https://www.jsee.ir/ Journal of Seismology and Earthquake Engineering en daily 1 Wed, 01 Jan 2025 00:00:00 +0330 Wed, 01 Jan 2025 00:00:00 +0330 https://www.jsee.ir/article_716388.html Using the finite element method, this study investigates the seismic behavior of hunchbacked block-type gravity quay walls with varying configurations. The research employs adaptive meshing strategies and error-based adaptivity techniques to refine the plane strain FE meshes. Interface elements are utilized to simulate discontinuities along the wall height, particularly between concrete blocks, and to model the interaction between the quay wall and the adjacent soil medium. The developed FE models are validated against data from 1g shaking table tests available in the literature. The study evaluates the seismic performance of three quay wall models, each with a unique configuration, under a range of seismic loads, including peak ground accelerations from 0.1g to 0.9g and frequencies from 3.0 Hz to 9.0 Hz. The findings indicate that increasing hunch height and optimizing the upper inclination angle effectively reduce lateral earth pressures and horizontaldisplacements, enhancing seismic performance. The study recommends positioning critical structures, infrastructure, and sensitive buildings in the backfill area at a distance greater than the wall height, as maximum backfill settlement occurs between 0.55H and 0.65H from the quay wall, where significant settlement poses risks to facilities. Additionally, acceleration amplification in the backfill decreases at distances greater than the wall height, indicating reduced seismic impact. https://www.jsee.ir/article_715217.html The ability to compress time and enhance process quality are key determinants of effective New Product Development (NPD) and equallyDisaster Risk Reduction (DRR) management. This paper explores the qualitative relevence of an Analytical Hierarchy Process (AHP) derivedunified conceptual model of correlation coefficients between NPD subfactors of success and performance measures drawn from dominantclassical NPD models. The paper shows the application of the conceptual model to compare base isolation with damper technologies that are amongst the most advanced earthquake risk reduction strategies. The study finds that there are significant benefits for successful knowledge transfer between NPD and civil engineering and earthquake resilience engineering sectors, and there are many potential academic and professional benefits from doing so. https://www.jsee.ir/article_715115.html The Equivariant adaptive separation by independence (EASI) algorithm, as an online blind structural identification method, is very important not only to better understand the structural response but also to conduct an efficient maintenance and management strategy. However, the traditional EASI algorithm has some drawbacks. It uses a constant step-size parameter and requires establishing a trade-off between the misadjustment in the steady-state and the convergence rate. This paper proposes a new variable step-size equivariant adaptive source separation via independence (VS-EASI) algorithm for online blind modal identification of structures. Unlike the traditional EASI algorithm,the proposed algorithm adaptively updates its step-size based on the input signals and the unmixing matrix, through establishing a new function between the step-size and the separating indicator. This results in a better performance for the proposed method, and fast convergence speed is achieved while the steady-state error is low. Furthermore, this algorithm mitigates the irrelevant noise, making it more suitable than the EASI algorithm for practical applications. Simulation results of synthetic examples and a benchmark structure verify the superior convergence and better performance of the proposed algorithm in the steady-state over the conventional EASI with a fixedstep-size in stationary environments as well as non-stationary ones. https://www.jsee.ir/article_715218.html Eccentric bracing frames (EBFs) are one of the most suitable seismic resistance systems due to their high strength, ductility, and energy dissipation. In some EBF configurations, due to loading patterns or structural geometry, the link member can be subjected to a high axial load. The presence of high compressive axial loads increases the occurrence of buckling and thus reduces both its strength and ductility. Most of the studies conducted have focused on short links, and as mentioned in the commentary of the AISC seismic regulations, the effect of axial load on the behavior of intermediate and long links has not been sufficiently investigated, which highlights the need for further study. In this research, numerical modeling is first validated by experimental results. Subsequently, the overstrength factor of intermediate links made from European I-shaped sections subjected to axial loads is examined. The results indicate that the overstrength factor of intermediate links is lower than the prescribed value of 1.5 in the provisions. https://www.jsee.ir/article_715216.html One of the important advantages of steel plate shear walls (SPSWs) is the possibility of creating openings with various geometric dimensions and in different positions on the steel plate. The goal is to offer a novel kind of steel shear walls with an eccentric brace and enhance the system's seismic behavior by including a brace at the opening edges. To evaluate the performance of the proposed frames, a finite element analysis was used, considering the nonlinear parameters of materials and geometry under cyclic loading. The findings of the numerical models reveal that transforming the infill plate's surface into regular and smaller geometric forms causes the plate's buckling mode. Moreover, the extension of the braces and their connection to the bottom of the beam creates diagonal tension fields in the plate and prevents local buckling of the plate at the opening edge. https://www.jsee.ir/article_715254.html Rare earthquakes cause heavy damages to building structures. Design of structures using yield mechanisms that provide extra resources to ensure structural stability for intensity higher than the design-based earthquake (DBE), can be considered as a reasonable technique to reduce the collapse probability. In this regard, the design of a mass-isolated structural system with a multi-phase seismic behavior as a reliable lateral load-bearing system has been investigated. In this type of configuration, by separating the mass from the stiffness of the system in the vertical direction, the structural system is transformed into two subsystems (soft and stiff), which can be utilized as aneffective damping amplification technique by using an appropriate energy dissipation mechanism between these two parts. Furthermore, it can be used as an efficient seismic rehabilitation method for non-code-confirmed structures. In this study, in addition to performing parametric studies to determine the optimal damping coefficient, the impact and ultimate collapse mechanism of the system have been simulated and investigated numerically. The results of nonlinear time history analysis indicate that the mass-isolation technique can efficaciously improve the seismic performance of buildings compared to conventional structural systems due to the multi-phase seismicbehavior. https://www.jsee.ir/article_716066.html This paper investigates two important engineering demand parameters for assessing seismic performance of steel moment resisting frames equipped with linear fluid viscous dampers designed using the modified direct displacement-based design (DDBD) method. These parameters include the inter-story drift ratio (IDR) and the residual inter-story drift ratio (RIDR). For this aim, nonlinear dynamic time history analyses are performed at two seismic hazard levels, involving the design basis earthquake (DBE) and the maximum considered earthquake (MCE). The effects of panel zone flexibility and gravity framing are modeled in the analyses. In addition, the effect of considering and neglecting composite action on gravity framing and beam elements in moment resisting frames is investigated. The results show that inboth cases, the structures designed using the modified DDBD method could acceptably meet the performance target IDR limit. Additionally, it is shown that accounting for the effect of composite action leads to a reduction of about 4% in the maximum value of mean IDRs at both the DBE and MCE hazard levels. However, an increase of up to 12% is obtained for the maximum value of median RIDRs at the MCE level when the composite action is considered. https://www.jsee.ir/article_715116.html The underappreciated significance of perpendicular-to-facing relative settlements of geosynthetic reinforced soil (GRS) walls in seismic analyses is evident in the current literature, particularly when compared to along-facing settlements. Consequently, this study conducted a series of seismic finite element analyses to evaluate the perpendicular-to-facing settlements of a 20 m GRS wall during 36 significant worldwide earthquakes. Static and dynamic verifications of numerical modeling were performed by comparing the results of a 3.6 m physical GRS wall model and a 1 m shaking table test at the Royal Military College (RMC) of Canada, respectively. The reinforced soil modeling utilized the hardening soil constitutive model with small strain stiffness (HS-small). Additionally, the facing of the GRS wall model comprised 0.5 m × 1.5 m concrete panels. The findings emphasized the critical nature of relative deformations between the facing and reinforced zones, and between the reinforced and retained zones, in addition to absolute settlements. Moreover, the amount of relative settlements was found to be correlated with the intensity of seismic excitations. The correlations between relative settlements and intensity of earthquakes were also proposed based on the results of the current research. https://www.jsee.ir/article_715379.html Steel ring dampers are a type of yielding dampers that have a good energy dissipation capability. In this research, parametric studies were conducted to investigate the influence of the radius and thickness of the steel ring damper (SRD) on the seismic behavior of the RC frame. The numerical model was first calibrated with two experimental samples, then the impact of the damper on the concrete frame was investigated by performing pushover analysis. Simplified two-line curves were then obtained to calculate the seismic parameters of the frame, including stiffness, strength, ductility, and energy dissipation parameters. To estimate the elastic stiffness and ultimate strength of the concrete frame equipped with SRD, approximate equations were presented that were in good agreement with the numerical results. Finally, the most influential variables on the results were also identified. The results showed that reducing the radius of the damper and increasing its thickness increases the stiffness and strength of the frame. Also, increasing the thickness of the damper increases the energy dissipation and reduces the ductility of the frame. It was also observed that if the stiffness ratio of the damper to the bare frame is set to 4.1, the energy dissipation and ductility of the RC frame will be 2 times that of the bare frame. https://www.jsee.ir/article_716067.html This study takes the indoor substation adjacent to the elevated urban train line as the engineering background, investigates the structural vibration response law of the substation induced by the operation of the subway line through on-site vibration measurement, and proposes a novel nonlinear gas-spring quasi-zero stiffness isolator (NGS-QZSI) is proposed to reduce the structural vertical vibration and further reduce the safety distance. The software ABAQUS is used to establish a structure-equipment coupling numerical analysis model considering soil-structure interaction, and its effectiveness and accuracy are validated based on the measured results. The structural vibration response analysis is carried out under different vibration source distances, and a nonlinear gas-spring quasi-zero stiffness isolator is proposed to be employed for substation structural vibration isolation. The research results show that the substation structure under subway load excitation is dominated by vertical vibration, and its vibration response increases gradually with the increase of floor level. When the substation structure is less than 45 m from the subway line, the structural response exceeds the safety limit (12.5 μm/s) of the VC-C standard. With the vibration isolator attached, the structural vibration response is significantly reduced, with the peak and root mean square response controlled by more than 70%. Particularly, the safe distance of the substation from the subway line is reduced from 45 m to 20 m. Moreover, the frequency domain result analysis indicates that the proposed nonlinear vibration isolator can effectively control the low-frequency vibration of the structure. https://www.jsee.ir/article_717345.html In cases of large deformations of the ground underlying a structure, mat and grid foundations are two options to reduce probable differential settlements, due to their rigidity in the perpendicular directions and their relatively larger area compared with single spread foundations. A case study of large settlements of an 8-storey structure resting on soft saturated fine-grained soil due to seismic loading is numerically investigated herein. It is shown that performance of grid foundation is better or identical to mat foundations, which makes it an alternative with probably a more economical option to be preferred to mats in the design of foundations in areas of high seismicity. https://www.jsee.ir/article_717617.html Abstract- Recently, a number of much needed innovations have captured the attention of the earthquake engineering communities worldwide; the stiff braced rocking core, as part of conventional steel earthquake resisting systems (ERS), the introduction of low damage systems and components, the use of triple and mixed multiple seismic structures, and the sustainable seismic design (SSD) philosophy with a view to economy and environmental protection. SSD has the most challenging issue confronting structural engineers for decades. Regardless of carbon footprint reductions, unless a structure is designed for seismic sustainability it would be disposable with greater human diomfort, economic loss and harm to the environment. In the present context design implies planning for controlled seismic resistance, environmental protection, construction economy and Post-earthquake Realignment and Repairs, (PERR). In SSD the practicality of PERR is as important as the relevance of the theoretical assumptions, therefore, the non-lateral resisting items are carefully designed not to partake in seismic resistance. All Earthquake resisting structures (ERS) are designed for practical, residue-free recentering while their energy dissipating components are detailed to remain repairable/replaceable after the event. In the interim new categories of ERS, and innovative ideas have also been introduced. The authors hope this, and related articles will form the basis of SSD guidelines for earthquake prone resilient cities. https://www.jsee.ir/article_717750.html The amplification of ground motion at the surface is significantly influenced by soil properties, and constructing a reliable shear wave velocity model down to the seismic bedrock depth is indeed the key factor in determining a reliable seismic response. In Tehran, the previous site’s seismic response analysis relied solely on very shallow geotechnical measurements up to the engineering bedrock. The results showed the negligible amplification in frequencies higher than 1Hz, what was very different with the results of experimental amplification ratios, obtained using the site to reference method on real earthquake data (Haghshenas, 2005). The latter indicated a high level of amplification for a broad range of frequencies. In present study, we recalculated simple one-dimensional seismic responses for Tehran, using the newly developed deep shear wave velocity models, developed by Soltani et al. (2024; submitted), to evaluate whether these models accurately represents the actual site amplification. The results indicate that the relative differences between newly 1D calculated transfer functions and experimental observation are less than 20%. However, in certain stations, mostly in the central part of the basin, these differences exceeded 20%, which can be attributed to the inherent multi-dimensional behavior of the Tehran basin. https://www.jsee.ir/article_718610.html Reconnaissance, definition, mapping, and mechanism(s) of the earthquake sources are the preliminary earthquake hazard analysis strategies. Heterogeneity of the crust, change in stress, and diffuse and distributed nature of the present-day continental deformation are the features that may influence the seismic sources which, in turn, determine the seismic hazard assessment policy. The mechanisms and geometry of the sources potentially relate to the physics of the crust and then the magnitude, duration, and depth of generated earthquakes, etc. Tectonics, on the other hand, deals with recovering the stress state, and consequent deformations represented by geostructures, including the faults and folds. Therefore, the tectonic investigations and modeling may lead to better definitions and characteristics of the seismic sources. This study introduces a new approach to defining earthquake sources and segmentation, providing a practical guideline for evaluating earthquake occurrences. This evaluation model is supported by geological evidence that forms a crucial component of Probabilistic Seismic Hazard Assessment (PSHA) and Deterministic Seismic Hazard Analysis (DSHA) programs. The tectonic model's key output is the segmentation of fault zones responsible for earthquakes, some of which could be blind faults or faults yet to be identified as active faults. These regions might be regarded as aseismic areas in conventional seismic evaluations. The study recommends distinguishing between seismic hazard and seismic risk maps in regions where the potential for seismic activity is the same, but the population densities differ. https://www.jsee.ir/article_719253.html Field observations and studies of real earthquakes have highlighted the impact of underground subway tunnels on ground behavior during seismic events. In addition to these observations, both analytical and numerical studies have further validated this phenomenon. However, the limitations of existing analytical and numerical methods underscore the increasing need for field-based approaches, especially given the complex geometries of underground environments and the heterogeneous, anisotropic nature of subsurface profiles. With this goal, a comprehensive field (based on ambient noise measurements) and numerical study using a finite element method was carried out to investigate the effect of twin tunnels on the site seismic response, using Shiraz's under-construction subway tunnels. This article compares the site seismic response before and after the excavation of a single tunnel, while the effects of two adjacent tunnels will be addressed in a separate paper. The horizontal-to-vertical spectral ratio (H/V) results from field measurements at all stations reveal a distinct frequency peak below 1 Hz before tunnel excavation, which aligns with the geological conditions indicating the presence of thick alluvial deposits in the study area. The excavation of the tunnel has led to the elimination of the frequency peak directly above it. Additionally, subsequent numerical analyses show that subway tunnels contribute to the de-amplification of the ground seismic response above them, particularly for low-period input waves. https://www.jsee.ir/article_720482.html During the recent decades, the rapid growth of urban settlements has increased the risk of disasters. Therefore, improving the resilience of urban areas to natural hazards is essential. This article aims to evaluate earthquake resilience at local level by assessing and analyzing physical and social criteria. It proposes practical interventions at the micro, meso, and macro levels. A hybrid and field-based approach was applied for assessing the resilience of neighborhood against earthquakes as following steps: (1) To identify key components and indexes of physical and social resilience; (2) To determine tree structure for neighborhood resilience factors; (3) Field survey and data collection; (4) AHP analysis to determine the weights; (5) Performing GIS analysis to assess the earthquake resilience of the neighborhood. The proposed approach was applied in Jalaliyeh Neighborhood, Tehran, Iran, as a case study. The results reveal a spatial variation in the neighborhood’s earthquake resilience, with lower levels of resilience in the western parts compared to the eastern parts. The neighborhood’s average social resilience level is thirty percent and ‘low’, whereas its physical resilience level is ‘moderate’ with amount of fifty-one percent. The neighborhood’s resilience is distributed as follows: thirty-four percent very high, ten percent high, sixteen percent moderate, twenty-four percent low, and sixteen percent very low. The quantitative-qualitative approach, indicators, and criteria are applicable to assess the earthquake resilience of various urban neighborhoods, especially in similar contexts. Disaster risk managers can utilize this approach as a decision-support tool for improving the resilience and allocating the necessary funds accordingly. https://www.jsee.ir/article_721757.html Earthquake is one of the natural phenomena that threatens human life in areas around faults. Mathematical transformations are tools that can provide useful information to researchers in generating synthetic accelerograms, analyzing signals and accelerograms. With the help of mathematical transformations, recorded accelerograms of earthquakes can be considered as input signals and analyzed. Using Fourier transform, the frequencies present in the signal can be obtained, but it does not provide the temporal (or spatial) information of the signal’s constituent frequencies. The wavelet transform is a tool suitable for analyzing non-stationary waves and compensates for this weakness by providing not only the frequencies present in the signal but also the time (or location) of the frequencies. By changing the scale and translation parameters in the wavelet transform, the constituent frequencies of the earthquake wave and their occurrence time can be obtained. In this research, frequency analysis using wavelet transform was performed on the accelerograms of the 2020 Masha earthquake in near, intermediate, and far fields. Based on this analysis, the dominant frequencies of each wave and their occurrence moments were obtained, showing that in the near field, the dominant frequency of the earthquake wave is larger compared to the distant field. In other words, as the distance from the fault increases, the dominant frequency of the earthquake wave decreases, which is dangerous for tall structures with high natural period due to the resonance phenomenon. The results indicate the high capability of the continuous wavelet transform method in calculating the constituent frequencies of earthquake waves and their occurrence times. With this analysis, structures whose period matches the dominant period of the earthquake wave can be identified, and the effects of waves on structures can be examined more accurately. https://www.jsee.ir/article_722479.html The Drilled Flange connection is a reduced cross section beam connection that has been suggested by creating holes in the beam flange instead of the flange cut. In these connections, for quantifying the damage of a component, damage index can be used as a factor for parametric comparison of results from software modeling. This index includes pressure index, von Mises index, Equivalent Plastic Strain, triaxial strain and rupture. In this article the Mises and Equivalent Plastic Strain damage indices have been used in order to quantify the seismic behavior of DF connection. To better explain the concept of these indices, it can be said whenever the von-Mises stress is higher than the yield stress, failure will occur and the equivalent plastic strain will be greater than zero in the area that has been plasticized. According to the concepts, in the twenty four DF connection that has been modeled in ABAQUS software based on proposed patterns and parameters in FEMA, numerical analysis of damage to these connections with considering the effect of hole distance from the edge of the beam flange was investigated and the optimize model for transferring the maximum stress and plastic strain from the edge of the column has been determined https://www.jsee.ir/article_722777.html Ahvaz City, situated on the southern side of the Zagros folded belt, is classified as a region with moderate seismic hazard according to the Iranian Code of Practice for Seismic Resistant Design of Buildings (Standard No. 2800). Although the quaternary active Ahvaz fault traverses the city, can posing a significant seismic hazard in this area. This study employs an artificial statistical method to compile a comprehensive historical seismic catalog for Ahvaz City and its surrounding area. Under the assumption of stationarity, missing earthquakes are identified and incorporated into the catalog. A stochastic synthetic seismic catalog (SSSC) is constructed, including the initial catalog and added earthquakes. The seismicity parameters of the Gutenberg-Richter law are calculated, yielding values of a = 6.17 and b = 1.03. The results indicate a substantial number of missing earthquakes in the historical and early instrumental period in the Ahvaz region. This highlights the importance of incorporating these events into the seismic hazard assessment. The high number of missing earthquakes underscores the need for more comprehensive and accurate seismic hazard mapping in this region. Given its political and economic significance, Ahvaz City warrants increased attention in the fields of seismic hazard and risk assessment. The findings of this study can inform the development of more effective seismic risk mitigation strategies and enhance the resilience of the city's infrastructure and population. https://www.jsee.ir/article_722778.html This study presents an enhanced version of the concrete damage plasticity (CDP) model, widely used in the nonlinear analysis of concrete structures and implemented in ABAQUS software. Among the various models developed in this domain, the formulation proposed by Koh et al. has gained notable attention due to its use of arbitrary tensile and compressive input curves to characterize damage behavior. Building upon the foundation of the Koh et al. model, the current study introduces two key modifications: (1) replacing the original damage formulation with the Mazars damage model, and (2) incorporating energy-based stress-strain curves to define the constitutive behavior of concrete under tension and compression. The modified model is implemented as a user-defined material subroutine in ABAQUS. The model's performance is evaluated under both monotonic and cyclic loading conditions. Results demonstrate improved accuracy in capturing stiffness degradation and damage evolution, confirming the reliability and effectiveness of the proposed approach for advanced structural simulations. https://www.jsee.ir/article_724773.html This paper evaluates the effects of structure and record characteristics on the peak displacement response of low-damage structures. It firstly discusses some inconsistencies with common displacement prediction methods, and the oscillation resistance ratio (ORR) concept. Single-story structures with flag-shaped hysteresis curves with no increase in strength after the initial elastic response are then subjected to a suite of earthquake records. The structures have the same loading characteristics, but different unloading characteristics, ranging from elastic bilinear (with no energy dissipation, to fully elastoplastic. The effect of (i) scaling of shaking duration, (ii) flag-shaped hysteresis loop dissipation factor (which is associated with a lower ORR and a more pinched hysteresis), and (iii) shaking duration-period ratio, (which is the record duration, divided by structure period), on the maximum displacement was obtained for a suite of records. For low shaking duration-period ratio, maximum displacement was not sensitive to the unloading characteristics represented by hysteresis loop dissipation factor. However, for high shaking duration-period ratio, maximum displacement is increased, and this increase is significantly amplified by lower hysteresis loop dissipation factor. Initial stiffness-based method may be non-conservative for high shaking duration-period ratio and low hysteresis loop dissipation factor. Focusing on the duration-period ratio, allows more general relations to estimate inelastic structural response displacements than more traditional methods. https://www.jsee.ir/article_725153.html Recent advancements in Deep Learning (DL) have significantly expanded its application to address myriad challenges in civil and earthquake engineering. However, a notable challenge persists: the scarcity of reliable data pertinent to earthquake engineering, which may compromise the accuracy of DL-derived results. In response to this challenge, Generative Adversarial Networks (GANs) have emerged as a promising solution. Initially conceptualized to improve the training of generative models, GANs have exhibited exceptional performance and adaptability, particularly in image generation, gaining substantial recognition within the academic community. In structural engineering, the generation of synthetic ground accelerograms that conform to a specified target response spectrum is essential for conducting nonlinear dynamic analyses. This paper introduces an effective algorithm for spectral matching, facilitating the generation of numerous artificial, spectrum-compatible earthquake accelerograms from a limited set of ground motion records. The proposed algorithm represents a significant advancement in the field, addressing the critical need for robust and accurate synthetic data in earthquake engineering. Consequently, the integration of GANs into this domain not only enhances the reliability of DL applications but also paves the way for more precise and comprehensive analyses, thereby contributing to the overall progress of civil and earthquake engineering disciplines. https://www.jsee.ir/article_725217.html The selection of appropriate ground motion models (GMMs) for seismic hazard analysis is of paramount importance. In recent years, there has been a significant increase in the number of ground motion models (GMMs) at both global and local levels. These models employ seismic parameters to predict ground acceleration resulting from earthquakes within a specific region. Despite this diversity, selecting the appropriate model for a specific region has always been challenging. The selection and weighting of ground motion models (GMMs) is a complex process that has recently attracted the attention of researchers. In this study, 346 accelerograms until 2025 were utilized to rank various models and accurately predict the peak ground acceleration (PGA) in one of Iran's most seismically active regions (Zagros seismotectonic province). These accelerograms are from earthquakes with a moment magnitude (Mw) of 5.0 or greater, located within a 200 km radius of the earthquake epicenter, and for which the shear wave velocity of the site was pre-existing. In this paper, eight attenuation relationships from Saffari et al.(2012,2018), Zafarani et al.(2024) and Farajpour et al.(2019) at the local level, Campbell and Bozorgnia (2014), Boore et al. (2014), Abrahamson and Silva (2014), Chiou and Youngs(2014) and Idriss(2014) at the global level were selected and Ultimately, the performance of each model in accurately predicting peak ground acceleration (PGA) was evaluated using the log-likelihood test (LLH) and compared with observed values for the Zagros seismotectonic province. The correct selection of attenuation relationships and logical weighting coefficients for them leads to a more accurate assessment of the ground acceleration and a more precise design. https://www.jsee.ir/article_726131.html Structural analysis accuracy depends on the correct selection of ground motion time histories. Given their significant impact, a thorough understanding of the characteristics of these time histories is essential for precise analyses. Several factors influence the structure of these time histories, with proximity to the fault being one of the most important. Earthquakes are generally categorized into two groups: near-fault and far-fault, with near-fault earthquakes typically exhibiting distinctive features in their velocity records, including prominent pulses with long periods and significant amplitudes. These pulses, generated by the fault rupture mechanism, can considerably affect seismic response and structural damage. Previous research has established a link between pulse-like ground motions, the directional effects of fault rupture, and fault slip impact. These pulses, especially when fault slip propagates toward an area, appear as strong pulses in earthquake velocity records. Additionally, due to significant differences in spectral acceleration values for pulse-like ground motions, it is necessary to accurately calculate these values and incorporate them into structural dynamic analyses. In this study, using the wavelet transform method, precise pulse identification was conducted for large ground motions in Iran, and eight earthquakes were definitively identified as pulse-like. The influence of near-fault ground motion component rotation on spectral acceleration values was also thoroughly examined. The results showed significant differences in these parameter values, and in dynamic structural analyses, these values should be calculated and used to account for ground motion's varying angular effects. This study emphasizes the importance of identifying pulse-like earthquakes in different regions to develop specific seismic design regulations for near-fault areas, thereby improving structural performance against such ground motions. https://www.jsee.ir/article_726762.html Monar Jonban is one of the historical and valuable monuments in Isfahan, Iran. When one of its minarets begins to vibrate, the other one starts shaking simultaneously. Therefore, the vibration can be felt in the whole structure. This is the significant point of this historical monument. The purpose of this study is to evaluate the vibration mechanism of Monar Jonban and the reason of its shaking. Field work is used to conduct the research. After gathering data, a three-dimensional model for frequency and dynamic analysis has been made in Abaqus finite element software. In this paper the test results of International Institute of Earthquake Engineering and Seismology (IIEES) in 1994 are used to illustrate the validity of modeling as well as analysis. Besides, a modal analysis of the model of structure and cantilevered minaret has been done. Then, the generated equivalent dynamic force and also the deformation of minarets have been shown by dynamic analysis. There is a gap beside minaret; finally it has been shown that the gap improves dynamic behavior of the structure. https://www.jsee.ir/article_729071.html This article presents a parametric analysis of the dimensions and geometry of trapezoidal alluvial valleys, specifically examining the effects of valley ridge angle on the linear seismic response of alluvial valleys. This analysis uses the NASEM dynamic program, based on spectral elements, to assess responses to incoming longitudinal and shear waves. Previous research on the effects of topography on ground surface seismic response has shown the significant influence of these topographic features' geometry on seismic response. The results demonstrate that the amplification pattern and natural frequency of a trapezoidal alluvial valley are highly dependent on the valley ridge angle. As the valley ridge angle decreases, the natural frequency of the valley also decreases, trending toward the natural frequency associated with a homogeneous soil layer over bedrock under longitudinal waves, and similarly under shear waves. An increase in the parameters of valley ridge angle, valley bottom width, alluvial thickness, and longitudinal wave velocity results in a corresponding rise in the valley's natural frequency. https://www.jsee.ir/article_729935.html Some of the consequences of earthquakes are permanent ground deformations caused by fault movement and propagation of fault rupture to the ground surface. Structural seismic design codes recommend avoiding construction near active faults and establishing a setback zone from the fault lines to prevent the effects of surface fault rupture on structures. Avoiding construction across or near active faults is impossible for long structures, such as tunnels and pipelines. Therefore, appropriate measures should be taken to mitigate the fault rupture hazard. This study reviews hazard mitigation strategies for the interaction between fault and subsurface structures, which are classified into structural (flexible joints and reinforcement) and geotechnical methods (isolation layers, sliding elements, and rupture deviation). The effectiveness of these approaches is influenced by the type of fault, as well as the geometry and location of the subsurface structure. The solutions investigated and their conditions can be a guide for practical engineering. https://www.jsee.ir/article_731233.html The purpose of this article is to develop a new design framework to improve earthquake resiliency at the neighborhood level. Fooladi neighborhood in Sarpol-e Zahab city, which was severely damaged by the 2017 earthquake, was selected as a case study. The conditions of this neighborhood were studied before, during, and after the earthquake, and it was re-designed based on the criteria of resiliency. This study adopts a qualitative-descriptive approach, and six post-earthquake field visits to assess and re-design the neighborhood. Data were collected through interviews, site surveys, and observations to understand local conditions and ongoing reconstruction process. Using a comparative approach—examining the pre-, during, and post-earthquake phases— and applying resilience indicators, a design framework was developed for re-designing the neighborhood. These indicators were weighted and prioritized using the Analytic Hierarchy Process (AHP). The redesign and decision-making for the Fooladi neighborhood were guided by the prioritized indicators, allowing for minimal interventions while maximizing resiliency. It appears that the factors of urban morphology, the structure and age of buildings, the technology and quality of construction, and the lot areas are more significant in physical resilience. This approach can be applied in similar urban contexts to achieve Building Back Better (BBB) strategies. The originality of this study is proposing a step-by-step approach to enhancing urban resilience at the neighborhood scale, developed through a design framework based on indicators that are generalizable to other similar contexts. https://www.jsee.ir/article_731234.html The paper presents the results of an investigation into excessive local vibrations in a tabletop foundation for a 120 MW steam turbine generator (STG) located in northern Iran. These vibrations have persisted since the 1990 Rudbar-Manjil (Mw 7.3) earthquake. The investigation involved measuring the tabletop vibrations at several locations during normal operation of the STG unit. The measured data were analyzed in the frequency domain to extract the dynamic properties of the soil-foundation system. These properties were then utilized to calibrate a finite element model of the foundation. The results obtained from Fourier analysis of the vibration data and dynamic analyses of the foundation indicate that the excessive vibrations were primarily caused by the extremely low damping of the soil-foundation system. This low damping was attributed to the significant injection of slurry cement grout into the subsoil after the earthquake. The dynamic analyses also revealed that the excessive vibrations occurred due to near-resonant responses of local modes of vibration with frequencies close to the operating frequency of the STG unit. To mitigate the vibration problem, the installation of tuned mass dampers (TMDs) at critical locations of the foundation was proposed. A dynamic analysis of the tabletop foundation with eight TMDs demonstrated that this solution effectively mitigates the excessive vibrations. https://www.jsee.ir/article_731237.html Tehran, the capital of Iran, lies in a highly active seismic zone and is exposed to significant earthquake risk due to multiple nearby faults. Among critical urban infrastructure, gas distribution network is especially vulnerable to earthquakes, but it has not been thoroughly studied in most current risk assessments. This study proposes a probabilistic framework to evaluate the seismic vulnerability of Tehran’s gas distribution network under four major earthquake scenarios (Mosha, North Tehran Fault, Eyvanakey, and Rey faults). The methodology incorporates both aleatory and epistemic uncertainties from hazard and damage assessment of buried pipelines and pressure reduction stations. The intra-event variability of ground motion values is considered in the analysis through random sampling from spatial-cross correlation model. Similarly, the aleatory uncertainty of damage types (leak and break) in pipelines is captured in the analysis through random sampling from probabilistic distribution. Results from 1,000 Monte Carlo simulations reveal that the Eyvanakey scenario poses the highest risk, particularly in southeastern Tehran, while the Rey scenario results in minimum damage. The spatial distribution of risk underscores the importance of localized mitigation strategies. The proposed framework provides an appropriate tool for urban seismic risk assessment and resilience planning of gas utility system in seismically active cities. https://www.jsee.ir/article_733378.html Seismic data processing in engineering seismology often involves band-pass filtering, a critical step in analyzing strong-motion records. We present a systematic methodology to determine the usable frequency band—defined by a low-cut frequency (flc) and a high-cut frequency (fhc)—for each of 501 single-component SSA2 accelerograms (derived from 167 three-component records) from Iran Strong Motion Network (ISMN). Our workflow combines zero-order baseline correction, S-wave Fourier Amplitude Spectrum (FAS) analysis, noise-floor estimation, SNR-based thresholds (normalized for window length), spectral-shape evaluation (ω² model), and iterative visual inspection of filtered time series. Applying this procedure to the 501 traces, we find median limits of flc = 0.12 Hz and fhc = 14.8 Hz. Approximately 90% of the records maintain a usable bandwidth entirely within the 0.35–8 Hz range, and all records span at least one decade in frequency. These results provide a transparent and reproducible basis for selecting filter bands in strong-motion studies.