Seismic Damage Index Research Articles

The interpretation of cumulative damage from the building response observed in Mexico City during the 19 September 2017 earthquake

This work evaluates the damage to and collapse of a set of buildings in the September 2017 earthquake in Mexico City; these buildings were also subjected to the September 1985 Mexico City earthquake. These buildings were located in the area of the highest rate of damage or collapse in 1985, but buildings exhibiting significant damage or collapse in 2017 did not possess any retrofitting. The spectral demands for these buildings, based on typical records registered in the earthquakes of 1985 and 2017, were not much different, suggesting the need to explain why the buildings that collapsed suffered severe damage in 2017 but not in 1985. This building behavior was analyzed using a seismic damage index Id, previously proposed by the author, which considers the effect of cumulative damage. The results indicated that the observed damage to and collapse of these buildings in the September 2017 earthquake can be explained by the effect of cumulative seismic damage. Recommendations are given for possible improvements to the seismic building codes in Mexico.

Seismic behaviour and strength prediction of corroded RC columns subjected to cyclic loading

In this paper, the performance degradation of reinforced-concrete (RC) columns with corroded longitudinal steel bars was experimentally investigated. Ten large-scale RC column specimens were constructed, and the longitudinal steel bars were corroded, to simulate the real severe environmental condition that concrete structures may encounter during their long-term service life, using a hybrid method. All specimens were tested under lateral cyclic loadings up to failure with the aim of revealing the effects of rebar corrosion level and axial compression ratio on the seismic behaviour of corroded RC columns. Test results indicate that an increase in the rebar corrosion level and axial compression ratio causes a marked degradation in the seismic performance of corroded RC columns, especially a reduction in the strength, ductility and energy dissipation capacity. To study the effect of the rebar corrosion level, the seismic damage indices of the corroded RC columns were also assessed using the damage model proposed by Park–Ang. In addition, a strength prediction method for corroded RC columns was proposed based on the modified compression field theory coupled with the conventional sectional analysis method. The proposed prediction method was then verified with the experimental results.

A Seismic Hazard Prediction System for Urban Buildings Based on Time-History Analysis

Seismic hazard prediction is essential for earthquake preparation in urban areas. Prediction methods based on refined the finite element method (FEM) models and time-history analysis require higher calculation, which is hard to apply universally. In this paper, by applying two simplified models and time-history analysis, the authors were able to develop a refined seismic hazard prediction system for urban buildings using MATLAB and OpenSees. The system is modular in design with a unified data interface to transfer data, where only the macro parameters of buildings are required to complete the computation work. Taking the campus of Tongji University as a test area, the system was applied to predict seismic hazard and compare it with the results of the vulnerability method by applying the seismic damage index to verify its reliability. The results show that the system can meet the needs of accuracy, efficiency, and visualization of seismic hazard prediction in urban areas.

Enhancing flexural capacity of RC columns through near surface mounted SMA and CFRP bars

This study explores the flexural behavior of reinforced concrete (RC) columns strengthened with near surface mounted (NSM) shape memory alloy (SMA) bars or carbon fiber reinforced polymer (CFRP) bars. Seven RC column specimens were designed and fabricated to study the influence of different variables on the flexural response of the strengthened columns. These parameters include type of NSM reinforcement (SMA bars or CFRP bars), ratio of NSM reinforcement, and effect of CFRP jacketing. The columns were tested under cyclic lateral loading with constant axial force. The flexural behavior of each specimen was examined in terms of peak load, failure load, drift ratios, displacement ductility, stiffness degradation, energy dissipation, and seismic damage index. The experimental results indicate that strengthening of RC columns with NSM SMA or CFRP bars improves the flexural behavior of the columns through increasing the lateral load capacity, reducing the stiffness degradation and increasing the cumulative energy absorption up to failure. Further enhancement in the lateral response of RC columns was obtained by combining NSM bars and CFRP jacketing as the later provides an additional confinement to the critical sections of the test specimens.

Seismic vulnerability comparison between rural Weinan and other rural areas in Western China

Generally, the anti-seismic capacity of rural buildings in China is poor due to their irregular design and construction. On the basis of historical destructive earthquake records, corresponding earthquake loss evaluation compilations (1993–2016), field investigations, and remote sensing interpretation, building structures in rural Weinan are classified into two types and analyzed to acquire the seismic vulnerability matrices by employing the fitting method of beta probability density function (BPDF). Results show that BPDF can well reveal the probability density distribution of seismic damage index, and also the damage ratio obtained agrees well with the description of damage degrees in Chinese macroseismic intensity scale.The vulnerability indexes in rural areas of Yunnan, Sichuan, Qinghai provinces and in Weinan City (Shaanxi province) were calculated and a comparison of aseismic ability was made. Results show that, among the rural areas in Western China, the aseismic abilities of traditional buildings in rural Weinan are the lowest while those of masonry buildings are highest. Moreover, potential losses in rural Weinan are estimated on the assumption that a scenario earthquake with a magnitude Ms 6¾ hit Weinan City, proposed by the UK-China Collaboration programme ‘‘Increasing Resilience to Natural Hazards in Earthquake-Prone regions in China”. It was found that the damage ratios obtained captured the distribution of the aseismic abilities of the rural buildings and therefore improved the accuracy of the loss assessment, which provides scientific basis for the scenario narratives. What we discovered in this paper is also helpful in future earthquake damage prediction and enhancement of public awareness on earthquake resistance.

Comparative evaluation of MFP and RBF neural networks’ ability for instant estimation of r/c buildings’ seismic damage level

The problem of the seismic damage prediction of reinforced concrete (r/c) buildings utilizing two types of Artificial Neural Networks (ANN) is investigated in the present paper. More specifically, the problem is formulated and solved in terms of the Function Approximation problem as well as of the Pattern Recognition problem using Multilayer Feedforward Perceptron Networks (MFP) and Radial-Basis Function (RBF) networks. The required training data-sets are created by means of Nonlinear Time History Analyses of 90 r/c buildings which are subjected to 65 earthquakes. The selected buildings differ in total height, in structural system, in structural eccentricity as well as the existence or not of masonry infills. The seismic damage index which is used to describe the seismic damage state is the Maximum Interstorey Drift Ratio. The influence of the parameters which are used for the configuration and the training of MFP and RBF networks on the reliability of their predictions is also investigated. The generalization ability of the best configured ANNs is examined by means of two categories of seismic scenarios. The most significant conclusion that turned out is that the trained ANNs can reliably and rapidly classify the r/c buildings into pre-defined damage classes provided they are appropriately configured.

INFLUENCE OF STRAINING BEAMS ON THE SEISMIC FRAGILITY OF DOUBLE-COLUMN BRIDGE PIERS

The piers of girder bridges have a very important role on the safety of the structural system to earthquakes. This paper addresses the seismic fragility of double-column (DC) bridge piers by focusing on the influence of the straining beams and the direction of seismic waves. The seismic capacity of eight DC piers with different number and position of straining beams is first studied by pushover analyses. These results are used to derive empirical formulas for the seismic capacity of general DC piers and to define damage indices for prescriptive damage states. Finite element models of typical girder bridges with the different piers are carried out next to assess the seismic demand of these piers and to generate fragility curves by comparing their seismic demand and damage indices at the defined damage states. Results indicate that: (1) DC piers are more vulnerable when subjected to longitudinal ground motions compared with the case of transverse inputs; (2) the damage probability of the piers for transverse seismic inputs decreases with the increasing relative height of the straining beams; and (3) DC piers with two straining beams have enhanced performance in the transverse direction compared with those with a single straining beam.

Hybrid backpropagation neural network-particle swarm optimization for seismic damage building prediction

The evaluation of the vulnerability of buildings to earthquakes is of prime importance to ensure a good plan can be generated for the disaster preparedness to civilians. Most of the attempts are directed in calculating the damage index of buildings to determine and predict the vulnerability to certain scales of earthquakes. Most of the solutions used are traditional methods which are time consuming and complex. Some of initiatives have proven that the artificial neural network methods have the potential in solving earthquakes prediction problems. However, these methods have limitations in terms of suffering from local optima, premature convergence and overfitting. To overcome this challenging issue, this paper introduces a new solution to the prediction on the seismic damage index of buildings with the application of hybrid back propagation neural network and particle swarm optimization (BPNN-PSO) method. The prediction was based on damage indices of 35 buildings around Malaysia. The BPNN-PSO demonstrated a better result of 89% accuracy compared to the traditional backpropagation neural network with only 84%. The capability of PSO supports fast convergence method has shown good effort to improve the processing time and accuracy of the results.

Hysteretic Behavior of Steel Reinforced Concrete Columns Based on Damage Analysis

With the aim to model the seismic behavior of steel reinforced concrete (SRC) frame columns, in this research, hysteresis and skeleton curves were obtained based on the damage test results of SRC frame columns under low cyclic repeat loading and the hysteretic behavior of the frame columns was further analyzed. Then, the skeleton curve and hysteresis loops were further simplified. The simplified skeleton curve model was obtained through the corresponding feature points obtained by mechanical and regression analysis. The nonlinear combination seismic damage index, which was developed by the test results and can well reflect the effect of the loading path and the number of loading cycle of SRC frame columns, was used to establish the cyclic degradation index. The strength and stiffness degradation rule of the SRC frame columns was analyzed further by considering the effect of the accumulated damage caused by an earthquake. Finally, the hysteresis model of the SRC frame columns was established, and the specific hysteresis rules were given. The validity of the developed hysteresis model was verified by e comparison between the calculated results and the test results. The results showed that the model could describe the hysteresis characteristics of the SRC frame columns under cyclic loading and provide guidance for the elastoplastic time-history analysis of these structures.

Probabilistic seismic demand and capacity models and fragility curves for reticulated structures under far-field ground motions

This paper aims to develop probabilistic seismic demand models (PSDMs), probabilistic seismic capacity models (PSCMs) and fragility curves for the widely-constructed reticulated structures using far-field earthquake records. The ground motion variability and prevailing uncertainties in structural design and modeling are considered, via performing incremental dynamic analyses (IDAs) on sample models of eighteen generic reticulated shells under forty far-field three-dimensional ground motions. A seismic energy demand-based damage index (DIE) is introduced and then employed together with the peak ground acceleration (PGA), to develop PSDMs and PSCMs for the reticulated shells considered, on the basis of statistical evaluation of the IDA results. The effects of two key structural design parameters, i.e., rise-to-span (or -width) ratio and roof load, on the PSDMs are investigated, and the normalized values for the PSCMs are also recommended. Fragility curves are derived and plotted to examine the difference among reticulated shells with different design parameters. It is concluded that DIE has strong correlation with PGA, and is more appropriate for developing PSDMs for the reticulated shells; and it also suggests that the reticulated shells with bigger rise-to-span (or -width) ratios or larger roof loads are more likely to damage or collapse during earthquakes. These results and conclusions will facilitate the performance-based seismic design and seismic vulnerability assessment of reticulated structures.

Correlation of Ground Motion Intensity Measures and Seismic Damage Indices of Masonry-Infilled Steel Frames

The main aim of this study was to analyze the response of structures with masonry infill walls to the intensity measure (IMs) parameters. Hence, two sets of earthquake ground motions, ordinary seismic records (OSR) and pulse-like seismic records (PLSR), were used for the nonlinear dynamic analysis of multi-story steel structures with masonry infill walls. Seismic performance was evaluated using the general indicators of damage (modified Park–Ang index), maximum inter-story drift ratio (MIDR) and roof drift ratio (RDR). The correlation between the multiple IM parameters with and without pulse-like ground motion and the damage indices of steel moment frames with and without masonry-infilled walls was determined using the Spearman correlation coefficient. Moreover, the correlation between the damage criteria and IMs was investigated. The results revealed that the spectral acceleration and velocity at the primary period of the structure and seismic parameters which are related to velocity have a strong relationship with MIDR and RDR. However, the correlations for PLSR and OSR were differed. The results indicated that the analysis of IMs with ground motion could help predict the parameters for building failure in various systems. The presence of masonry-infilled walls has changed the correlation coefficient for a fully infilled frame when compared with a bare frame.

Seismic Damage Behavior of Aeolian Sand Concrete Columns with an Inner Square Steel Tube

In order to promote the application of aeolian sand in steel‐concrete composite structures, the aeolian sand concrete columns with an inner square steel tube is proposed in this paper. This kind of column is composed of aeolian sand concrete, reinforcing steel, and an inner square steel tube. The seismic damage behavior of the column was studied through cyclic loading test and damage analysis on seven specimens with different structural forms. The seismic damage indices of the specimens in this study include the failure mode, bearing capacity, ductility, stiffness, hysteresis behavior, and energy dissipation. Then, a damage model of this kind of column is proposed. The study results show that installing an inner square steel tube can significantly improve the seismic damage behavior of aeolian sand concrete columns. This mode of construction can be used to enhance the replacement percentage of aeolian sand. In addition, the damage model proposed in this paper agrees well with the experimental results and can be used to evaluate the damage degree of the aeolian sand concrete columns with an inner square steel tube.

Damage index analysis of prefabricated segmental bridge columns under cyclic loading

Abstract The damage index is usually applied to evaluate the damage states of bridge structures, which is the basis of structural fragility study. The present study investigates the seismic damage index of the prefabricated segmental bridge columns (PSBC) under cyclic loading by theoretical and numerical analysis. Based on the previous pseudo-static experiments, different damage states characteristics of the monolithic cast-in-place bridge columns (MCBC) and the PSBC are discussed and analyzed to propose the limit-state capacities for each damage state of the PSBC. The limit-state capacities include four parameters: compressive strain of concrete, the tensile strain of steel, the prestress level and the residual displacement. Two finite element models of the PSBC are developed by OpenSees to carry on numerical analysis. Using the numerical results, the damage indexes for the PSBCs are obtained based on the limit-state capacities obtained above. The results indicate that the numerical results show good agreement with the experimental results of the bridge columns. The damage index formula of the PSBC, derived in this study, is reasonable and can be further applied. The maximum error between the proposed damage index and that obtained in the verified case is 20.3%. The proposed method in this paper for developing the damage index of the PSBC can be used in the seismic vulnerability analysis assessment of the bridge structures with prefabricated segmental columns.

A correction method for objective seismic damage index of reinforced concrete columns

In this paper, the sensitivity of a plastic-damage-based structural damage index on mesh density is studied. Multiple finite element meshes with increasing density are used to investigate their effect on the damage index values calculated from nonlinear finite element simulations for a reinforced concrete column subjected to cyclic loading. With the simulation results, this paper suggests a correction method for the objective damage index based on nonlinear regression of volumetric tensile damage ratio data. The modified damage index values are presented in the quasi-static cyclic simulation to show the efficacy of the suggested correction method.

Damage Index for Different Structural Systems Subjected to Recorded Earthquake Ground Motions

This study quantifies the damage index previously proposed by the writer ( Rodriguez 2015 ) for different structural systems subjected to a set of earthquake ground motions recorded during 12 strong earthquakes in different countries. Damage spectra were also computed using this seismic damage index. This study revisits the previously proposed index and shows that this index can also be interpreted as a ratio of velocities in the structural system responding to the earthquake demand. In addition, this study gives a more general damage analysis interpretation than that of the previous study since damage spectra were computed to assess the damage potential of a given recorded earthquake ground motion for different types of earthquake-resisting systems. The results from the damage analysis are consistent with the findings from previous research: most structural wall buildings show satisfactory earthquake performance, whereas frame buildings frequently show severe damage and collapse.

Assessment of Seismic Damage Indices for RC Frame Building Using Non Linear Static Pushover Analysis

Assessment of Seismic Damage Indices for RC Frame Building Using Non Linear Static Pushover Analysis

Optimization of infill panel for seismic response of multi-story RC frame buildings utilizing multi criteria optimization technique

For seismic excitations with different intensities, the performance-based seismic design concept is essential for designers to accurately control the level of damage and keep overall seismic response of buildings within acceptable limits. In order to investigate the feasible solution-set for many real large-scale buildings such as tall buildings and large-span bridges subjected to dynamic loads, an experimental test of such a large-scale physical model is necessary but it is too expensive to conduct such a test for only one prototype. Recently, optimization of the performance-based seismic design for the large-scale structures such as multi-story RC frames is considered by engineers to obtain the optimal and rapid solution. This paper presents a technique for multi criteria analysis, which involves an inelastic analysis and dynamic response of the infill RC frames in the optimization process. The optimal geometric and mechanical properties of infill panel were investigated to improve the seismic performance of a 12-story RC infill frame. As a typical construction process in Egypt, the 12-story RC frame is introduced as a real-life large-scale case study. The parameter space investigation method was adopted along with use of IDARC-2D software for inelastic damage analysis and the visual basic programing language to establish the feasible and Pareto solution-set for the studied frames. The successful integration of inelastic damage analysis and the parameter space investigation method shows great potential to utilize the multi-criteria optimization method for large-scale structures to obtain the Pareto optimal-set in the future. The study concludes that the optimization of geometric and mechanical properties of infill panel is essential and significantly improves the seismic response and damage index of the infill RC frames.

Seismic Damage Index Proposal and Damage Assessment for Cable-Stayed Bridge

Seismic Damage Index Proposal and Damage Assessment for Cable-Stayed Bridge

Seismic Damage Index Based on Fractal Dimension of Cracking on Thin Reinforced Concrete Walls

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Damage‐based seismic planar pounding analysis of adjacent symmetric buildings considering inelastic structure–soil–structure interaction

SummaryIn cities and urban areas, building structures located at close proximities inevitably interact under dynamic loading by direct pounding and indirectly through the underlying soil. Majority of the previous adjacent building pounding studies that have taken the structure–soil–structure interaction (SSSI) problem into account have used simple lumped mass–spring–dashpot models under plane strain conditions. In this research, the problem of SSSI‐included pounding problem of two adjacent symmetric in plan buildings resting on a soft soil profile excited by uniaxial earthquake loadings is investigated. To this end, a series of SSSI models considering one‐directional nonlinear impact elements between adjacent co‐planar stories and using a method for direct finite element modeling of 3D inelastic underlying soil volume has been developed to accurately study the problem. An advanced inelastic structural behavior parameter, the seismic damage index, has been considered in this study as the key nonlinear structural response of adjacent buildings. Based on the results of SSSI and fixed base case analyses presented herein, two main problems are investigated, namely, the minimum building separation distance for pounding prevention and seismic pounding effects on structural damage in adjacent buildings. The final results show that at least three times, the International Building Code 2009 minimum distance for building separation recommended value is required as a clear distance for adjacent symmetric buildings to prevent the occurrence of seismic pounding. At the International Building Code‐recommended distance, adjacent buildings experienced severe seismic pounding and therefore significant variations in storey shear forces and damage indices. Copyright © 2016 John Wiley & Sons, Ltd.