Seismic Vulnerability Analysis Research Articles

Optimization of a novel lateral energy dissipation system for cable-stayed bridge with short piers based on seismic vulnerability analysis

Cable-stayed bridges with short piers are susceptible to becoming the structural weak link in seismic resistance during strong earthquakes. Traditional lateral restraint systems, such as fixed and sliding bearing systems, may impose substantial lateral forces and displacement demands, affecting the entire bridge's seismic safety. A butterfly-shaped steel plate damper has been developed and integrated into a lateral energy dissipation system along with elastoplastic cables to address this. Given the significant computational challenges and the complexity of identifying the optimal parameters for the energy dissipation system, this paper combines the probabilistic seismic demand model (PSDM) with the response surface method (RSM) to propose the seismic vulnerability fitting optimization method (SVFOM). Based on SVFOM, utilizing a central composite design (CCD), 17 analysis scenarios that account for the parameter variations of the lateral energy dissipation system are established. By developing response surface functions for bearing damage (ys) and pier damage (yp) through the seismic response fitting of the structure across all scenarios, we determined the optimal parameters for the lateral energy dissipation system to minimize damage to both bearings and piers. The finite element model validation analysis, which demonstrated significant reductions in pier displacement and the probability of bearing damage, confirms the effectiveness of the SVFOM. Optimized parameters showed that the new lateral energy dissipation system can significantly enhance the lateral seismic performance of cable-stayed bridges with short piers. Compared to scenarios without energy dissipation and with lateral sliding bearings, they demonstrated that this optimized system reduces the relative displacement of the piers and girders by 56 % and the probability of complete bearing failure by 87 % while maintaining pier damage within acceptable limits. This optimized system offers a valuable reference for the seismic design of similar bridge structures.

Analysis of the Seismic Vulnerability of a Masonry Pagoda Based on Increasing Dynamic Analysis

ABSTRACTFor the seismic vulnerability analysis method of masonry pagodas, the dynamic characteristic of the Bayun Pagoda in China was conducted by using environmental excitation technology. A numerical model of the masonry pagoda was established with the finite element software Abaqus. Ten seismic waves were selected as excitation signals to conduct incremental dynamic analysis (IDA) on the pagoda. The Sa(T1,5%) served as the seismic intensity indicator, whereas the damage factor (d) and relative stress () were employed as damage indicators for seismic vulnerability analysis of the pagoda. The failure probability of the structure reaching the limit state under different seismic intensities was determined. The results indicate that, comparing the IDA curves and seismic vulnerability curves under two different damage indicators, the Sa(T1,5%) range required for the IDA curves under the damage factor (d) is smaller than the relative stress (), with lower dispersion. Additionally, the failure probability of the pagoda reaching different limit states is higher under the damage factor (d). Considering the existing damage status of the masonry pagoda, the damage factor (d) is more reasonable as the damage indicator.

“Towards Earthquake Disaster Assessment Based On Seismic Vulnerability Analysis In Indore City”

“Towards Earthquake Disaster Assessment Based On Seismic Vulnerability Analysis In Indore City”

Comparative analysis of seismic response and vulnerability of laminated bamboo frame structure under near-field and far-field earthquake actions

The study offers an evaluation of seismic response and vulnerability for a five-story laminated bamboo frame structure, assessing the effectiveness of seismic intensity measures across various damage thresholds and the modeling uncertainties involved. A structural finite element model was developed in OpenSees software, utilizing the Pinching4 model to accurately represent the non-linear characteristics of T-shaped steel connections in beam-column joints. Two collections of earthquake records, one consisting of pulse-like near-field and the other of far-field events, were utilized to examine the structure's nonlinear behavior. Additionally, vulnerability curves for various damage states were generated using the multiple stripe analysis technique, applied to both ground motion datasets. The applicability of 24 seismic intensity measures was also analyzed across various damage limit states. The modeling uncertainty under different seismic actions was further estimated using a first-order second-moment method. Ultimately, the annual collapse probability of the structure are elucidated. Research indicates that due to the influence of joint stiffness, the overall structure demonstrates dynamic characteristics that are predominantly of the first mode shape. The spectral acceleration associated with the fundamental period achieves a reduced logarithmic standard deviation in the vulnerability analysis across various limit states. Other IMs considering higher mode effects or softening period actions no longer predominate. In most cases, the modeling uncertainty under far-field seismic action is higher than that under near-field, especially at the severe damage limit states by using an efficient intensity measure. The laminated bamboo frame structure faces a much higher collapse risk in near-field than in far-field conditions.

Seismic vulnerability analysis of hospitals and school buildings considering the Gaussian regression algorithm

This study combines the Gaussian regression algorithm to propose a nonlinear regression model that can be used to evaluate the seismic vulnerability of regional hospitals and school buildings. The failure features and disaster mechanisms of hospital and school buildings affected by the Jishishan (JSS) earthquake on December 18, 2023, and the Wenchuan (WC) earthquake on May 12, 2008, were reported. The samples of 252 damaged buildings (37 hospitals and 215 schools) in Dujiangyan city affected by the Wenchuan earthquake for which the author participated in the survey were collected and counted. Hospitals and school buildings were classified according to the types of reinforced concrete (RC) and masonry structures, and earthquake vulnerability probability matrices for hospital and school building clusters were established considering the actual failure probabilities. A total of 2103,213 acceleration records (from the Wenchuan earthquake) monitored by 12 real stations were selected. Using dynamic time history and response spectrum analysis methods, time history and spectrum curves were generated, considering the influence of different seismic directions. Using the developed Gaussian regression model, vulnerability comparison curves and parameter matrices considering multiple regression algorithms were generated. This paper considers the effects of the construction year and number of floors on the seismic vulnerability of hospital and school buildings. Seismic vulnerability curves and failure probability matrices were generated and established on the basis of actual structural failure probabilities. According to regression and vulnerability surface analysis, the evaluation results of the proposed model are highly consistent with actual field observations.

Seismic Vulnerability Analysis of Concrete-Filled Steel Tube Tied Arch Bridges Using Symmetrically Arranged High-Damping Rubber Bearings

Seismic Vulnerability Analysis of Concrete-Filled Steel Tube Tied Arch Bridges Using Symmetrically Arranged High-Damping Rubber Bearings

Selection of 110 kV Prefabricated Steel Substations Considering Seismic Vulnerability in China

Prefabricated modular substations are expected to become the mainstream construction type for substations in China. However, there is a lack of scientific basis for structural selection and seismic performance evaluation. Taking a 110 kV substation as an example, this study compares the construction cost of cast-in situ reinforced concrete (RC) substations and prefabricated steel (PS) ones. Two types of PS structures are considered: one with H-section steel columns and the other with box-section steel columns. A seismic vulnerability analysis is performed to compare the probability distribution of various damage states of substation building structures under different seismic damage levels. Results indicate that the construction cost of PS structures is approximately 27.9% higher than that of cast-in situ concrete. When using H-section steel columns, there is a significant difference in the flexural stiffness in two horizontal directions, resulting in reduced seismic performance in the weak-axis direction. The construction cost of using box-section steel columns is slightly higher than that of the H-section steel case, but its seismic performance is significantly improved. Although the probability of slight and moderate damage states for the box-section steel column scheme is generally higher than that of the cast-in situ RC scheme, the probability of collapse is reduced. Thus, box-section steel columns are recommended for prefabricated modular substation building structures.

Seismic vulnerability analysis of palace-style timber structures base on lumped mass model considering column rocking effect

To investigate the influence of joint reinforcement on the vulnerability of palace-style ancient timber structures, a spring-rigid rod analysis model was established, considering the mechanical behavior of tenon-mortise joints, column base joints, and bracket set joints. A lumped mass model was proposed using the centroid method and stiffness equivalent method and the accuracy of the simplified model is verified through shake table tests. Additionally, the influence of reinforcement on tenon-mortise joints and bracket set joint on the seismic displacement response was investigated, the optimal reinforcement range for joints was determined. Finally, incremental dynamic analysis was conducted on the model considering joint reinforcement, and the influence of optimal joint reinforcement on the seismic vulnerability of timber structures was researched. The study found that the optimal stiffness enhancement of column frame mortise-tenon joints range from 4 to 6 times and the stiffness of bracket set joints by 2.9 times. The probability of structural collapse of reinforced both mortise-tenon joints and bracket set joints was reduced by 15.56 %. However, individually reinforcing either tenon-mortise joints or bracket set joints only slightly decreases the probability of collapse.

Seismic Vulnerability Analysis of Multistorey Base Isolated RC Building

Seismic Vulnerability Analysis of Multistorey Base Isolated RC Building

Seismic vulnerability analysis of continuous beam bridge based on finite element Method

Seismic vulnerability analysis of continuous beam bridge based on finite element Method

Seismic vulnerability analysis of single-layer lattice shells with different rise-to-span ratios: Focusing on the selection of Sa(T1)-based intensity measures

This study conducted a detailed examination of seismic vulnerability across different limit states for Schwedler single-layer lattice shells with differing rise-to-span ratios. A comparative analysis of seismic intensity measures, particularly those centered around Sa(T1), was performed to evaluate their effectiveness in vulnerability analysis. To comprehensively address the inherent uncertainties in seismic actions, the study selected a dual set of ground motion scenarios, encompassing both far-field and pulse-type near-field events. A novel approach was employed, integrating a multi-indicator seismic performance assessment model based on the residual seismic safety framework, aiming to thoroughly quantify the cumulative seismic damage to lattice structures. Utilizing the multiple stripes analysis technique enabled the efficient generation of analytical results for vulnerability assessments at various damage thresholds. The findings revealed that lattice shells with larger rise-to-span ratios exhibit increased seismic robustness, notably with far-field seismic events causing more significant damage than their pulse-type near-field counterparts. Furthermore, the study determined that employing seismic intensity measures which consider the effects of higher modes significantly reduces variability in the vulnerability analysis when dealing with pulse-type near-field seismic activity. As a result, the use of the seismic intensity measure IM123 is recommended for assessing the vulnerability of lattice shells with varying rise-to-span ratios, under both far-field and near-field seismic conditions.

Probabilistic seismic hazard model and vulnerability analysis for typical regional structures

Probabilistic seismic hazard model and vulnerability analysis for typical regional structures

Seismic vulnerability analysis of a high‐rise steel frame structure equipped with novel displacement‐amplified viscoelastic dampers

SummaryThe energy dissipation capacity of conventional viscoelastic dampers (VEDs) cannot be fully exerted due to the relatively small inter‐story displacement of building structures. Thus, a novel VED with a displacement amplification mechanism based on the lever principle is developed in this study to achieve small displacement but high energy dissipation ability. First, the structural layout of an amplified viscoelastic damper (AVED) system is briefly introduced, and then the displacement amplification effect is described in detail. According to the working principle of the AVED and the relationship of force and geometric displacement in an actual frame structure, the restoring force theoretical formula of the corresponding amplified damper is derived. Based on the restoring force of the AVED and in combination with the secondary development function of the ABAQUS unit, a VUEL subroutine suitable for the explicit algorithm is programmed with the FORTRAN language. Then, the correctness of the subroutine is verified through a comparative analysis of the ABAQUS simulation and theoretically calculated results. Consequently, the vulnerability analysis of a high‐rise steel frame structure is conducted by using the incremental dynamic analysis (IDA) method, and the influence of the AVED on the seismic performance of the steel frame structure is quantitatively analyzed from the perspective of probability statistics. The analysis results show that compared with the VED structure, the failure probability of the AVED‐2 and AVED‐3 structures reaching the ultimate failure state at all levels is reduced by approximately 43% and 57%, respectively, and the collapse margin ratio (CMR) of structures under large earthquakes is increased by approximately 35% and 68%, respectively. This indicates that the AVED structures with displacement‐amplified dampers have a better effect on the seismic stability of tall steel frame structures under random seismic excitations. This study aims to provide comprehensive information for the seismic‐resistant design of tall buildings in earthquake‐prone regions.

Seismic numerical analysis of an Inca stone wall in Sacsayhuaman using rigid body dynamics within a finite element framework

The study and conservation of the stone heritage is a global concern, mainly when the buildings are in seismic zones. Stone structures can be very simple or considerably complex, depending on their style and form of construction. A clear example is the Inca architecture in Peru, which has different and complex typologies due to its cultural diversity. Inca structures of remarkable heritage value are in Cusco, an area of active cortical faults that might produce a seismic event at any time. The main objective of this research is to contribute to the knowledge of the seismic vulnerability analysis of Inca's stone walls by using the dynamics of rigid bodies (within the finite element method) to evaluate the possible out-of-plane failure mechanisms. This methodology allows for reducing the high number of degrees of freedom usually considered when modelling an entire irregular large stone wall by other approaches, such as continuum models. A wall section from the archaeological site of Sacsayhuaman (Cusco, Peru) is analysed as a case study. Each stone is discretised and modelled as a rigid body, and the interaction among blocks is evaluated within a finite element numerical framework. The structure's predominant frequencies are evaluated using updated methods such as white noise and sinusoidal signals. Then, a non-linear dynamic analysis of the studied wall is performed considering three Peruvian seismic records. The analyses show that the structure could suffer significant damage and endanger its structural stability for cortical earthquakes with a Peak Ground Acceleration (PGA) greater than 0.2 g. Considering the historical significance of these structures, the analysis of Inca stone walls' seismic safety accounts for potential residual movements between individual stones.

Seismic Vulnerability Analysis of Concrete-Filled Steel Tube Structure under Main–Aftershock Earthquake Sequences

Earthquakes are often followed by higher-intensity aftershocks, which tend to aggravate the accumulated and more severe damage to building structures. The seismic vulnerability of concrete-filled steel tube (CFST) structures under major aftershocks is more complex. In this paper, a CFST frame and a frame with buckling-restrained braces (BRBs) are studied, and the finite element analysis software Midas 2022 is used to analyze the seismic vulnerability of the two types of structures under main shock and main–aftershock. The results show that the structural vulnerability of the two structures is significantly higher under the main–aftershock sequences than under the main shock alone. Compared with the CFST structure, the structure with BRBs can effectively reduce the structural displacement and the hysteretic energy, decrease the plastic deformation risk of the structural components, and improve the seismic performance. The structure with BRBs can significantly reduce the probability of structural collapse under the main–aftershock sequence and can provide a reliable guarantee of the stability of the building.

Seismic performance and vulnerability analysis for bifurcated tunnels in soft soil

This paper investigates the seismic performance of complex comprehensive interchange underground structures. As an example, the seismic performance of Nanjing underground bifurcated tunnels constructed in soft soil is analyzed. A three-dimensional (3D) numerical finite element analysis model is established considering soil-tunnel interaction to analyze the seismic response characteristics and failure mechanism of the bifurcated tunnels. The results show that the tunnel damage degree is closely associated with the deformation response, and that the inter-story drift ratio of the lower layer is significantly greater than that of the upper layer. The pushover analysis method is used to obtain the seismic performance curve of the tunnel, and inter-story drift ratio limits are defined. The IDA procedure is then used to conduct multiple non-linear dynamic time history analyses based on the 3D finite element model, and IDA curve clusters are drawn with peak ground acceleration (PGA) as the earthquake intensity measures and the peak inter-story drift ratio as the damage measures of tunnels. The corresponding IDA percentiles lines are calculated, and the seismic fragility curves of the bifurcated tunnels are established. The post-earthquake functional failure probability of the bifurcated tunnels is obtained under different seismic fortification performance level.

Seismic Vulnerability Assessment in Tunnels: A Review

Vulnerability analysis is an important method for earthquake prevention and disaster reduction research in the field of tunnel engineering. Firstly, a detailed overview of the research history and current status of tunnel seismic vulnerability at home and abroad was provided; Secondly, the main methods for analyzing the seismic vulnerability of tunnels at home and abroad were summarized, and the practical applicability of various methods was summarized; Subsequently, the steps for evaluating the seismic vulnerability of tunnels were proposed, and three key contents in establishing theoretical vulnerability curves using numerical simulation as the main method were discussed: (1) Input parameter determination; (2) Classification of destructive states; (3) Calculation of relevant uncertainty parameters; Finally, point out some urgent problems and future research directions in this field. By summarizing the existing studies on the seismic vulnerability of tunnels at home and abroad, the results show that the seismic vulnerability analysis of tunnels can reflect the performance of tunnels under seismic loading by considering the relevant uncertainty factors, which is conducive to the future risk assessment and loss estimation, and is of great significance to the development of performance-based seismic design of tunnels.

Digital Twin and Asset Management for Italian highways decision support towards scheduled maintenance, repair and rehab

This paper describes Sina’s current inventory and inspection system (SIOS) development with BIM (Building Information Modelling) applications and BMS (Bridge Management System) strategies towards an Asset Management system implementation. Procedures and data flows using Sina databases SIOS (Sistema Ispettivo Opere Sina inventory and inspection data, seismic vulnerability analysis database, etc.) as inputs supporting BIM modelling are described. Starting from a first project, which is currently being applied to an entire highway agency and which also envisages a later integration of tunnels, a BIM modelling procedure was developed to reach information models for an “inspection” “BIM USE”. Such information models, populated with the information necessary for bridge management system processing, have been connected to Business Intelligence tools to create dashboards supporting decision-making criteria based on management and maintenance approaches (Bridge and Asset Management System). In addition, for Asset Management development, the approach of decision-making tools, integrated with a multi-level approach of Italian Guidelines For The Classification And Management Of Risk, The Assessment Of Safety And The Monitoring Of Existing Bridges, can convey information flows to support criteria planning to choose routine and extraordinary maintenance and restoring interventions. The project illustrated in this paper shows how integrating technologies, methodologies, experience and knowledge must be supported by consistent information management towards companies’ digital transformation and asset management development as a decision-making tool based on enabling technologies.

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Application of a Deep Learning Method to the Seismic Vulnerability Analysis of Cross-Fault Hydraulic Tunnels Based on MLE-IDA

Rapidly developed deep learning methods, widely used in various fields of civil engineering, have provided an efficient option to reduce the computational costs and improve the predictive capabilities. However, it should be acknowledged that the application of deep learning methods to develop prediction models that efficiently assess the nonlinear dynamic responses of cross-fault hydraulic tunnels (CFHTs) is lacking. Thus, the objective of this study is to construct a rational artificial neural network (ANN) prediction model to generate the mass data and fragility curves of CFHTs. Firstly, an analysis of 1080 complete nonlinear dynamic time histories via incremental dynamic analysis (IDA) is conducted to obtain the mass data of the drift ratio of the CFHT. Then, the hyper-parameters of the ANN model are discussed to determine the optimal parameters based on four examined approaches to improve the prediction capacity and accuracy. Meanwhile, the traditional probabilistic seismic demand models of the predicted values obtained by the ANN model and the numerical results are compared with the statistical parameters. Eventually, the maximum likelihood estimation couping IDA method is applied to assess the seismic safety of CFHTs under different damage states. The results show that two hidden layers, ten neurons, and the ReLU activation function for the ANN model with Bayesian optimization can improve the reliability and decrease the uncertainty in evaluating the structural performance. Moreover, the amplitude of the seismology features can be used as the neurons to build the input layers of the ANN model. It is found through vulnerability analysis that the traditional seismic fragility analysis method may overestimate the earthquake resistance capacity of CFHTs compared with maximum likelihood estimation. In practical engineering, ANN methods can be regarded as an alternative approach for the seismic design and performance improvement of CFHTs.