Two-Dimensional Capacity Spectrum Method and Seismic Damage Assessment for RC Structures

2011 ◽  
Vol 243-249 ◽  
pp. 79-88
Author(s):  
Hao Xiang He ◽  
Hong Nan Li

The force-deformation curve of a reinforced concrete structure in push-over analysis is used to compute the corresponding damage index. A simplified and practical method is established for seismic damage assessment in combination with capacity spectrum method. The two-dimensional capacity spectrum method and the combination of the damage in two directions are discussed. A numerical example using single and double horizontal capacity method and time history analysis demonstrate that the response and damage of structure can be computed accurately in the two-dimensional capacity method. The common trend of structural torsional response can also be reflected. The results show the two-dimensional capacity method is valid and simple.

Author(s):  
Xinzheng Lu ◽  
Qingle Cheng ◽  
Yuan Tian ◽  
Yuli Huang

ABSTRACT Regional ground-motion simulation is important for postearthquake seismic damage assessment. Herein, a ground-motion simulation method using recorded ground motions is proposed. Inverse-distance-weighted interpolation of the response spectra is performed to obtain the response spectrum at the target location. Then the ground-motion time history for the target location is obtained by correcting the nearest-station records using the continuous wavelet transform. An evaluation measure for the accuracy of the predicted ground motion, that is, the response-spectrum error, is introduced, and its relationship with the seismic damage of regional buildings is determined via a city-scale nonlinear time-history analysis. The response-spectrum errors under different site conditions, distances, and elevation differences are analyzed. The application conditions for the proposed method are subsequently outlined. The Tsinghua campus is examined as a case study to validate the method. Finally, downtown San Francisco under an Mw 7.0 simulated earthquake on the Hayward fault is selected as an example to demonstrate the proposed method. The proposed method overcomes the difficulties in determining the intrastation ground motions and provides valuable input to postearthquake seismic damage assessment.


2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Haoxiang He ◽  
Maolin Cong ◽  
Yongwei Lv

A global damage index based on multiple linear force-deformation curves in pushover analysis is presented to evaluate the integrated damage of reinforced concrete structure. The modified coefficient is provided considering the cyclic load and hysteresis energy. The number of inelastic cycles and the coefficient of hysteresis energy concentration are also introduced as damage indices. Hence, multiple damage indices about displacement and energy for performance-based design are considered. The relation of multiple damage indices or factors and the fuzzy damage set is presented by comprehensive fuzzy evaluation; hence, a performance-based multiple fuzzy seismic damage-assessment method for reinforced concrete frame structures is established. The method can be accomplished based on pushover analysis, code spectrum, and capacity spectrum method. The fuzzy seismic damage-assessment method is verified through nonlinear analysis four different structures and the corresponding results and assessment conclusions are accurate.


2021 ◽  
Vol 11 (6) ◽  
pp. 2687
Author(s):  
Ahmad Naqi ◽  
Taiki Saito

This study proposes a capacity spectrum Method (CSM)-based procedure to estimate the maximum seismic performance of steel buildings passively controlled with bilinear oil dampers. In the proposed CSM, the maximum seismic response of a building was estimated, in the acceleration-displacement response spectrum, as the intersection between the capacity curve and the damping-adjusted demand curves, using the equivalent linearization method. The building equivalent damping ratio was determined by the sum of the inherent damping, and the square root of sum of squares (SRSS) of the hysteretic damping and the viscous damping of the supplemental oil devices. The calculation steps of the proposed CSM are explained in detail based on the equivalent single degree of freedom (ESDOF) system, and its accuracy was examined by comparison with time history analysis (THA) results. Two model steel buildings of 4 and 10 stories, uniformly equipped with oil dampers along the height, were subjected to six selected earthquake ground motions scaled to be compatible with Level-2 earthquakes, as defined in the Japanese Building Standard Law. The seismic performance of the buildings was estimated by the proposed CSM procedure and compared with the results of nonlinear THA in terms of the maximum story displacements and the shear forces. It was observed that the proposed CSM scheme provided a satisfactory accuracy to assess the maximum nonlinear response of steel buildings passively controlled with oil dampers.


2014 ◽  
Vol 14 (02) ◽  
pp. 1350062 ◽  
Author(s):  
GHOLAMREZA GHODRATI AMIRI ◽  
PEJMAN NAMIRANIAN

Simplified methods for analyzing seismically isolated structures are always used either as a design procedure or as checking criteria for the results of time history procedure. The main purpose of this study is to evaluate the accuracy of one of these methods, the capacity spectrum method (CSM), in predicting the seismic demands, such as isolator displacement and maximum base shear force, of structures with triple pendulum bearings (TPBs) under bidirectional near-field ground motions. By comparing the results of this method with those of the nonlinear time history analysis (NTHA), it can be concluded that the CSM is able to predict the maximum isolator displacement and base shear of the structure with acceptable accuracy. It should be noted that for softer soil site conditions, the values of demand calculated by CSM are sometimes underestimated compared with the results of NTHA, especially when the effective period of system exceeds 3.0 s or when the TPB works on the fifth regime of its pendulum mechanism.


2010 ◽  
Vol 163-167 ◽  
pp. 1063-1067
Author(s):  
Qing Xuan Shi ◽  
Qiu Wei Wang ◽  
Kun Yang

To further understand displacement based seismic theory of building structures, the seismic performance evaluation using capacity spectrum method related to damping is carried out for the reinforced concrete frame-shear wall model structure of a thermal power main plant. By comparing with time-history analysis results, it can be seen that some problems such as equivalence of multi-degree-of-freedom system and value of equivalent damping ratio in capacity spectrum method remains to be further investigated. Force and displacement response of structures and plastic hinges position of all members could be obtained through nonlinear push-over analysis after determining the top displacement; weak parts and damage pattern of structures could also be easily found out by this method. At last, research shows that dynamic time-history analysis can be replaced by static push-over analysis, which is regarded as an exact seismic performance evaluation method by contrast.


2021 ◽  
pp. 147592172199621
Author(s):  
Enrico Tubaldi ◽  
Ekin Ozer ◽  
John Douglas ◽  
Pierre Gehl

This study proposes a probabilistic framework for near real-time seismic damage assessment that exploits heterogeneous sources of information about the seismic input and the structural response to the earthquake. A Bayesian network is built to describe the relationship between the various random variables that play a role in the seismic damage assessment, ranging from those describing the seismic source (magnitude and location) to those describing the structural performance (drifts and accelerations) as well as relevant damage and loss measures. The a priori estimate of the damage, based on information about the seismic source, is updated by performing Bayesian inference using the information from multiple data sources such as free-field seismic stations, global positioning system receivers and structure-mounted accelerometers. A bridge model is considered to illustrate the application of the framework, and the uncertainty reduction stemming from sensor data is demonstrated by comparing prior and posterior statistical distributions. Two measures are used to quantify the added value of information from the observations, based on the concepts of pre-posterior variance and relative entropy reduction. The results shed light on the effectiveness of the various sources of information for the evaluation of the response, damage and losses of the considered bridge and on the benefit of data fusion from all considered sources.


Sign in / Sign up

Export Citation Format

Share Document