthquake forecasting remains one of the most pressing challenges in the geosciences. Space-based sensing has emerged as an innovative technique for detecting potential earthquake precursors, particularly through observation of ionospheric and stratospheric anomalies. The primary objective of this research is to systematically investigate and assess the effectiveness of different satellite payloads for earthquake precursor detection, with a specific focus on identifying and recommending a suitable payload for deployment on a domestic Iranian satellite platform. A comprehensive literature review highlights several classes of space-based precursor signals, including changes in the electrical and magnetic fields detected in the ULF, ELF, and VLF frequency bands, ionospheric total electron content (TEC) fluctuations, and stratospheric temperature anomalies. To critically evaluate the practicality and performance of these payloads, data from international missions such as CSES-1, DEMETER, and TIMED were analyzed alongside studies of recent major earthquakes in Iran and worldwide. Among the investigated methods, ULF-band electric field detectors show promising results in detecting electromagnetic anomalies up to several days before significant seismic events, especially for earthquakes with magnitudes above 5.8. However, their practical application on smaller satellites is constrained by the need for long deployable booms and stable attitude systems—features not present in the selected domestic platform, which utilizes gravity-gradient stabilization. Similarly, search coil magnetometers offer valuable high-resolution electromagnetic measurements, but their optimal performance requires non-conductive structures for boom mounting, which are not compatible with the current satellite’s conductive (copper-beryllium) stabilization boom. Alternatively, ionospheric tomography using a tri-band radio beacon is identified as the most viable and effective technique for the domestic satellite. This payload can transmit three simultaneous, phase-coherent signals (VHF, UHF, L-band) toward the ground, where an array of ground stations receive the signals and, through tomographic processing of phase and amplitude variations, reconstruct three-dimensional maps of ionospheric electron density. The technical simplicity and low mass/power requirements of the tri-band beacon make it fully compatible with the constraints of the domestic satellite platform. Furthermore, the satellite’s existing communication subsystems can be leveraged, enabling cost-effective integration and operation. Complementary approaches, such as satellite radiometers for stratospheric temperature monitoring and ground-to-satellite VLF signal analysis, add further diagnostic power but are limited in this context due to size, mass, or technical incompatibilities. Nonetheless, the inclusion of store-and-forward data relay capabilities provides a major advantage for collecting seismological data from remote ground-based stations, improving the timeliness and coverage of earthquake early warning systems. In conclusion, after detailed evaluation against mission, technical, and operational requirements, the tri-band beacon payload is recommended as the optimal solution for the domestic satellite. This instrument provides a robust, and scientifically validated means for space-based monitoring of earthquake-related ionospheric anomalies over Iran. The implementation of a dedicated ground receiver network will further enhance the system's effectiveness and advance Iran's capabilities in earthquake precursor research and early warning. https://www.bese.ir/article_731471.html Gas pipelines are considered as lifelines, protection of which is essential for safety, uninterrupted service to the industry and society and preservation of the environment. In Iran, due to the existence of thousands of kilometers of oil and gas pipelines and the extent of active faults, intersection of pipelines with faults is inevitable. Therefore, it is necessary to analyze the hazard of fault rupture for pipelines and take essential design considerations. Through the fault rupture hazard analysis, the permanent deformation of the ground is estimated. Conventionaly, the expected displacement is determined for a certain level of earthquake. This is the so called deterministic approach. Nevertheless, due to the great uncertainties in earthquake parameters (such as uncertainties in magnitude, distance and return period), there is another approach that relates the earthquake-induced force/displacement to its probability of occurrence. This provides insight for the designers to take mindful decisions on the risk level considering the importance of their structure. In this paper, the recent approach, called Probabilistic Fault Displacement Hazard Analysis (PFDHA) is considered for strike-slip faulting and applied to the North Tabriz Fault. The North Tabriz Fault is a major seismogenic fault traversing northwestern Iran with strike slip mechanism. This fault has been responsible for many devastating earthquakes and surface fault ruptures. Many historical earthquakes have occurred in the Tabriz region (e.g., the 858, 1042, 1273, 1304, 1550, 1641, 1717, 1721, 1780 and 1786 earthquakes). Among these arthquakes, the destructive earthquakes of 1042 (Ms 7.3), 1721 (Ms 7.3) and 1780 (Ms 7.4) were accompanied by surface faulting. The surface rupture in 1721 and 1789 earthquakes extended for at least 50 and 60 kilometers, respectively. Therefore, probabilistic fault displacement hazard analysis has been performed for different locations on the North Tabriz Fault, including the intersection of this fault with Tabriz-Ankara gas pipeline which is of special concern. Herein, earthquake data is gathered for Tabriz region from International Seismological Center (ISC) over a period of 50 years from 1970 to 2020 and organized to derive the recurrence law. Considering the mainly strike-slip mechanism of this fault, fault displacement attenuation functions and magnitude-rupture length relations for strike-slip faults have been used. The present study exclusively focuses on principal fault displacement and does not address distributed displacements. The analysis results are presented in the form of mean annual rate of exceedance for different fault displacements and the principal fault displacement in the return periods of 475 and 2475 years have been compared. Several site locations, including the intersection of fault and gas pipeline, are considered in this study. The results show that 131 cm and 432 cm of fault displacement is anticipated in the intersection of fault and gas pipeline in the return periods of 475 and 2475 years, respectively. Moreover, fault rupture hazard map of the North Tabriz Fault is illustrated for the return period of 475 years. According to this hazard map, higher fault displacement is expected in the middle part of the fault. https://www.bese.ir/article_731717.html Although seismic isolation is not a new technology, and it is now several decades that it is used in buildings located in earthquake prone areas of the world, the usage of this technique has not been acknowledged so much in many developing countries due to its high manufacturing and maintenance costs. Fortunately, among various seismic isolation systems, those which are based on rolling motion are much cheaper, and their employment can be encouraged easier in developing and even developed countries. As such, in this paper, a new seismic isolation system based on combination of rolling and pendulum behaviors, is proposed. This system consists of a pairs of rolling rods, each having a geometric shape of a cradle, where the point of inertia loads application is significantly distant from the rolling support. This distance causes the rolling motion to blend with pendulum motion. To evaluate the proposed system’s performance in the seismic response reduction of structures, the equations of motion were first derived for an isolated rigid body, considering the pendulum rotation angle as the independent variable in the proposed isolating system. Since the system's behavior is geometrically nonlinear, using the Lagrange equation, potential and kinetic energies of the system were derived, along with the variations of non-conservative works, to extract the differential equation for the isolated rigid body. In the second step, the differential equation which governs the motion of a single-degree-of-freedom structure located on the proposed isolation system, were developed. By numerical solution of the governing equations of motion by the modified forth order Runge-Kutta-Nistrom method through coding in MATLAB platform, the system's responses under the simultaneous effects of horizontal and vertical components of a series of selected seismic records were obtained in both isolated and non-isolated conditions, and the results were compared. The structures examined in this study include a concentrated mass system on the isolator as well as a single-story frame on the isolator, which both were subjected to three groups of high, medium, and low-frequency seismic records. Furthermore, to make sure that geometric form and size of all parts of the proposed cradle-form rolling pendulum isolator are appropriate from strength point of view, so that no yielding does not happen in them, as well as no excessive deformation, an extensive finite element analysis was also conducted. The results of seismic response analyses showed that using this isolation system can lead to significant reduction in the absolute acceleration, base shear, and story drift of the structure of around of 70% on average for almost all of the applied high, medium, and low-frequency records, although for some record this reduction is not much satisfactory. Additionally, the displacement at the isolation level averaged 40 cm. By increasing the pendulum length from 2 to 2.5 or 3 meters, the absolute acceleration of the isolated system was further reduced. https://www.bese.ir/article_735076.html This paper investigates the seismic behavior of rectangular alluvial valleys subjected to SV and SH waves. A two-dimensional dynamic analysis is performed using the linear finite element method to evaluate the response of these valleys. The primary objective of this study is to assess the influence of geometric and mechanical parameters on the seismic response of the valleys and to evaluate the response ratio under SV and SH waves. Additionally, the effect of the valley shape ratio on amplification and natural period is examined, identifying the maximum amplification points on the valley surface. The results indicate that the amplification pattern is significantly affected by the valley shape ratio. As the shape ratio decreases, the natural period increases and the maximum amplification typically occurs at the valley center. The findings also reveal that the dynamic response of valleys depends on the type of incident wave. SH waves tend to cause higher amplifications at lower frequencies and are more sensitive to geometric variations, while SV waves exhibit more complex behavior near the valley’s natural frequency. The analyses highlight the existence of a uniform characteristic period for surface points on the valleys, which can assist in the preliminary estimation of the natural period of alluvial valleys. 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