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I Earthquake Engineering and Structural Dynamics i dedicates selected issues of the I Journal i , normally no more than one issue a year, to a special topic. Each I Special Issue i normally consists of (a) original papers (submitted in response to a I Call for Papers i ) and (b) an invited State-of-the-Art or review paper, as deemed appropriate for the topic. Contributed papers for this I Special Issue i should be submitted to Wiley using the online system (http://mc.manuscriptcentral.com/eqe), with Anil K. Chopra designated as the Editor, who will provide administrative support to the Guest Editor. [Extracted from the article]

Summary: In this paper, the effect of outrigger on key seismic design parameters of tall buildings with braced or shear wall core is studied. Based on the results of modal response spectrum (MRS) and nonlinear time history (NLTH) analyses of 44 models with braced or wall core, discussed in the companion paper and pushover analysis and presented in this part, the effect of outrigger and its placement level on parameters of seismic design including response modification factor R, overstrength factor Ω0, deflection amplification factor Cd, and damping ratio of structures are studied. New local measures for Cd and Ω0 are proposed based on the NLTH results. It is observed that outrigger results in greater increase in strength and stiffness of structures with wall core than buildings with braced core, but decreases the ductility of both systems. The obtained R is less than the values given by the code in most cases. For the main structures without outrigger, using the code prescribed value for Cd underestimates the real displacement of the structures with wall core and overestimates it for those with braced core. Outrigger results in increasing Cd of structures with braced core and reduction of Cd in those with wall core. The considerable variation of two proposed measures for Cd shows the inappropriateness of application of a single value of Cd for all stories. Outrigger increased the damping ratio of buildings with shear wall core considerably. [ABSTRACT FROM AUTHOR]

The actual seismic building codes have a prescriptive nature, and they are principally aimed to guarantee a prescribed life-safety level against a design-level earthquake even if some methods have been proposed to evaluate the seismic performance of a building along its entire service life. Among these, the performance-based seismic design method permits the design of buildings with a more realistic understanding of both risk of life for occupants and economic losses that may occur in future earthquakes. On the other side, the capacity design method, providing criteria to properly spread the inelastic deformation demand between the different structural elements, allows to establish a ductile collapse mechanism avoiding undesired brittle failures. In this context, modern building codes consider the adoption of a single value for the behaviour factor q to be used in the design process. All this should be argued since, especially for buildings characterized by storeys with different uses and occupancy ratios, the adoption of a single value for q could guide the design process to a solution not minimizing the seismic loss. With reference to these aspects, the paper shows the comparison of the seismic responses of a multistorey framed building designed following two different approaches. The first approach, suggested by many international codes, follows the capacity design rules and considers a single value for the behaviour factor valid for the whole building. In this first case, the damage mechanisms could affect, theoretically, every storey of the building. The second approach, proposed here, considers instead the possibility to adopt different behaviour factors to attribute to different storeys. In this way, it is possible to concentrate and localize the most severe earthquake-induced structural damage on (few) storeys, selected by the designers. By means of the seismic performance assessment methodology, the comparison between the two building responses is provided in terms of expected losses during the whole building service life and is reported in terms of both economical loss and human life loss. The results in the paper show that, if different behaviour factors are properly selected for different storeys, the design process can provide a solution characterized by lower values of seismic loss with respect to the case of the design assuming a single-q value. [ABSTRACT FROM AUTHOR]

This paper proposes the ductility demands control of reinforced concrete frames under criticalsuccessive earthquakes using evaluation of behavior factors (R factors). The influence of RC frameperiods, PGA and magnitude of mainshocks and aftershocks is also taken into account by 10 training ideal artificial neural network (ANN) and proposing the empirical equations. Firstly, 2D RC frames are implemented in Opensees and then evaluated under as-recorded critical single and successive scenario. R factors are calculated and compared for single and successive cases. It is found that the sequences of critical records decrease R factors and capacity of RC frames about 18% and 30%, respectively. Despite what is necessitated in the seismic design codes, proposing a constant value as R factor for whole RC structure especially under single scenarios cannot lead to proper design of structures. Hence, the idealized multilayer ANNs employed to generate the empirical charts for evaluation of R factors. [ABSTRACT FROM AUTHOR]

Active faults are those faults on which movement is possible in the future. This draws particular attention to active faults in geodynamic studies and seismic hazard assessment. Here, we present a high-detail continental-scale geodatabase: The Active Faults of Eurasia Database (AFEAD). It comprises 48 205 objects stored in shapefile format with spatial detail sufficient for a 1 : 1 000 000 map scale. The fault sense, a rank of confidence in activity, a rank of slip rate, and a reference to source publications are provided for each database entry. Where possible, this information is supplemented by a fault name, fault zone name, abbreviated fault parameters (e.g., slip rate, age of the last motion, and total offset), and text information from the sources. The database was collected from 612 published sources, including regional maps, databases, and research papers. AFEAD facilitates a spatial search for local studies. It provides sufficient detail for planning a study of a particular fault system and guides deeper bibliographical investigations. This scenario is particularly significant for vast central and northern Asian areas, where most studies are available only in Russian and hard copy. Moreover, the database model provides the basis for regional- and continental-scale integrative studies based on geographic information systems (GISs). The database is available at 10.13140/RG.2.2.25509.58084 (Bachmanov et al., 2022) and via web map at http://neotec.ginras.ru/index/mapbox/database%5fmap.html (last access: 5 May 2022). Database representations and supplementary data are hosted at http://neotec.ginras.ru/index/english/database%5feng.html (last access: 5 May 2022). [ABSTRACT FROM AUTHOR]

The fundamental basis for seismic stability is clear – during an earthquake, a building must be capable of carrying gravity loads while developing large inelastic deformations and associated lateral displacements. However, structural design to achieve this performance objective is complex and depends upon multiple system parameters. In current seismic provisions, the global destabilizing effects of gravity are typically considered with simplistic models that may not properly address the actual inelastic stability response of building structures. Building systems with high ductility are used extensively in high‐seismic regions, but in moderate‐seismic regions, systems with low ductility are ubiquitous. The inelastic responses of low‐ductility and high‐ductility systems are starkly different, and life safety must be ensured across this wide variation in behavior. This paper will discuss foundational seismic stability principles and explore the range of inelastic response that is associated with conventional seismic systems and novel next‐generation systems. Results from large‐scale component tests, full‐scale frame tests and numerical earthquake simulations will be used to demonstrate several important concepts: (1) high‐ductility response is an insufficient, and not always necessary, condition for seismic stability; (2) the most critical parameter for seismic stability is persistent secondary stiffness; (3) emerging technologies like recentering, which limit damage, are promising solutions for enhanced seismic resilience. [ABSTRACT FROM AUTHOR]

In this paper, the shaking table tests and finite element analyses were conducted on the traditional thermal power plant main building and the thermal power plant main building with BRBs, respectively. The differences in torsional resistance between the two structural systems were studied, and the suppression effect on the displacement field distortion of the plane consisting of crane and tracks through adding BRBs in the thermal power plant main building was discussed. The study shows that after adopting a buckling-restrained brace in a thermal power plant main building, the damage and torsional response of the structure under an earthquake can be reduced, the occurrence of inelastic torsion can be effectively blocked, and the translation-torsion coupling effect can be reduced. At the same time, it can reduce the distortion amplitude of the displacement field of the plane consisting of crane and tracks and play a key role in improving the reliability of roof truss, crane, coal bucket, and low-ductility connectors, and it also facilitates the realization of performance-based seismic design. [ABSTRACT FROM AUTHOR]

The recent devastating earthquakes have caused severe physical, social, and financial damage worldwide and indicate that many existing buildings, especially in developing countries, are not designed to withstand seismic hazards and resulting vulnerabilities to earthquakes. It is difficult, time-consuming, and costly to investigate and inspect all the existing buildings in detail before an earthquake, especially in urban areas. Therefore, rapid methods for evaluating the vulnerability of buildings have attracted the interest of researchers. This paper investigates the seismic susceptibility through the combination of buildings' geometrical attributes that affect the vulnerability of buildings and further extended into having foresight into the damage state of reinforced concrete (RC) buildings using artificial neural network (ANN). For this purpose, a multi-layer perceptron (MLP) network has been trained and optimized using two different databases of damaged buildings from the Nepal and Ecuador earthquakes. The results show the practicability and efficacy of the selected ANN approach for classifying actual damage grade based on structural damage, which the workflow can be followed and applied into other data from other regions for the detection of highly vulnerable buildings. A prototype of a smartphone app and its implementation was later introduced for data collection and vulnerability assessment purposes based on the proposed method. [ABSTRACT FROM AUTHOR]

This paper is a review of our work, an experimental study and simulation of seismic fields in volcanic structures using vibrators as sources of elastic waves. We review the results of experimental studies of mud volcanoes carried out by the Institute of Computational Mathematics and Mathematical Geophysics (ICM&MG) of the Siberian Branch (SB), Russian Academy of Sciences (RAS); by the Institute of Physics of the Earth (IPE), RAS; and by the Kuban State University in the Taman mud-volcanic province using vibrators. We have carried out mathematical simulation in heterogeneous geophysical media to refine the information on the structure of the object under investigation, as well as on the distinguishing features of the seismic field. We have developed a mathematical approach to deal with the simulation of vibroseismic probing of mud volcanoes with arbitrary geometries incorporating knowledge of deep-seated faults, overlapping layers, and so on. Numerical techniques were used to solve sets of equations in elasticity theory and to develop parallel algorithms, program packages, as well as carrying out numerical experiments in high-performance computational systems. We present results from calculations of the seismic field for the source zone of the Shugo mud volcano. This paper describes 3D and 2D geophysical models developed for this study and the results of simulation for the seismic field of the Karabetova Gora mud volcano and for the Elbrus magmatic volcano. It is shown that the approach developed here using active vibroseismic techniques can be successfully used in practice to refine the seismic field, the deep structure of geophysical models, and to study the effects exerted by the geometry of a magma chamber and by the presence of erupting channels on data acquired by an observation system on the ground surface. These studies prove that vibroseismic sources with high accuracies of periodic excitation can be used to study volcanic structures and to conduct active monitoring of volcanic activity. [ABSTRACT FROM AUTHOR]

Nonlinear response history analysis (NLRHA), or so-called "nonlinear time history analysis", is adopted by practicing structural engineers who implement performance-based seismic design and/or assessment procedures. One important aspect in obtaining reliable output from the NLRHA procedure is the input ground motion records. The underlying intention of ground motion selection and amplitude-scaling procedures is to ensure the input for NLRHA is representative of the ground shaking hazard level, for a given site and structure. The purpose of this paper is to highlight the salient limitations of the ground motion selection and scaling requirements in Sections 5.5 and 6.4 of the New Zealand (NZ) loading standard NZS 1170.5 (2004). From a NZ regulatory perspective; there is no specific framework for seismic hazard analysis and ground motion selection (thus self-regulation is the current norm). In contrast, NZS 1170.5 contains many prescriptive requirements for scaling and applying records which are challenging to satisfy in practice. Also discussed within, there are implications for more modern guidance documents in NZ, such as the 2017 "Assessment Guidelines" for existing buildings, which cite NZS 1170.5, a standard which is at least 16 years old (draft issued in 2002). To emphasize the above issues with NZS 1170.5, this paper presents a summary of the more contemporary approaches in the US standards ASCE 7-16 (new buildings) and ASCE 41-17 (existing buildings), along with some examples of the more stringent US requirements for Tall Buildings. [ABSTRACT FROM AUTHOR]

Seismic exploration is an oil exploration method by utilizing seismic information. Useful reservoir parameter information can be gained through inversion of seismic information to effectively carry out exploration work. Prestack data are characterized by large data size and rich information. Rich reservoir parameter information can be obtained through inversion of prestack data. Due to mass prestack seismic data, existing single computer environment cannot satisfy computation requirement of huge data size. Thus, an efficient and fast method is urgently needed to solve the inversion problem of prestack seismic big data. Since local optimum may be easily caught when genetic algorithm is used to optimize elastic parameters, the inversion effect is not obvious. In particular, the optimization effect for the density parameters is not good. An intelligent optimization algorithm is proposed in this paper for elastic parameter inversion of prestack seismic data. The algorithm improves genetic manipulation. The improved algorithm has been used for model trial for log data, and good inversion effect has been achieved. The inverted elastic parameters well fit with the log curve of the theoretical model. The improved algorithm effectively improves the inversion accuracy of density parameters. In this paper, the algorithm has been implemented on Spark model, and the results show that the parallel model can effectively reduce operation time of the algorithm. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Geotechnical Journal is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Tennessee has been known as The Volunteer State since the War of 1812 when thousands of Tennesseans enlisted in response to Governor Blount's call for volunteers. Similarly, the state of Tennessee recently adopted the International Building Code, 2012 Edition, without amendments, expecting its exempt counties and cities to voluntarily follow suit. The seismic design sections in building codes have been one of the most controversial sections in code adoption and implementation with many voluntary adopters trying to amend seismic sections or eliminate them entirely. This is due to the lack of earthquake occurrences and the perceived cost of seismic design, an ongoing problem in the central and eastern United States for at least the last 50 years. However, although not a technical paper, this paper discusses the history of seismicity and seismic design/assessment, i.e., earthquakes and earthquake engineering in Tennessee, even before seismic design was accepted and implemented in Tennessee building codes. The paper discusses many issues that have arisen when (1) determining the seismic hazard, (2) developing the seismic designs of new structures, systems, and components (building design issues), and (3) conducting seismic assessments of existing structures, systems, and components. [ABSTRACT FROM AUTHOR]

Copyright of Revue Française de Géotechnique is the property of EDP Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

With the rapid development of urbanization, high‐rise buildings have risen from the ground, but in the long‐term use of the building, there will be settlement, tilt, displacement, and other deformations, which will seriously bring disasters. At present, there is a lack of an application‐level settlement monitoring system for the monitoring of these buildings, and there are problems of low intelligent monitoring level and low monitoring accuracy, so this paper proposes a double‐loop monitoring system based on laser collimation. The system combines distributed computing, spot image processing, embedded computing, laser collimation technology etc., to design settlement monitoring equipment and corresponding software. Finally, the data processing is carried out by the double‐loop calculation algorithm to obtain the sedimentation amount of the analyte. The test results show that the whole system can be intelligently and accurately monitored, and the monitoring accuracy can reach the millimetre level. [ABSTRACT FROM AUTHOR]

The post‐earthquake recovery of a community depends on the ability of important buildings to perform their functions. Lifeline and other critical buildings that meet a predictable enhanced seismic performance increase the community's disaster risk management capacity. In prescriptive force‐based design standards, the seismic design force for these buildings is typically enhanced using an importance factor depending on the risk category. The present paper proposes an innovative framework based on performance‐based seismic design (PBSD) principles using risk‐targeted importance factors suitable for use with prescriptive standards. The framework decouples probabilistic assessments of building typologies to experts, while the structural designers can continue the conventional design approach. The framework explicitly considers probabilistic seismic demand, uncertainty in the performance of the building, and the inter‐building variation within a particular building typology in seismic performance. Six special reinforced concrete (RC) frame buildings conforming to Indian standards are selected to illustrate the framework. Sensitivity studies on parameter selection are used to establish the framework's robustness. An expression for the importance factors is also proposed. The use of the proposed importance factor expression is shown to meet a wide range of risk targets corresponding to different performance levels. The paper also proposes design factors for enhanced performance objectives suitable for the risk‐targeted prescriptive design. Further, the framework is implemented to estimate the seismic risk associated with existing building typology conforming to prevalent design standards. The assembly‐ and critical‐category RC buildings are found to require higher importance factors for achieving enhanced performance objectives than currently prescribed. [ABSTRACT FROM AUTHOR]

Because of its special material composition, formation environment and special structure, special soil usually shows different seismic response characteristics from general soil, and sometimes causes serious seismic disasters. Therefore, the study of seismic response characteristics of special soil has important practical significance for engineering construction and disaster prevention in special land areas, and a site seismic response analysis is an important way to study the impact of site conditions on ground motions. Based on the existing research work, the uniform and single ideal soil layer profiles of three special soils are established, and the seismic response analysis program of the soilquake soil layer is used to study the effects of the dynamic shear module ratio, damping ratio and shear-wave velocity of soft soil, loess and laterite on the characteristic period and platform value of the design response spectrum under different input ground motion intensities. At the same time, three typical actual drilling data values are selected to establish the calculation model of the site soil layer. On the basis of the seismic response analysis and calculation of the soil layer, three special soil dynamic characteristics are compared from the aspects of peak acceleration and characteristic parameters. Based on the research results of this paper, the recommended values of the dynamic shear module ratio and damping ratio of three special soils are given. This work has important reference value for seismic design in soft soil, loess and laterite areas, and also enriches the research results of soil dynamic parameters. [ABSTRACT FROM AUTHOR]

Proper regulative in earthquake risk reduction, hazard assessment, earthquake resistant design and construction of structures, should be under perpetual improvement. They are mainly the result of earthquake study and analysis of post-seismic effects. In this context, a new frame for seismogram analysis is proposed, based on its decomposition into elementary and single (positive and negative) fluctuations (EF/SF). Decomposition enables rearrangement, both providing the frame for defining new attributes, where several main ones are proposed and elaborated in the paper: fan diagram of EFs structural axes; R- or RQ-envelope, formed over positive and over negative peaks of ordered SFs; two forms of difference functions of positive and negative R/RQ-envelopes, as a measure of seismogram's (a)symmetry, in respect to t-axis; distributions of SFs durations. Several others are in perspective. Analogy between R-envelope and seismogram's spectrum is considered from the aspects of arranged elements, and asymptotic behavior of these two functional attributes. More objective definition of seismogram duration is proposed, determined by linear regression across the scatter plot of SFs peaks. R-envelope showed itself as an invariant in the seismogram population, and the distribution of SFs durations as well. Results are presented through extensive graphics, backed with mathematical description. Thorough discussion of the concept and results is given. [ABSTRACT FROM AUTHOR]

This paper for the first time improved a Robust Multi-Output machine learning regression model for seismic hazard zoning of Turkey, Iraq and Iran using constructed 3-D shear-wave velocity (Vs), seismic tomography dataset model for the crust and uppermost mantle beneath the study area. The focus of this paper's opportunity is to develop a scientific framework leveraging machine learning that will ultimately provide the rapid and more complete characterization of earthquake properties. This work can be targeted at improving the seismic hazard zones system ability to detect and associate seismic signals, or at estimating other seismic characteristics (crust acceleration and crust energy) while traditionally, methods cannot monitor the earthquakes system. This work has derived some physical equations for extraction of many variables as inputs for our developed machine learning model based on a reliable understanding of the tomography data to physical variables by preparing huge dataset from different physical conditions of crust. We have extracted the velocity values of the shear waves from the original NETCDF file, which contains the S velocity values for every one km of the depths of the crust for the study area from one km down to the uppermost mantle beneath the Middle East. For the first time, this study calculated new seismic hazard parameter called Peak Crust Acceleration (PCA) for seismic hazard analysis by considering the transmitted initial seismic energy through the Earth's crust layers from hypocenter. All machine learning algorithms in this study wrote in python language using anaconda platform the open-source Individual Edition (Distribution). [ABSTRACT FROM AUTHOR]

A buckling-restrained knee-braced frame (BRKBF) is an efficient structural system utilizing short buckling-restrained braces (BRBs) as knee bracing elements. Because of the shorter yielding core length compared to those of conventional BRBs, one of the key parameters concerning the performance of this system is the low cycle fatigue cumulative damage of the BRBs. This paper presents a seismic design method considering the cumulative damage, performance evaluation, and collapse assessment of 3-story, 6-story, and 9-story archetype BRKBFs. An energy-based plastic design method was utilized to design the example frames. The frames were then evaluated by nonlinear static analysis and multiple-stripe analysis (MSA). The results indicated that BRKBs were able to accommodate seismic motions with limited damage. The validity of the design methodology considering cumulative damage was also confirmed. [ABSTRACT FROM AUTHOR]

Buckling restrained brace frames (BRBFs) exhibit exceptional lateral stiffness, load-bearing capacity, and energy dissipation properties, rendering them a highly promising choice for regions susceptible to seismic activity. The precise and expeditious prediction of seismic demands on BRBFs is a crucial and challenging task. In this paper, the potential of artificial neural networks (ANNs) to predict the seismic demands of BRBFs is explored. The study presents the characteristics and modelling of prototype BRBFs with different numbers of stories and material properties, utilising the OpenSees software (Version 2.5.0) for numerical simulations. The seismic performance of the BRBFs is evaluated using 91 near-fault pulse-like ground motions, and the maximum inter-storey drift ratio (MIDR) and global drift ratio (GDR) are recorded as a measure of seismic demand. ANNs are then trained to predict the MIDR and GDR of the selected prototypes. The model's performance is assessed by analysing the residuals and error metrics and then comparing the trend of the results with the real dataset. Feature selection is utilised to decrease the complexity of the problem, with spectral acceleration at the fundamental period (T) of the structure (Sa), peak ground acceleration (PGA), peak ground velocity (PGV), and T being the primary factors impacting seismic demand estimation. The findings demonstrate the effectiveness of the proposed ANN approach in accurately predicting the seismic demands of BRBFs. [ABSTRACT FROM AUTHOR]

In earthquake-prone areas, pile-anchor structures are widely employed for slope reinforcement due to their reliable performance. Current research has primarily focused on static and quasi-static analyses of slopes reinforced by using pile-anchor structures, with limited investigation into their dynamic response. In this work, the finite element method (FEM) is used to study the dynamic behavior of a pile-anchor slope system, and the extended finite element method (XFEM) is used to simulate the progressive failure processes of piles. Three different reinforcement schemes, which include no support, pile support, and pile-anchor support, are considered to examine the performance of the pile-anchor structure. The simulation results suggest that the pile-anchor structure displays a reduction of 39.6% and 40.6% in the maximum shear force and bending moment of the piles, respectively, compared to the pile structure. The XFEM is utilized to model the progressive failure process of the piles subjected to seismic loading. We find that crack initiation in the pile body near the slip surface, for both the pile supported and the pile-anchor supported conditions, occurs when the peak ground acceleration arrives. Crack growth in the piles completes in a very short period, with two distinct increments of crack area observed. The first increment occurs when the peak ground acceleration arrives and is significantly larger than the second increment. Consequently, for the seismic design of piles, it is necessary to strengthen the pile body around slip surfaces. The novelty of this paper is that we realize the simulation of crack initiation and propagation in piles subjected to seismic loading. [ABSTRACT FROM AUTHOR]

This paper's main aim was to explain the process of characterising the structural over-strength factor (R), seismic behaviour factor (Q), and the effective elastic stiffness, Keff, of cantilever-reinforced concrete (RC) urban bridge columns with solid circular cross-sections for use in seismic design under the Serviceability Limit State (SLS). Similarly, mathematical models have been proposed to determine the average values of effective stiffness and seismic response modification factors suggested for cantilever-reinforced concrete bridge columns at SLS. This is because multiple design codes stipulate that cantilever RC bridge columns must meet the SLS requirements. Therefore, to comply, the lateral displacement ductility demand must not exceed unity after a moderate or small earthquake. While the behaviour of the materials remains in the elastic range, this performance criterion can be conservative. If the materials undergo small deformations, the slight damage can be quickly repaired to meet the SLS. [ABSTRACT FROM AUTHOR]

The current paper's goal is to investigate how dynamic interaction phenomena and material nonlinearities affect the dynamic behavior of a concrete gravity multi-arch dam in terms of maximum displacements, natural stresses, principal stresses, and Von Mises stresses when subjected to seismic excitation. Utilizing ANSYS APDL software, linear and nonlinear transient analysis using the finite element method was employed to analyze the interaction between the dam and its rock foundation. As a case study for this work, the multiarch Beni-Bahdel dam was selected, and the seismic excitation used data from a simulated earthquake. The direct method is employed to model the interaction between the multi arch dam and the rock foundation using two approaches; the fixed base approach and the mass foundation approach. Six finite element models were performed using ANSYS code, "linear dam-fixed support", "nonlinear dam- fixed support", "linear dam-linear rock foundation" "nonlinear dam-linear rock foundation", "nonlinear dam-nonlinear rock foundation" and "linear dam-nonlinear rock foundation". The bilinear kinematic hardening model is employed to represent the nonlinearity of both dam body and rock foundation. The results obtained are compared to understand the effect of both material nonlinearities and interaction phenomenon on the dynamic behavior of the studied dam. In contrast to the nonlinearity of the rock foundation material, it is concluded that the nonlinearity of the concrete dam material has a significant impact on the behavior of the system. [ABSTRACT FROM AUTHOR]

Base isolation applications are becoming popular in the seismic design of resilient structures and infrastructures. Even though the response of the bearings is widely studied under cyclic displacements, limited information is available for bearing response under sustained lateral loads. These types of loads can develop sustained lateral displacement in the bearing. During the holding time under sustained lateral displacement, the creep or stress relaxation may significantly change the properties of the bearings and may affect the response in the reloading stage. This research paper aims at assessing the influence of short-term lateral creep on the hysteretic response of rubber bearings, and ball rubber bearings. To this end, experimental testing on different elastomeric bearings under imposed lateral displacement is performed. For each device, the lateral response is measured, and the advantages and disadvantages are discussed in terms of strength, stiffness, energy dissipation and equivalent damping. The loss of load under sustained lateral displacement is experimentally assessed and the effects of creep in the design procedure of a base isolated system are discussed. [ABSTRACT FROM AUTHOR]

The response displacement method (RDM) is recommended for the seismic analysis of underground structures in the transverse direction for many codes, including bases for design of structures-seismic actions for designing geotechnical works (ISO 23469) and code for seismic design of urban rail transit structures (GB 50909-2014). However, there are some obvious limitations in the application of RDM. Springs and the shear stress of the soil could be approximately evaluated for the structures having a simple cross section, such as rectangular and circular structures. It is necessary to propose simplified seismic analysis methods for structures with complex cross sections. This paper refers to the idea of RDM and proposes three generalized response displacement methods (GRDM). In GRDM1, a part of the soil surrounding a structure is selected to generate a generalized underground structure with a rectangular cross section, and the same analysis model as RDM is applied to analyze the responses of the structure. In GRDM2, a hollow soil model without a generalized structure is used to compute the equivalent load caused by the relative displacement of the soil, and the soil-structure interaction model is applied to calculate the responses of the structure. In GRDM3, a continuous soil model is applied to compute the equivalent load caused by the relative displacement and shear stress of the soil, and the soil-structure interaction model is applied to analyze the responses of the structure, which is the same as the model used in GRDM2. The time-history analysis method (THAM) is used to evaluate the accuracy of the proposed simplified methods. Results show that the error of GRDM1 is about 20%, while the error is only 5% for GRDM2 and GRDM3. Among the three proposed methods, GRDM3 has obvious advantages regarding calculation efficiency and accuracy. Therefore, it is recommended to use GRDM3 for the seismic response analysis of underground structures that have conventional simple or complex cross sections. [ABSTRACT FROM AUTHOR]

The paper presents the structural analysis and critical evaluation of the modelling process of a high‐bay cold storage warehouse structure, which is a clad rack structure, composed of cold‐formed steel members, with different profile shapes and thicknesses. A major issue of the global structural analyses of these types of steel structures is the mixed application of design rules since the design is governed by racking structural rules, seismic design rules and cold‐formed steel design rules. To manage this problem, the structure's spatial model was divided into characteristic partial models, and spring supports were used to make the behavior of the partial models more realistic. The influence of the gravity loads (self‐weight, show), horizontal loads (wind and seismic action), geometrical imperfections, and loads induced by the temperature variation on the structure was investigated in the structural design. Even the wind actions resulted as dominant, some uncertainties related to the seismic analysis of these structures are presented in the paper. [ABSTRACT FROM AUTHOR]

Self-centering shear wall systems (SCSWSs) exhibit superior seismic capacities with low-damage and self-centering features. However, the cumulative effect under long duration earthquakes would diminish robustness of the system and lead to increased unrecoverable damage. Thus, it should be considered in seismic designs for SCSWSs. This paper applies an energy-based design procedure (EBDP) to SCSWSs in accordance with the Chinese code. A step-by-step design procedure is presented to conduct multi-level designs for SCSWSs using EBDP, while detailed explanations are elaborated corresponding to SCSWS features. A design example is presented to verify the applicability of the EBDP in SCSWSs. The performance of the designed SCSWS is then assessed and compared with a SCSWS designed by the direct displacement-based design method. Results show that the EBDP designed structure has 13% enhanced strength capacity with better controllability in the damage development. The damage index equaling to 0.35 and 0.46 are quantified with two groups of earthquakes, which consists with the performance demands. In addition, deformations are in good agreement with the design objectives, implying reasonable application of the EBDP in SCSWSs. [ABSTRACT FROM AUTHOR]

Currently, most of methodologies available to evaluate the seismic performance of buildings use as index maximum interstory drifts. However, recent earthquakes have evidenced the need to develop performance levels that incorporate seismic resilience concepts to evaluate the level of post-seismic functionality of buildings and their capacity to recover functionality. Furthermore, such performance levels should explicitly consider the performance of structural, non-structural elements and contents. For this purpose, this paper proposes a set of six performance limit states for office-type buildings, in which the seismic performance of structural, non-structural elements and contents is explicitly considered. Each of these limit states is associated with a set of probable events that generically determine its recovery of functionality (e.g., post-seismic inspection and management of financial resources). To exemplify the proposed scheme a seven-story reinforced concrete building with unreinforced infill masonry walls and located in Mexico City is evaluated. The results obtained suggest that the building has a significant probability of experiencing loss of functionality due to the damage suffered mainly by the non-structural elements and contents. This indicates that modern seismic design codes, as that used for this study, accomplish their main objective, which is to reduce the probability of collapse and to prevent the loss of human lives. However, these results also demonstrate that the main objective of decision makers when designing such buildings, which is to be functional for one or several needs, is not achieved. [ABSTRACT FROM AUTHOR]

In order to improve the communication performance between different equipment in the seismic detection system, a wireless network system with MIMO (Multiple Input and Multiple Output) characteristics was designed and applied in the paper. On the basis of 5G communication, a new data conversion and transmission model was built, which can improve the rate of signal transmission and reduce the bit error rate and power consumption. For the purpose of power optimization, the overall framework of the network system was improved, of which power characteristics and performance were verified. The conjugate beam was normalized, and the cumulative distribution function under different downlink rates was obtained based on the maximum minimum power control scheme. In order to verify the energy-saving effect of the design, the ADC (Analog-to-Digital Conversion) power model is introduced. Through simulation analysis, the change rules of spectrum efficiency and energy efficiency under different network nodes were obtained. The results show that the normalized conjugate beam can be less affected by the transmission nodes, and the power control is more reliable under the same conditions. The research and application of this subject can significantly improve the wireless communication performance of the seismic monitoring system, reduce the power consumption of network equipment, improve the data transmission efficiency, and provide strong technical support for seismic prediction and data analysis. Through the test of artificial earthquake, it is verified that the communication scheme designed in this paper has higher transmission efficiency and lower bit error rate, and is very suitable for the long-distance transmission of seismic signals. [ABSTRACT FROM AUTHOR]

The aim of this paper is to present a performance-based method to estimate uniform risk spectra (URS) for the seismic design and assessment of structures. These spectra, computed with the proposed methodology, provide the lateral capacity (in terms of spectral acceleration) that should be given to a structure, characterized by a reference single degree of freedom system, to achieve a predetermined exceedance rate of economic loss. This procedure involves the seismic hazard assessment necessary to define a seismic design level consistent with the accepted loss value, using a large enough number of synthetic seismic records of several magnitudes, which were obtained by means of an improved empirical Green function method. The statistics of the expected losses of a reference single degree of freedom system are obtained using Monte Carlo simulation, considering the seismic demand and the lateral strength of the structure as random variables. The method is divided into two main stages: (1) definition of the seismic hazard at the site of interest and (2) the probabilistic analysis of the seismic performance in terms of an economical loss ratio of nonlinear SDOF. To illustrate the proposed methodology and, subsequently, to validate it, a URS was computed for a site located in the Mexico City lake-bed zone, and its use in the design of three reinforced concrete frames is shown. The results show that the proposed spectra provide a sufficient approximation between the seismic risk level considered in the seismic design and that of the designed structure. It is concluded that the proposed procedure is a significant improvement over others considered in the literature and a useful research tool for the further development of risk-based earthquake engineering. [ABSTRACT FROM AUTHOR]

The seismic design of structures is crucial for preventing structural collapse and safeguarding human lives. Buckling-restrained braces (BRBs) have emerged as effective seismic protection devices due to their high stiffness, strength, and exceptional energy absorption capabilities. Typically, a conventional BRB consists of a steel core surrounded by concrete-filled steel tubes, with a separation mechanism ensuring axial-only deformation of the core. However, researchers have been increasingly focusing on developing innovative BRB designs with enhanced performance, incorporating different materials and configurations. This paper presents a comprehensive analysis of the development of novel BRBs introduced in the past 15 years. A systematic review approach is adopted, and the selected articles are categorized based on the shapes, materials, and compositions of the BRB components. Although carbon steel has been widely used in numerous studies, its susceptibility to corrosion and its potential impact on the hysteretic behavior of BRBs remain unexplored. Consequently, future research prospects are identified, highlighting the significance of employing anti-corrosive materials in fabricating BRBs to ensure their stable seismic performance under harsh environmental conditions. Investigating novel materials and configurations can lead to the creation of more robust and corrosion-resistant BRBs, thus enhancing the safety and longevity of structures in earthquake-prone areas. [ABSTRACT FROM AUTHOR]

Composite plate shear walls/concrete-filled (C-PSW/CFs), also known as SpeedCore systems, are a relatively new structural member in American codes and standards. Prior research has focused primarily on C-PSW/CF walls with either flange/closure plates or filled composite members as boundary elements. Walls without boundary elements have also been studied, but they are no longer permitted by the American Institute of Steel Construction (AISC 341-22). The reason is that composite walls without boundary elements do not provide adequate ductility for seismic design. This paper presents the results of experimental and numerical studies conducted to evaluate the cyclic lateral load behavior of C-PSW/CFs using hot-rolled structural steel members as boundary elements. The steel web plates of the C-PSW/CF specimens were connected to each other using threaded tie bars with double nut connections. Composite interaction between the steel and concrete infill was achieved using the tie bars and additional shear studs welded to the boundary elements. The composite walls were embedded and anchored to reinforced concrete foundation blocks using welded deformed bar anchors. The experimental investigations focused on the cyclic lateral load-drift responses including test observations and limit states, moment-rotation response of the plastic hinge and the section moment-curvature relationship, overall lateral stiffness, strength, and displacement ductility. The experimental results show that the specimens exceeded their nominal flexural capacities calculated using the plastic stress distribution method or fiber-based section modeling using measured material properties. The specimens had plastic hinge rotation capacity greater than 0.028 rad. and displacement ductility ratio greater than 5.2. Detailed 3D nonlinear inelastic finite element models and simpler fiber-based macro models of the tested specimens were developed and benchmarked using experimental results. The detailed 3D finite element models can reasonably simulate the global and local behavior of the specimens, and are recommended for conducting further parametric studies of composite wall design details. Simpler fiber-based macro models can efficiently simulate the cyclic lateral load behavior of the specimens, and are recommended for modeling C-PSW/CFs while simulating the behavior of multi-story building structures. [ABSTRACT FROM AUTHOR]

This paper describes the relationship between bedrock depth (D) and site fundamental frequency (f0) in the Nakdonggang delta region in the southeastern part of the Korean peninsula. We collected borehole logs to confirm the thickness of the sediments and estimated the f0 at over 200 locations across the delta using the horizontal-to-vertical spectral ratio (HVSR) method. We developed an f0 map of the study area by spatially interpolating the f0 values using the Ordinary Kriging method. The bedrock depth in the main delta showed a power-law dependence on the f0. The derived f0–D model predicted much shallower bedrock depths compared with similar studies from other parts of the world. This was attributed to the fact that the Nakdonggang delta region is composed of relatively low Vs Holocene sediments. With an f0 map, the derived model could enable a quick estimation of the bedrock depth, which could help to determine the site class in the Nakdonggang delta region according to the Korean Seismic Design Standard (KDS 17 10 00). [ABSTRACT FROM AUTHOR]

This paper presents the results of an experimental program involving shake table testing of two full-scale reinforced concrete frame buildings. These tests were conducted to investigate the effectiveness and reliability of a newly proposed servo-hydraulic Active Mass Damper (AMD) that can be designed to enhance the target seismic performance of a building at multiple earthquake intensity levels. The two nominally identical case-study buildings were intentionally designed to exhibit a "soft story" mechanism at the first level when subject to ground shaking of sufficient intensity, but one was equipped with the newly proposed AMD, installed on the roof. The two specimens were then subject to the same loading protocol consisting of a ground shaking sequence of varying intensity, with the seismic input consisting of a selected natural ground motion.The experimental results demonstrated that the proposed AMD is extremely effective at enhancing building seismic performance. Specifically, the AMD provided peak displacement reductions in the order of 70% and was shown capable of absorbing more than 60% of the total input energy. As a consequence, the un-retrofitted structure suffered nontrivial structural and non-structural damage, while the AMD-retrofitted building remained virtually undamaged at all shaking intensities considered. [ABSTRACT FROM AUTHOR]

This paper presents a contribution to reviewing the most common seismic design procedures of CLT buildings and their implications on structural features and technological solutions. Attention is particularly focused on the overall seismic performance, damage tolerance, construction costs and environmental impact. It is intended as a baseline for a more comprehensive study, thus the assessment is made with reference to a real building, representative of a class of common buildings recently designed and erected in many Italian regions exposed to low and moderate seismic hazards. As usual, the analysis was carried out according to a two-dimensional model of the panels, assumed to be elastic, varying the type of connections at the base, the presence of pre-stressing steel bars for rocking control and dissipative devices. The main outcomes of the study can be summarized as follows: (i) the structural seismic behavior of CLT buildings is significantly influenced by the structural schemes adopted for walls and connections; (ii) construction costs and environmental impact decrease whenever damage tolerance is accounted for in design procedures. [ABSTRACT FROM AUTHOR]

The cold-formed steel shear wall with steel sheathing has gained increasing popularity due to its excellent shear capacity. To extend the applicability of this system to multi-story residences, aside from experimental investigations on the shear walls, it is essential to conduct a comprehensive study on the seismic performance of buildings. In this paper, numerical simulations were conducted on specimens subjected to monotonic and cyclic loading. Subsequently, seismic analysis of mid-rise building models was also carried out to investigate the influence of the proposed shear wall on building seismic performance. The research findings indicate that this study's modeling method can effectively simulate the shear performance of the proposed shear wall under monotonic and cyclic loading. In addition, the proposed shear wall significantly enhances the structural stiffness and improves the seismic performance of the structure under seismic action. [ABSTRACT FROM AUTHOR]

The next edition of the fib Model Code for concrete structures, Model Code 2020 (MC2020), is under development with the aim of issuing a first partially harmonized draft for comment in early 2023. MC2020 is a single code dealing with both new and existing concrete structures, that is both the design of new structures and the various activities associated with the assessment, interventions upon and life‐cycle management (LCM) of existing concrete structures. The paper outlines the overarching sustainability framework and the performance‐based or outcomes‐based approaches (PBA) adopted by MC2020. There is a pressing need to reduce barriers to the evolution in concrete construction materials and the technical aspects of design and the LCM of existing structures, in order to meet pressing climate change drivers and the goal of achieving lower carbon construction. MC2020 also addresses significant advances made on a wide range of issues including those relating to structural design and analysis methods, seismic design and assessment procedures, durability, structural monitoring, service life design, structural assessment through‐life and making interventions to adapt existing structures or enhance their performance or extend their useful life. [ABSTRACT FROM AUTHOR]

Composite Plate Shear Walls−Concrete Filled (C‐PSW/CF) are an innovative seismic force resisting system recently adapted for building applications. The walls consist of parallel steel faceplates connected with tie bars and filled with concrete. This paper summarizes the results of a recent FEMA P695 study completed to verify seismic design parameters for uncoupled C‐PSW/CFs with rectangular flange plate boundary elements. Seven archetype structures were: (i) designed, (ii) modeled using a benchmarked fiber‐based finite element analysis approach, (iii) subjected to nonlinear pushover analysis, (iv) and to incremental nonlinear dynamic analysis to failure for 22‐sets of scaled ground motions, and (v) the results were statistically analyzed to assess performance. These structures ranged from three (3) to twenty‐two (22) stories and included both planar and C‐shaped configurations. As part of this design process, recommendations for stiffness approximations for linear analysis of C‐PSW/CFs were developed. Additionally, these nonlinear incremental dynamic analysis results were post‐processed to determine the rotation and strain demands at the base of these structures at the design basis, maximum considered, and failure level earthquakes. These results showed that the rotation and strain demand at failure level earthquakes were comparable regardless of the ground motion. Ultimately, this FEMA P695 approach verified the R factor of 6.5, Cd factor of 5.5, and Ω0 of 2.5 for C‐PSW/CFs with boundary elements. [ABSTRACT FROM AUTHOR]

A fiber-reinforced polymer (FRP) confined engineered cementitious composite (ECC) column as a new high-performance composite member achieves significant ductility. Understanding its cyclic behavior is necessary to guide seismic design. This paper presents an experimental study on the compressive behavior of large rupture strain (LRS) FRP and traditional glass FRP (GFRP) jacketed ECC cylinders subjected to full and partial cyclic loadings. Effects of FRP confinement level, FRP type, and loading scheme on the failure pattern, stress–strain relationship, ultimate condition, plastic strain, and stress deterioration ratio were examined. Existing equations for plastic strain and stress deterioration ratio of the envelope and internal cycles were evaluated. Based on the experimental results, new calculation formulas were derived for the plastic strain and stress deterioration ratio. A threshold involving partial unloading/reloading factors was determined to define the effective cycles. In addition, a cyclic model composed of a monotonic envelope model and an unloading/reloading model was developed for estimating the stress–strain hysteresis loops of both GFRP- and LRS FRP-confined ECC cylinders. [ABSTRACT FROM AUTHOR]

This paper evaluated the progressive collapse robustness of steel intermediate moment-resisting frames (MRFs) under different fire-induced column failure scenarios. For this purpose, 3-, 7-, and 12-story intermediate MRFs were modeled numerically and analyzed under different gravity and fire loads. The effects of the seismic design requirements, number of stories, gravity load ratio (utilization ratio), and redundancy and position of the heated column were discussed. Because the investigations included models with different number of stories and different seismic to gravity load ratios, the results can be applied for a wide range of IMFs. The results show that none of the studied frames in the high seismic zone with a low gravity loads ratio experienced progressive collapse under any of the considered fire scenarios. However, by increasing the ratio of gravity loads in frames, the vulnerability to progressive collapse was increased. This suggests that in areas with a lower risk of environmental lateral loads, where MRFs generally are designed for gravity loads and smaller lateral forces, the progressive collapse robustness of MRFs under fire-induced column failure should be given serious consideration. In addition, the results show that the possibility of progressive collapse under the fire-induced column failure scenarios in the first story of low-rise frames is more than that in the first story of high-rise frames, and generally low-rise frames are more vulnerable to progressive collapse than high-rise frames. Furthermore, the possibility of progressive collapse under fire scenarios in the upper stories is more than that in the lower stories, especially for the top story. In this study, a new combined failure mechanism for global collapse of MRFs was identified. [ABSTRACT FROM AUTHOR]

Performance-based seismic codes ensure proper inelastic behaviour of reinforced concrete frames through capacity design, among others. This strategy relies not only on avoiding brittle failures and providing ductility to plastic hinges but also in their distribution within the frame aimed at a greater number of storeys involved in the eventual collapse mechanism. Although codes are generally in agreement to some basic principles in order to ensure capacity design, they show some discrepancies regarding the specific strategies. In this paper, capacity design provisions proposed by some European current codes—Eurocode 8, Italian NTC, and Spanish NCSE-02—are compared, and their effectiveness is discussed. The alternative formulation proposed by Italian code for "strong column–weak beam" turns out to be not suitable under specific circumstances, such as with large gravity loads or significant cantilever deformation in lower storeys. Regarding the value of axial load in columns to be considered for the calculation of shear and moment capacities, provisions in the three codes could eventually cause unconservative design for perimeter columns. The Spanish whole set of provisions is proved to not be effective due to their different fundamentals—they are based on overstrength instead of capacity. For all the three cases, some alternative procedures are suggested in this work. [ABSTRACT FROM AUTHOR]

A refined design procedure for the seismic retrofit of warehouses or, more generally, single-storey RC frames bounded by "drift-sensitive" masonry infills and glazed curtain walls, is proposed in this paper by means of hysteretic braces. The calculation method is based on displacement-based design (DBD) procedures in which both the as-built frame and the dissipative braces are modelled through simple linear equivalent SDOF systems arranged in parallel. In this regard, with respect to the provisions of the Italian Building Code, two refinements are introduced: (1) the definition of two performance targets tailored to the protection of glazed curtain walls (among most expensive non-structural components) and to ensure an acceptable level of damage level for masonry infills; and (2) the adoption of a more accurate formulation for the estimation of the equivalent viscous damping developed both by the main frame and the dissipative braces. The refined design method is applied to a case-study building and the achievement of the performance targets is verified through NLTH analyses. [ABSTRACT FROM AUTHOR]