Seismic Performance Evaluation Research Articles

Beam-column joint modeling effects on the seismic response of a non-ductile reinforced concrete building

Seismic performance evaluation of existing reinforced concrete buildings requires numerical approaches that reflect the damage modes that may arise from deficiencies in beam-column joints. In this study, the seismic performance of an existing reinforced concrete building with four stories was investigated by applying elastic and deformable beam-column joint models. The deformable beam-column joint model was verified using an exterior non-ductile beam-column joint test. The model included a rotational spring located at the joint with two connected nodes in a zero-length with rigid elements in the vicinity of frame elements. Moment- rotation relationships represent the joint behavior, and they were defined based on shear stresses and strains. After effective modeling of beam-column joints, it was aimed to obtain the cyclic behavior of the building model using non-linear time history analysis. For this purpose, scaled earthquake records were applied to the three-dimensional numerical model, and the results were compared in terms of inter-storey drift ratios, column and beam chord rotations, and base shear. It was determined that the exterior beam-column joints reached their strength and deformation capacity, while the beam and columns remained below their section deformation limits according to the Turkish Earthquake Code.

Data-driven prediction method for shear capacity of corroded rectangular reinforced concrete shear walls under varied failure modes

The physical and mechanical properties of rectangular reinforced concrete shear walls (RRCSW) will deteriorate over time due to acidic erosion, causing changes in damage characteristics and a reduction in shear capacity under seismic loading. The aim of this paper is to develop a failure mode-based prediction method for the shear capacity of corroded RRCSW, as the existing formulas for calculating shear strength become invalid in such scenarios. Initially, a total of 2403 RRCSW samples with various corrosion levels and main design parameters were generated and simulated using the authors' previous numerical method to obtain a comprehensive database of shear capacity. Subsequently, an efficient damage mode identification method for RRCSW was established using the Random Forest algorithm, and its accuracy and applicability in identifying damage modes of corroded RRCSW were verified. Finally, the existing calculation formulas for RRCSW in flexure-shear and shear failure modes were selected and modified to consider the corrosion effect based on the shear capacity database. The comparative analysis revealed that the proposed formulas provide accurate predictions of the shear capacity of corroded RRCSW, making the results of this study invaluable for seismic design of new structures and seismic performance evaluation of existing structures.

Seismic Performance Evaluation and Comparative Study of Reinforced Concrete Building on a Sloped Terrain with Regular Building by Considering the Effect of URM Infill Walls

This paper focuses on the seismic vulnerabilities of multi-storey buildings in hilly regions like Sikkim and Uttarakhand, where rapid construction is driven by population growth and tourism. The study particularly evaluates step-back buildings on hilly slopes, comparing their vulnerability to standard buildings on flat terrain. Using non-linear analysis to assess structural aspects like displacement and storey drift ratio, the research examines the performance of these buildings in both uphill and downhill orientations against typical three-storey and six-storey structures, respectively. The findings indicate that step-back buildings, especially those without infill walls, are more susceptible to seismic damage. For instance, on the uphill side, a step-back building shows a mean drift ratio 15.11% greater in the X direction and 4.57% greater in the Y direction compared to a three-storey regular building (3SR). This vulnerability is exacerbated when infill walls are absent, with mean drift ratios in step-back buildings being 74.75% and 33% higher in the X and Y directions, respectively. Moreover, at a seismic acceleration of 0.36 g, the mean displacement of a step-back building is 83% greater in the X direction and 51% greater in the Y direction than those with infill walls (SBIN), underscoring the significant role of infill walls in enhancing earthquake resilience. The study also highlights that short columns in step-back buildings are particularly prone to severe damage, especially just above the uppermost foundation level. While infill walls offer substantial mitigation of damage at the Design Basis Earthquake (DBE) level, at the Maximum Considered Earthquake (MCE) level, step-back buildings still endure severe damage compared to regular buildings with infill walls. Consequently, the research establishes that step-back buildings demonstrate greater vulnerability at DBE levels without infill walls and are more susceptible to damage than flat terrain buildings at MCE levels, emphasizing the need for careful design and reinforcement strategies in earthquake-prone hilly areas.

Seismic performance evaluation of reinforced concrete hilly buildings under sequence of earthquakes

SummaryThe present study investigates the effect of earthquake sequences on the response of reinforced concrete hilly buildings having typical configurations, that is, stepback and split‐foundation, with three different story ratios. A set of 30 as‐recorded mainshock‐aftershock sequence of earthquake ground motions is considered for this study. Mainshock acceleration time histories are scaled at two distinct intensity levels to obtain the mainshock‐damaged building. These mainshock‐damaged hilly buildings are then subjected to aftershocks. A comparative study is performed for various response quantities, such as peak interstory drift ratio, peak floor acceleration, and peak roof displacement of undamaged and mainshock‐damaged buildings under aftershocks. Further, fragility analysis is carried out to study the effect of aftershocks on undamaged and mainshock‐damaged hilly buildings. Subsequently, component‐wise seismic loss estimation due to damage in the non‐structural and structural components is performed. It is concluded from the study that the building components that contribute maximum to the expected repair cost ratio vary with respect to the intensity of the aftershocks. Also, the estimated seismic loss is higher in mainshock‐damaged split‐foundation buildings in comparison to stepback buildings.

Resilient joints with SMA bar-shear friction damper (SSFD) device in steel modern Chinese traditional-style buildings: Seismic performance evaluation and optimized design

To inherit and protect ancient Chinese architectural culture, modern building materials and techniques have been combined in the modern Chinese traditional-style building (MCTB) with similar exterior forms to ancient Chinese timber architecture. However, the typical joint in MCTB exhibits weak energy dissipation capacity and significant residual deformation under seismic actions, resulting in a problematic post-earthquake repair behavior. A semi-rigid friction-damped joint with resilient function has been proposed to improve the seismic performance and recoverability of MCTBs. Low-cyclic loading was conducted on four specimens of full scale. The results indicated that the yielding failure of four specimens primarily occurred in the vulnerable regions designed with replaceable angles. Compared with semi-rigid joints, the yield displacement, overall strength, initial stiffness, and cumulative energy dissipation of the specimen with the shape memory alloy (SMA) bar-shear friction damper device was significantly increased, and the residual deformation was significantly reduced, indicating that the device has a significant enhancement effect on the seismic and repairable performance of the structure. Based on the experimental results, a three-dimensional model was established using ABAQUS finite element software to optimize the design of joints and determine the optimal structural system that meets the requirements of MCTB.

Seismic Performance Evaluation of Reinforced Concrete Buildings Retrofitted with a New Concrete Filled Tube Composite Strengthening System

This study proposes a concrete-filled tube composite strengthening system (CCSS), which is a new concept that can improve and supplement the vulnerability of existing CFT seismic strengthening methods. The CCSS seismic reinforcement method is easy to construct and integrates with the existing frame and reinforcement. It is one of the seismic strengthening methods that allows the simple calculation of the required amount of seismic reinforcement and can efficiently increase the strength when applied to existing reinforced concrete (R/C) buildings with non-seismic details dominated by shear failure. To examine the seismic safety of the proposed CCSS, two framework specimens were prepared based on an existing R/C building with non-seismic details. A pseudo-dynamic test was conducted on the unreinforced framework specimen and the framework specimen reinforced with CCSS to verify the seismic strengthening effect of applying CCSS to the existing R/C framework, i.e., in terms of the load–displacement characteristics and seismic response control capability. Based on the pseudo-dynamic test results, restoration of the force characteristics was proposed for the nonlinear dynamic analysis of the building reinforced with CCSS. Nonlinear dynamic analysis was conducted based on the proposed restoration of the force characteristics, and the results were compared with the pseudo-dynamic test results. Finally, for the commercialization of CCSS, nonlinear dynamic analysis was conducted on the existing whole R/C building with non-seismic details that was reinforced with CCSS. The seismic strengthening effect was then verified by examining the seismic response load, displacement characteristics, and the degree of seismic damage to the members based on the ductility ratio before and after seismic strengthening. The study results show that under a design basis earthquake with a magnitude of 200 cm/s2, the unreinforced R/C building exhibits shear failure, and light seismic damage is expected on the CCSS-reinforced building.

Seismic Performance Evaluation and Analysis of Vertical Hydrogen Storage Vessels Based on Shaking Table Testing

In this study, the structural integrity of a system installed on protrusion concrete, considering the usability of a vertical hydrogen storage vessel, was verified. To achieve this, a site survey was conducted to select the target structure, and analytical validation was performed to design specimens for shaking table tests. Subsequently, dynamic behavior characteristics were analyzed using an artificial earthquake simulated according to the procedures outlined in ICC-ES AC 156, which is the seismic design criterion. As a result, it was observed that the seismic motion was amplified by approximately 10 times compared to the original load magnitude, based on the acceleration response of the test specimen. It is inferred that the seismic motion occurring during an earthquake could cause significant damage to both the internal and external aspects of the structure, depending on the structure’s form and the composition of materials. Through analytical verification and testing, it was revealed that the main structure of the test specimen and the anchor bolts for installation met the seismic performance criteria. However, the protrusion concrete area exhibited damage, indicating a structural vulnerability when subjected to external forces such as earthquakes. Consequently, on-site measures to address this structural risk need to be explored.

Seismic performance evaluation of fiber-reinforced prestressed concrete containments subject to earthquake ground motions

Given the unpredictability of the occurrence of the earthquake and other potential disasters into consideration, the nuclear power plant may be confronted with beyond design-basis earthquake load in the future. The containment structure may be severely damaged under such severe earthquake loading, increasing the risk of containment concrete cracking and potential radioactive materials leaking. Moreover, initial damage caused by the earthquake may significantly alter the pressure performance of the containment under follow-up internal pressure. To compromise the dangers of beyond design-basis earthquake to the containment, an alternative of replacing the conventional concrete with fiber-reinforced concrete (FRC) to upgrade the seismic resistance capacity of the containment is attempted and thoroughly researched. In this study, the influence of various fiber types such as rigid fiber and mixed fiber is regarded to constitute fiber-reinforced PCCVs. The physical properties of traditional and fiber-reinforced PCCVs under earthquake ground motions are scientifically compared and identified by using traditional and proposed evaluation indices. The results indicate that both the traditional evaluation index (i.e. top displacement, stress, strain) and the proposed damage index are greatly reduced by the practice of fiber strengthening under earthquake ground motions.

A Comprehensive Literature Review on the Seismic Performance Evaluation of Elevated Storage Reservoirs

A Comprehensive Literature Review on the Seismic Performance Evaluation of Elevated Storage Reservoirs

Seismic loss assessment of code-compliant moment-resisting RC buildings located on different soil conditions of Mexico City

This research aims to estimate the expected economic losses associated with the repair cost of a set of code-compliant moment-resisting reinforced concrete buildings located on different soil conditions in Mexico City. The loss assessment methodology is based on the second generation of the Performance-Based Earthquake Engineering (PBEE) framework, which quantifies the seismic performance of buildings in terms of metrics such as economic losses, downtime, and casualties, which are more meaningful to owners and stakeholders for the decision-making process. The methodology uses a probabilistic approach that takes into account uncertainties in seismic intensity, structural response, component damage, and consequence prediction. The seismic response of structures was calculated in terms of inter-story drifts and floor accelerations to assess the damage to their structural and non-structural components. In addition, taking into account the seismic hazard of the site, the expected annual losses (EAL) are calculated to provide insight into the seismic performance evaluation of structures with different characteristics in terms of the financial impact in seismic-prone regions like Mexico City.

Seismic design and performance evaluation of hybrid braced frames having buckling-restrained braces and self-centering viscous energy-dissipative braces

Hybrid braced frames (HBFs) emerge as an innovative seismic-resilient system, synergizing the strengths of buckling-restrained braces (BRBs) and self-centering viscous energy-dissipative braces (SCVDBs). This novel system has the potential to simultaneously manage three key seismic demand parameters: peak inter-story drift (PID), residual inter-story drift (RID), and peak absolute floor acceleration (PFA). Nevertheless, a dedicated seismic design method for HBFs is yet to be developed. This research proposes a performance-based seismic design (PBSD) method specifically tailored for HBFs. The method's core relies on energy decoupling in the HBFs using a proposed energy distribution factor (η). To validate the proposed design method, sets of 4-, 8-, and 12-story braced frames are designed using varied η. A comprehensive seismic performance evaluation is conducted, utilizing nonlinear static and nonlinear time-history analyses. The findings indicate that the HBFs, designed utilizing different values of η, consistently meet predefined performance objectives. Within the scope of this study, the η value of 0.5 is shown to be optimal, enhancing the structural resilience of HBFs against PIDs and PFAs while exhibiting excellent self-centering performance comparable to the self-centering viscous energy-dissipative braced frame (SCVDF). Additionally, the HBFs demonstrate superior control over PFA compared to pure buckling-restrained braced frame (BRBF) and SCVDF.

Seismic Performance Evaluation and Retrofit Strategy of Overhead Gas-Insulated Transmission Lines

The overhead gas-insulated transmission line (GIL) in ultra-high-voltage converter stations, distinct from traditional buried pipelines, demands a thorough investigation into its seismic behavior due to limitations in existing codes. A refined finite element model is established, considering internal structure, slip between various parts, and the relative displacement at the internal conductor joint. Seismic analysis reveals the vulnerability of the GIL at the corner of the pipeline height change, with two failure modes: housing strength failure and internal conductor displacement exceeding the limit. Furthermore, the acceleration amplification coefficient of the support generally exceeds 2.0. Two retrofit methods, namely increasing the fundamental frequency of all supports and fixing the connections between all supports and the housing, have been proposed. The results indicate the effectiveness of both methods in reducing the relative displacement. Fixing all the supports effectively reduces the stress, whereas the other one yields the opposite effect. The seismic performance of a GIL is determined not by the dynamic amplification of supports, but by the control of relative displacement between critical sections, specifically influenced by the angular deformation of the pipeline’s first-order translational vibration mode along the line direction. Seismic vulnerability analysis reveals a reduction of over 50% in the failure probability of the GIL after the retrofit compared to before the retrofit, with the PGA exceeding 0.4 g.

Evaluation of seismic performance of reinforced concrete columns retrofitted with steel links

The replaceable steel link (RSL) system enhances seismic performance by addressing early brace buckling found in conventional brace systems. This innovative system features a sliding slot, allowing for lateral steel link movement in response to column displacements, which effectively delays buckling. This study builds upon previous research introducing the RSL system and delves into the previously unexplored effect of the sliding slot length on the system's dynamic behavior. Experimental results showed that shorter sliding slots delayed the onset of shear cracks and concrete spalling, particularly when subjected to eccentric lateral loads. Retrofitted specimens exhibited a load capacity 1.5 times greater than their non-retrofitted specimen, irrespective of the slot length. The difference between the experimental and calculated shear strengths was a mere 4%, with a deviation from the FEMA 356 design criteria of approximately 12%. Therefore, the viability of using existing design criteria to predict the hysteretic behavior of retrofitted columns with the RSL system has been confirmed.

Optimizing net present values of risk avoidance for mountain railway alignments with seismic performance evaluation

AbstractRailway alignment optimization in earthquake‐prone mountainous (EPM) regions should quantify and trade off construction investments and seismic risks. Unfortunately, slight attention has been previously devoted to this trade‐off. To this end, based on the FEMA‐P58 methodology, a net present value (NPV) model of risk avoidance is presented and solved. In the model, alignment alternatives are first segmented into structural groups with different probabilistic seismic fragility curves, which are then used to generate structural repair cost and repair time curves. Afterward, a probabilistic seismic hazard curve is introduced to estimate the expected annual repair cost and time for computing railway direct and indirect seismic losses. Hence, the railway total annual loss caused by seismic activity can be obtained. Next, a benefit–cost analysis is performed to combine construction cost and seismic loss as the risk‐cost NPV. To optimize this objective function, a particle swarm algorithm is used as the basic approach. For implementing the probabilistic seismic performance analysis, a Monte Carlo simulation (MCS) is employed as the risk assessment module. Furthermore, due to the computationally intensive nature of MCS, a CPU‐based parallelization is embedded into the algorithm to expedite the search. Finally, the proposed model and method are applied to a representative real‐world railway case in an EPM region. Their effectiveness is discussed and verified in five experiments, including algorithm convergence analysis, alignment solution comparison, seismic risk interpretation, computational efficiency test, and a specific sensitivity analysis.

Macro-modelling method for the in-plane behaviour of the damped masonry infill wall in a frame structure

The damped masonry infill wall (DMIW) has been experimentally validated to have the ability to ameliorate the seismic problem caused by the diagonal action of the traditional masonry infill wall (TMIW). To lay the foundation for further structural analysis, a macro-modelling method for predicting the in-plane behaviour of the DMIW is developed. In this paper, the in-plane working mechanism is illustrated first and then a macro model of two diagonal elements which represent the behaviour of the damping layer joints (DLJs) is developed. In addition, the modelling method of the DLJ is developed and the method of identifying the parameters is considered. At last, experimental results are used to verify the macro-modelling method of the DMIW, followed by a case study on the seismic performance evaluation of the frame infilled by the DMIWs. The results indicate that the macro-modelling method has a clear physical meaning and is capable of predicting the in-plane cyclic behaviour of DMIW. The storey drifts and shear response of the frame infilled by the DMIW under the earthquake are almost the same as that of the bare frame, indicating that the effect of the DMIW on the bare frame is much less than that of the TMIW and further confirming that the DMIW is able to ameliorate the seismic problems caused by the diagonal action of the TMIW. In addition, the inter-storey drift is evenly distributed without a significant increase in the case where the DMIWs are not placed only in a particular storey, suggesting that the risk of developing the soft-storey failure mechanism of the frame can be significantly reduced even in the case where the arrangement of the TMIWs is irregular along the height.

Seismic performance of precast reinforced concrete shear wall structure connected with vertical indirect-lapping joints

The current vertical joints of precast reinforced concrete shear wall structures (PRCSWS) usually have long protruding vertical connection bars, precise positioning of vertical connection bars and high time cost due to grouting, hence reducing construction efficiency and quality. This paper proposes a new indirect-lapping joint for the vertical connection of PRCSWS, which could potentially address the difficulties of wall panel transportation and installation. To investigate the seismic performance of the PRCSWS vertically connected with the proposed joint, one cast-in-situ specimen and three precast specimens with different joint designs were fabricated and tested under a pseudo-static setup. The failure mode, hysteretic responses, ductility, stiffness degradation, energy dissipation, and crack opening of the wall-foundation joint were compared for the seismic performance evaluation. The impacts of joint designs on the seismic performance of the specimens were further discussed, focusing on the confinement reinforcements and connection cage distribution. Compared to the cast-in-situ specimen, the research showed that the precast specimens had the same failure modes and similar ultimate capacities of around 600.0 kN. The precast specimen with smaller indirect lapping spacing had similar plastic deformability and energy dissipation ability, shown by the 27% difference in displacement ductility coefficient and similar energy dissipation accumulation, respectively. Although the precast specimens exhibited a lower initial stiffness than the cast-in-situ specimen by 17%, all the specimens tended to have similar stiffness degradation, reflected by the nearly overlapped equivalent stiffness curves. With the same connection cage design, the additional spiral confinement reinforcements for vertical joints could improve plastic deformability shown by the improvement of displacement ductility coefficient by up to 11%, and the crack opening of the wall-foundation joint could be reduced by up to 30%. Increasing the indirect lapping spacing weakened the plastic deformability and energy dissipation ability, shown by the decline of displacement ductility coefficient and energy dissipation accumulation by up to 43% and by 14% respectively, and the crack opening of the wall-foundation joint increased by up to 67%. This research could potentially promote the application of the proposed vertical joint and address the construction difficulties of the current vertical joints of PRCSWS.

Cyclic load behaviour of reinforced concrete columns with SMA and ECC in the critical regions

Design techniques that can reduce the residual deformation are necessary to ensure that reinforced concrete (RC) structures function properly after earthquakes. The use of superelastic materials in the plastic hinge region permits the structure to undergo large displacements with less residual displacement upon load removal. The present study deals with the incorporation of two innovative materials, super-elastic shape memory alloy (SMA) and engineered cementitious composites (ECC), in the critical region or plastic hinge zone of the column. This numerical study focused on the seismic performance evaluation of full-scale RC circular cantilever columns reinforced with two types of nickel-based and two iron-based SMA and ECC in the critical region. The specimens were subjected to a reverse cyclic lateral loading with a constant axial load at the top. The performance of these hybrid columns was compared with those of conventional steel-reinforced columns and steel-reinforced columns with ECC in the critical region. The results of the study revealed that the columns reinforced with SMA and ECC in the critical region showed negligible residual displacement compared to the normal and ECC columns. The column reinforced with the FeNCATB SMA and ECC in the critical region showed better behaviour in terms of a higher load-carrying capacity and ultimate displacement/rotation under a higher drift ratio. From the longitudinal rebar strain profile, it is evident that this hybrid column specimen did not reach the elastic strain limit at a higher drift ratio than the other specimens.

Seismic performance assessment of hydraulic tunnels considering oblique incoming nonstationary stochastic SV waves based on the generalized PDEM

An important aspect of a seismic performance assessment framework is to adequately consider the stochastic nature of SGMs. This requires an appropriate method for synthesizing random SGMs, a crucial step in conducting structural response analysis. Additionally, affected by topographic and geological conditions, the incident angle of SGMs is also uncertain and random, which may induce unexpected damage to structures. To date, a framework is presented to assess the seismic performance of hydraulic tunnels under stochastic obliquely incident SV waves. The framework incorporates the spectral representation method of SGMs and obliquely incident SV waves into stochastic dynamic analysis. To create the appropriate PDFs and CDFs for numerous performance indices, the generalized PDEM and equivalent extreme-value event are introduced. Subsequently, stochastic dynamic analysis and seismic performance assessment of the hydraulic tunnel are performed. Finally, the disparity between the hydraulic tunnel fragility curves generated using conventional linear regression and generalized PDEM is examined. The difference between vertically incident and obliquely incident SV waves is discussed. The results indicated that (1) different performance indices exhibit great differences in the stochastic dynamic response of structures and the failure probability of seismic performance evaluation; (2) compared with the traditional linear regression method, the probability of damage of hydraulic tunnels under strong SGMs may be overestimated; and (3) nonstationary stochastic obliquely incident SV waves can cause more seismic demand than nonstationary stochastic vertically incident SV waves under low/medium earthquake intensity levels for hydraulic tunnel.

Evaluation of seismic performance of connected adjacent buildings using fragility curves

One of the effective methods to reduce the seismic response of the adjacent buildings is to connect these buildings by passive dampers. In this research, the seismic performance of this type of control system is evaluated using fragility curves. Furthermore, the parameters and arrangement of the connecting viscous dampers are investigated. For this purpose, two 8- and 12-story RC special moment-resisting frame buildings are connected by viscous dampers. After obtaining the appropriate parameters and arrangement of dampers, incremental dynamic analysis was performed under 22 far-field ground motions using OpenSees software. Assuming a log-normal distribution, the probability of exceedance of the performance level is calculated at each maximum ground acceleration value as a fragility curve. The fragility curves show that the connection of adjacent buildings by viscous dampers will improve the seismic performance of both connected buildings compared to the corresponding results of single uncontrolled buildings.

Concrete spalling damage detection and seismic performance evaluation for RC shear walls via 3D reconstruction technique and numerical model updating

Current three-dimensional (3D) reconstruction technique-assisted damage detection research focuses on identifying, classifying, and locating surface damage on concrete components, challenging to quantify the effect of the identified damage on structural capacity. This paper attempts to present a novel method based on the 3D reconstruction technique and numerical model updating to detect concrete spalling damage and evaluate the adverse effects of the detected damage on the seismic performance of reinforced concrete (RC) shear wall components. Through a new concept of information transition point matrix, the mapping relationship between the defective information concealed in the reconstructed 3D point cloud model of the inspected wall and the performance variation of its corresponding finite element model is established. Experimental results demonstrate that the newly proposed method can successfully locate the concrete spalling damage and quantify the bearing capacity variation of the inspected specimen, which has excellent potential for future applications in civil engineering.