Seismic Performance Research Articles

Seismic Stability Analysis of Square and Rectangular Tunnels in Cohesive-Frictional Soils

Seismic Stability Analysis of Square and Rectangular Tunnels in Cohesive-Frictional Soils

Seismic Performance of Self-Centering Post-Tensioned Concrete Columns Reinforced with Steel–GFRP Bars and GFRP Spirals

Seismic Performance of Self-Centering Post-Tensioned Concrete Columns Reinforced with Steel–GFRP Bars and GFRP Spirals

Seismically induced deformations of layered slopes with non-unique and non-planar slip surfaces

Earthquake-induced deformation is prevalently used to evaluate the seismic performance of slopes, often assumed to occur along a predefined single slip surface. This paper presents a new limit equilibrium method combining with Newmark sliding block analysis for calculating the seismic displacement of layered slopes with non-unique and non-planar slip surfaces. The determination of the most and subsequent critical slip surfaces during the earthquake shaking is discussed with an emphasis on the coupling effects between the shallow and deep failures. The approach is validated by the results from numerical simulation and the shaking table model test of layered slopes. Comparison analyses are also performed for the predictions of seismic displacement from the developed and previous sliding-block models. It is found that the seismic sliding deformation at the first slip surface significantly affects the evolution and sliding deformation of the subsequent slip surface. For the considered example of layered slope, a second slip surface at deeper location passing through the slope toe is identified, and a coupled variation is observed for the sliding displacement along the two slip surfaces. These features are not well predicted from the available sliding-block models. The developed model can capture the interaction between the non-unique slip surfaces and the geometry effect of the non-planar slip surfaces.

Seismic response of RC short columns strengthened by high-strength stainless steel wire rope meshes reinforced ECC jacket

A novel strengthening scheme of high-strength stainless steel wire rope (HSSSWR) meshes reinforced engineering cementitious composite (ECC) jacket was used to strengthen the reinforced concrete (RC) short columns in this paper. The seismic performance of short columns after being strengthened was investigated, considering the changes in the strengthening scheme, and the spacing of lateral HSSSWRs. The failure mode, hysteresis behavior, envelope curve, ductility, energy dissipation, stiffness degradation, and strength degradation were introduced specifically based on the analysis of six full-scale short columns. The test results show a significant enhancement in the seismic performance of the strengthened short columns, especially in ductility and energy dissipation, which were increased by 49.4–98.4 %, and 149.3–713.2 %, respectively. The placement of HSSSWRs in ECC jacket proved to be effective in enhancing the strengthening effect of the jacket. A prediction model for the shear capacity of the strengthened columns was proposed using the Modified Compression Field Theory (MCFT), and the predicted results were in good agreement with the test results presented in this paper and in relative study.

Analyzing Seismic Performance of Optimized Base Isolation Systems with Soil–Structure Interaction: An Analytical and Numerical Approach

Analyzing Seismic Performance of Optimized Base Isolation Systems with Soil–Structure Interaction: An Analytical and Numerical Approach

An Investigation of Seismic Behaviour of Prestressed Concrete Frame Structures using Pushover Analysis

Abstract: The prestressed concrete system is a prominent material in civil engineering, with applications ranging from buildings, bridges, foundations, piling, silos, stadiums, roadways, and other infrastructure. However, this work is primarily concerned with its applicability to building frame constructions subjected to seismic loading. The prestressed concrete system for frame constructions not only reduces the amount of structural components, but it is also a cost-effective technology that provides outstanding strength and stiffness, as well as quick and simple site erection. Hence, we will be able to use these prestressed concrete components to their full capacity, unlocking engineering and social benefits that were previously impossible. Prestressed concrete designs, as opposed to reinforced concrete designs, can give structures with substantially longer spans, no cracks, or fewer cracks with tiny crack widths. Nonetheless, research on the seismic behaviour of prestressed concrete frame structures is relatively restricted, with the majority of studies focusing on reinforced concrete structures. Finally, the provisional versions of modern building codes such as ACI 318, GB50010, and EC2 do not provide thorough processes for seismic design of prestressed concrete structures. In this work, the seismic design and behaviour of prestressed concrete building frames are explored using the most recent design code. Three model-building codes will be investigated and compared, including ACI 318- 14, Eurocode 2004-2, and Chinese GB500010-2010. The 10-story prestressed concrete frame system is subjected to gravity and seismic loading, and the strong-column weak beam mechanism is archived to conform with the newly implemented building design code. To examine the behaviour of prestressed concrete frame structures, nonlinear static pushover analysis is used to capture the reaction under earthquake loading. The stiffness and strength needed will be designed in compliance with the three major building codes indicated. In addition, the finite element model will be created using CSI Sap200 to capture its actions.

Seismic behavior of CFDST frame with metallic dampers: Damage-controlled design and performance assessment

Current investigations on performance-based seismic design of structures generally employed story drift as performance objectives. However, the story drift could only partially reveal the global damage of a structure and not control the damage of important components. In order to control the damage of various components in a structure, this paper proposed a new damage-controlled seismic design method using the Park & Ang indexes of components. Firstly, the Park & Ang damage index was simplified as an equivalent ductility damage index for various components. The energy balance concept was used to observe the hysteretic energy demand which was subsequently distributed to all stories. Thus, the components of each story could be designed based on their damage indexes under design-based and maximum-considered earthquakes. Four concrete filled double skin tubular (CFDST) moment resisting frames equipped with metallic dampers with various layouts were designed based on the proposed design method. Time history analyses on these four structures were performed after validating the accuracy of nonlinear model by Opensees. Analysis results showed that the components in four structures exhibited expected damage states as illustrated by the design method. It also verified that proposed seismic design method was effective to control the damage of various components, which was beneficial for protecting the important components in a structure by setting low damage indexes for them. The seismic design method and analysis results also provided a reference for the design of moment resisting frame with energy devices.

Study on hysteresis performance of four-limb CFST latticed column-box girder joints based on GA-BP neural network

This study investigates the seismic performance and energy dissipation capacity of the concrete-filled steel tube (CFST) latticed column-box girder joints. A low-cycle reciprocating load test was carried out on the CFST latticed column-box girder joints with three different connection forms. Based on the test results, a genetic algorithm (GA) is developed in combination with the back propagation neural network (BPNN) model for prediction research. Using a training set of joints with single-limb diagonal and cross-diagonal braces (training set), the development of load-displacement hysteresis curves of joints with transverse diaphragm plate (test set) under low-cycle reciprocating loads is predicted. The test results are compared with those obtained from the traditional algorithms and finite element simulations. The results on the joint hysteresis performance show that all three types of joints have a good seismic performance and energy dissipation capacity. Compared with the traditional algorithms, the GA-BP model predicts more accurate results and is therefore used to predict the load-displacement hysteresis curves of CFST latticed column-box girder joints, which is shown to be convenient and feasible.

Behaviour of a Cold-Formed Steel Shear Wall with Centre-Corrugated Steel Sheathing under Cyclic Loading

A cold-formed steel shear wall with centre-corrugated steel sheathing (CCSS-CFS shear wall) was innovatively developed to meet the requirement of earthquake resistance for multi-rise CFS structures in regions at high seismic risk. This wall exhibits superior seismic performance in comparison with the conventional CFS shear wall. Five full-size specimens were tested under cyclic loading to evaluate their failure mode, shear strength, lateral stiffness, ductility, energy dissipation, as well as degradation of bearing capacity and stiffness. Additionally, the effects of CFS frame structure forms, screw spacing, and corrugated steel sheet thicknesses on the behaviour and failure mechanism of shear walls were analysed. The seismic performance objectives corresponding to intact, slight, moderate, and severe damage were also determined. The results revealed that the main failure modes of shear walls were plastic buckling of corrugated steel sheathing and local buckling of the end composite stud. Optimising configurations such as setting up stiffening plates on the end composite stud, installing transverse braces, and increasing screw spacing between composite studs and sheathing significantly improved their behaviour. The strength of corrugated steel sheathing after plastic buckling should be taken into consideration for the lateral design of the CCSS-CFS shear wall. A calculation method was also proposed in order to determine the elastic global buckling shear strength of the CCSS-CFS shear wall – which exhibited high accuracy. Finally, nominal shear strength, a resistance factor, and a safety factor were recommended.

Characteristics of Oil and Gas Distribution and Controlling Factors of Hydrocarbon Accumulations in the Eocene Pinghu Formation of the Xihu Depression, East China Sea

The Xihu Depression at the shelf of the East China Sea is a petroliferous basin with excellent exploration potential. The Eocene Pinghu Formation has become a recent oil and gas exploration target and as the critical hydrocarbon-bearing stratigraphic layer in the basin. However, studies specifically examining the characteristics of hydrocarbon distribution and the controlling factors of reservoirs in the Kongqueting area remain limited. The lack of in-depth hydrocarbon accumulation model research restricts subsequent exploration. In this paper, based on data from drilling, 3D seismic, well test, and geochemical analysis, we found that coal bed-related hydrocarbon source rocks were widely occurred in the Pinghu Formation in the Kongqueting area. The source rocks provide good hydrocarbon supply of near-source and distant-source to reservoir. The river sands were connected laterally and stacked vertically, forming a pattern characterized by ‘lateral succession and vertical superposition’ indicative of good quality of reservoir. During the deposition period of the Pinghu Formation, two large sets of regional cap rock (P3 and P7) were excellent sealing rock. The sand reservoir was interbedded with shale layers, forming a Mille-feuille type of reservoir-seal pair. Faults formed at the early stage of the formation of basin serve as conduits for hydrocarbon migration, governing both the spatial distribution of hydrocarbon-bearing strata and the types of hydrocarbon accumulations. These faults were instrumental in facilitating the formation of extensive oil and gas accumulations. This paper establishes a hydrocarbon accumulation model in the Kongqueting area, characterized as ‘dual hydrocarbon supply from source, upper oil, and lower gas, good reservoir-seal pair, hydrocarbon migration through fault conduit’.

Review Paper on Seismic Assessment and Analysis of Typical RCC Structure for Retrofitting

Review Paper on Seismic Assessment and Analysis of Typical RCC Structure for Retrofitting

Seismic Deformation Analysis of Precast Concrete Pipe Hybrid Based on 3D LiDAR and Unmanned Aerial Vehicle Photogrammetry

Seismic Deformation Analysis of Precast Concrete Pipe Hybrid Based on 3D LiDAR and Unmanned Aerial Vehicle Photogrammetry

Experimental study on seismic behavior of reinforced concrete exterior beam-column joints under varying axial load

The majority of low-cycle loading tests on reinforced concrete (RC) beam-column joints were currently conducted under constant axial loads. During earthquake shaking, the axial load on the joints fluctuates due to the overturning moment and vertical ground vibration. Particularly in exterior beam-column joints, where beam shear occurs on only one side, the range of axial load variation is significantly larger. To elucidate the impact of varying axial loads on the seismic performance of exterior beam-column joints, low-cycle loading tests were conducted on four groups of full-size beam-column subassemblage specimens. Two identical specimens from each group underwent low-cycle loading tests with constant and varying axial loads, respectively. Based on the experimental findings, this paper examines the differences in cyclic behaviors among comparison specimens, focusing on damage characteristics, joint shear strength, stiffness degradation, displacement ductility, and longitudinal bar slip. The study suggests that compared to specimens subjected to constant axial loads, the comparison specimens exhibit variations in load-carrying capacity corresponding to the fluctuations in axial load. Furthermore, varying axial loads accelerate post-peak stiffness and strength degradation, leading to reduced ductility. Additionally, specimens in one of the comparison groups exhibited different failure models when subjected to varying axial loads and constant axial loads, specifically beam failure and joint failure, respectively. Numerical simulations of the corresponding beam-column subassemblages were conducted on the Opensees platform to elucidate how the two axial loading methods affect the transformation of failure modes. A subsequent parametric study focusing on the axial compression ratio was performed to further explore the impact of varying axial loads on the seismic behavior of beam-column joints.

Influence of Ground Motion Non-Gaussianity on Seismic Performance of Buildings

Influence of Ground Motion Non-Gaussianity on Seismic Performance of Buildings

Seismic Analysis of Re-Entrant Corner Plan Irregular Buildings with Roof Openings Using STAAD Pro: A Case Study for Zone III Earthquake Intensity

Seismic Analysis of Re-Entrant Corner Plan Irregular Buildings with Roof Openings Using STAAD Pro: A Case Study for Zone III Earthquake Intensity

Development of the compound intensity measure and seismic performance assessment for aqueduct structures considering fluid-structure interaction

The primary motivation of this investigation is to develop the compound ground motion intensity measure (IM) for the seismic performance assessment of aqueduct structures. To achieve this goal, taking the typical aqueduct structure in Southwestern China as a case study, a three-dimensional finite element model of aqueduct-water-foundation fully coupling system is established. Moreover, for the seismic hazard, a total of 300 as-recorded ground motions based on the design response spectrum are selected from PEER-NGA strong ground motion database, including near-field non-pulse (NFNP), near-field pulse-type (NFP) and far-field (FF). Then, the nonlinear correlation between single IMs is considered by Copula function, the compound IM is proposed that can comprehensively characterize the seismic performance of the aqueduct structure. Based on evaluation criteria, the applicability of the proposed compound IM is compared and verified. Finally, the conditional probability function and the unconditional probabilistic seismic risk analysis is employed to evaluate the seismic performance of aqueduct structures. It can be concluded that the compound IM considers the acceleration, velocity and displacement factors, which improves the correlation, efficiency and proficiency of probabilistic seismic demand analysis. Furthermore, the compound IM can help to improve the accuracy of the structural seismic performance assessment and reduce the uncertainty of structural response estimation. In summary, the findings of this study highlight the significance of proposing the compound IM and developing fragility curves when evaluating the seismic performance of aqueduct structures.

Structural Damage Model of Steel Structure Connections with Initial Defects: A Review

As the application of steel structures in construction continues to grow, research into their seismic performance is becoming increasingly important. This paper focuses on steel structure connections, specifically those between components with varying profiles such as H-profiles, box-profiles, and L-profiles. Additionally, it encompasses three core areas: seismic performance (bearing capacity, ductility, stiffness), initial defects (initial cracks, residual stresses, manufacturing imperfections), and damage models (weld fractures, bolt failures, plate buckling). In addition, this paper employs experimental testing and finite element, with a focus on conducting parametric analyses for the connections. Based on the primary findings, the presence of initial defects such as cracks, residual stresses, and manufacturing imperfections can lead to premature failure, concentrating damage near welds and exacerbating stress concentrations. This adversely affects factors like fatigue strength, fracture toughness, and buckling strength, ultimately reducing the seismic performance of the connections. Moreover, factors like bolt over-tensioning, geometric deviations in plate components, and corrosion can further impact bearing capacity, fatigue performance, and ductility. Crucially, these initial defects not only compromise the seismic resistance of structures but also increase the risk of structural failure. However, majority of existing research has focused on monotonic and cyclic loading studies, with limited exploration of connections under seismic conditions. Acknowledging this gap, this paper outlines a future research agenda aimed at refining the design of steel structure connections. This initiative seeks to mitigate potential adverse consequences stemming from formidable seismic events, thereby enhancing the overall resilience of these crucial connections.

Seismic Performance Analysis of PEC Structures

Partially-Encased Composite Steel and Concrete Members (PEC members for short) consists of H-shaped cross-section of the main steel and concrete filling between the flange and the web, compared with the pure steel structure, the PEC structure has the advantages of high stiffness, high bearing capacity, good fire resistance and so on. The arrival of an earthquake may cause damage to building structures. The use of PEC structures can effectively improve their bearing capacity and seismic performance, and the method of post earthquake repair is relatively easier and more economical. In recent years, PEC components have been gradually popularized and applied in building structures.

Seismic Risk Assessment in School Buildings: A Comparative Study of Two Assessment Methods

Seismic risk assessment in school buildings is critical for ensuring the safety and resilience of educational institutions against seismic events. This paper presents a new seismic risk methodology named MM Risk and comparative study with Adriseismic methodology used for seismic risk assessment. The study aims to provide insights into the effectiveness and reliability of these methods in evaluating the seismic vulnerability of school buildings. Through a comprehensive review of the existing literature and application on a dataset of 213 schools (367 buildings), this paper evaluates the strengths and limitations of each method in terms of accuracy, complexity, and practical applicability. The results show that by integrating the approach of Adriseismic methodology and incorporating extensions related to irregularities, the social risk component (number of users), and the ability to assess different types of structures, a comprehensive and tailored methodology for assessing seismic risk can be developed. This is important since these factors are strongly influencing the seismic risk of schools as connected systems. Furthermore, this paper explores the implications of these findings for improving seismic risk mitigation strategies in school buildings. MM Risk methodology places over 70% of school buildings in the medium seismic risk category and 27% in the high seismic risk category. On the other hand, the Adriseismic methodology is more stringent, classifying 60% of school buildings into high and very-high risk categories. This disparity undoubtedly influences the prioritization list for seismic risk mitigation measures. However, definitely the comparative analysis presented in this paper offers valuable guidance for engineers, policymakers, and stakeholders involved in the seismic retrofitting and design of school buildings, ultimately contributing to the enhancement of seismic resilience in educational infrastructure.

Sequence Deep Learning for Seismic Ground Response Modeling: 1D-CNN, LSTM, and Transformer Approach

Accurate seismic ground response analysis is crucial for the design and safety of civil infrastructure and establishing effective mitigation measures against seismic risks and hazards. This is a complex process due to the nonlinear soil properties and complicated underground geometries. As a simplified approach, the one-dimensional wave propagation model, which assumes that seismic waves travel vertically through a horizontally layered medium, is widely adopted for its reasonable performance in many practical applications. This study explores the potential of sequence deep learning models, specifically 1D convolutional neural networks (1D-CNNs), long short-term memory (LSTM) networks, and transformers, as an alternative for seismic ground response modeling. Utilizing ground motion data from the Kiban Kyoshin Network (KiK-net), we train these models to predict ground surface acceleration response spectra based on bedrock motions. The performance of the data-driven models is compared with the conventional equivalent-linear analysis model, SHAKE2000. The results demonstrate that the deep learning models outperform the physics-based model across various sites, with the transformer model exhibiting the smallest average prediction error due to its ability to capture long-range dependencies. The 1D-CNN model also shows a promising performance, albeit with occasional higher errors than the other models. All the data-driven models exhibit efficient computation times of less than 0.4 s for estimation. These findings highlight the potential of sequence deep learning approaches for seismic ground response modeling.