• Title/Summary/Keyword: capacity spectrum method (CSM)

Search Result 48, Processing Time 0.027 seconds

Capacity Spectrum Method for Seismic Performance Evaluation of Multi-Story Building Based on the Story Drift (층간변위를 기반으로 한 다층구조물의 내전성능 평가를 위한 역량스펙트럼법의 개발)

  • Kim, Sun-Pil;Kim, Doo-Kie;Kwak, Hyo-Gyoung;Ko, Sung-Huck;Seo, Hyeong-Yeol
    • Proceedings of the Computational Structural Engineering Institute Conference
    • /
    • 2007.04a
    • /
    • pp.205-210
    • /
    • 2007
  • The existing capacity spectrum method (CSM) is based on the displacement based approach for seismic performance and evaluation. Currently, in the domestic and overseas standard concerning seismic design, the CSM to obtain capacity spectrum from capacity curve and demand spectrum from elastic response spectrum is presented. In the multistory building, collapse is affected more by drift than by displacement, but the existing CSM does not work for story drift. Therefore, this paper proposes an improved CSM to estimate story drift of structures through seismic performance and evaluation. It uses the ductility factor in the A-T domain to obtain constant-ductility response spectrum from earthquake response of inelastic system using the drift and capacity curve from capacity analysis of structure.

  • PDF

Capacity Spectrum Method Based on Inelastic Displacement Ratio (비탄성변위비를 이용한 능력 스펙트럼법)

  • Han, Sang-Whan;Bae, Mun-Su
    • Journal of the Earthquake Engineering Society of Korea
    • /
    • v.12 no.2
    • /
    • pp.69-80
    • /
    • 2008
  • In this study, improved capacity spectrum method (CSM) is proposed. The method can account for higher mode contribution to the seismic response of MDOF systems. The CSM has been conveniently used for determining maximum roof displacement using both demand spectrum and capacity curve of equivalent SDOF system. Unlike the conventional CSM, the maximum roof displacement is determined without iteration using inelastic displacement ratio and R factor calculated from demand spectrum and capacity curve. Three moment resisting steel frames of 3-, 9- and 20-stories are considered to test the accuracy of the proposed method. Nonlinear response history analysis (NL-RHA) for three frames is also conducted, which is considered as an exact solution. SAC LA 10/50 and 2/50 sets of ground motions are used. Moreover, this study estimates maximum story drift ratios (IDR) using ATC-40 CSM and N2-method and compared with those from the proposed method and NL-RHA. It shows that the proposed CSM estimates the maximum IDR accurately better than the previous methods.

Evaluation of Inelastic Displacement Response for Multi-Span Bridge Structures Subjected to Earthquakes (지진하중에 대한 다경간 교량의 비탄성 변위응답 평가)

  • Song, Jong-Keol;Nam, Wang-Hyun;Chung, Yeong-Hwa
    • Journal of Industrial Technology
    • /
    • v.24 no.A
    • /
    • pp.195-204
    • /
    • 2004
  • To evaluate inelastic seismic responses of multi-span bridge structures, the capacity spectrum method(CSM) incorporating the equivalent single-degree-of freedom(ESDOF) method is presented. Application of the CSM incorporating the ESDOF method is illustrated by example analysis for symmetric and asymmetric bridge structures. To investigate an accuracy of the CSM, the maximum displacements estimated by the CSM are compared to those by inelastic time history analysis for several artificial earthquakes. The results show that the CSM provided conservative estimates of the maximum displacements for the symmetric and asymmetric bridge structures, and the trend of conservative estimates of the asymmetric bridge structures was significantly larger than that of the symmetric bridge structure.

  • PDF

Effects of Earthquake Ground Motion Sets on Performance Point of Capacity Spectrum Method (능력스펙트럼법을 이용한 성능점 결정에서 지진기록이 미치는 영향)

  • 김선우;한상환
    • Proceedings of the Computational Structural Engineering Institute Conference
    • /
    • 2001.10a
    • /
    • pp.523-528
    • /
    • 2001
  • The Capacity Spectrum Method (CSM) was first introduced in the 1970's as rapid evaluation procedure. The procedure compares the capacity of the structure (in the form of a pushover curve) with the demands on the structure (in the form of a response spectrum). The graphical intersection of the two curves approximates the response of the structure. In order to account for nonlinear inelastic behavior of the structural system, effective ductility ratios(μ) are applied to the elastic-linear response spectrum to imitate an inelastic response spectrum. CSM in ATC-40 has deficiencies such as performance point does not converge and the peak deformation of inelastic systems is to be inaccurate when compared against results of nonlinear response history analysis. The purpose of this paper is to investigate the variation of performance points of Capacity Spectrum Method (CSM) are investigated with respect to the different sets of earthquake ground motions. The earthquake sets were used in this study selected by Miranda(1993), Riddell(1991), Seed et al. (1976).

  • PDF

Accuracy of Capacity Spectrum Method for Building Structures (건축 구조물에 대한 능력스펙트럼법의 정확성 연구)

  • Min, Kyung-Won;Lee, Sang-Hyun;Park, Min-Kyu;Lee, Young-Chul;Jung, Ran
    • Proceedings of the Computational Structural Engineering Institute Conference
    • /
    • 2003.04a
    • /
    • pp.27-34
    • /
    • 2003
  • Capacity Spectrum Method (CSM) defined in ATC-40 or FEMA-273 is a most widely used static inelastic analysis method to evaluate the performance level of the existing structures. In CSM, however, uncertainties and errors exist when lateral forces such as earthquake and wind loads are analyzed into equivalent static loads. This paper examines the accuracy of CSM for different structural parameters, such as natural frequency, yield strength and hardening ratio, and various soil conditions by comparing the estimated values to exact solutions obtained by time history analysis. Results indicate that the accuracy of CSM, in general, is influenced mostly by hardening ratio.

  • PDF

Seismic Performance Evaluation of Multi-Span Bridges using CSM and modified DCM (역량스펙트럼 방법과 수정변위계수법을 이용한 다경간 교량의 내진성능 평가)

  • Nam, Wang-Hyun;Song, Jong-Keol;Chung, Yeong-Hwa
    • Journal of Industrial Technology
    • /
    • v.26 no.B
    • /
    • pp.119-126
    • /
    • 2006
  • Capacity spectrum method(CSM) of ATC-40(1996) and displacement coefficient method(DCM)of FEMA-273(1997) are applied to evaluate the seismic performance of bridges. In this study, equivalent response is obtained from nonlinear static analysis for the 3spans continues bridge and nonlinear maximum displacement response is calculated using CSM and DCM. Nonlinear maximum displacement response of DCM is larger than this of CSM. It is method that DCM can evaluate target displacement and ductility of structural to be easy and simple, but tend to overestimate the maximum displacement response. Therefore, this method is mainly used at preparation design level to evaluate the structural response. It is not desirable to evaluate the seismic performance using DCM.

  • PDF

Effects of Strength Reduction Factors for Capacity Spectrum Analysis of Bridge Structures using Inelastic Demand Spectrum (비탄성 요구도 스펙트럼을 이용한 교량구조물의 역량스펙트럼 해석에 대한 강도감소계수의 영향)

  • Song, Jong-Keol;Jin, He-Shou;Jang, Dong-Hui
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • v.28 no.1A
    • /
    • pp.25-37
    • /
    • 2008
  • The capacity spectrum method (CSM) is a simple and graphical seismic analysis procedure. Originally, it has been developed for buildings, but now its applicability has been extended to bridge structures. It is based on the capacity curve estimated by pushover analysis and demand spectrum reduced from linear elastic design spectrum by using effective damping or strength reduction factor. In this paper, the inelastic demand spectrum as the reduced demand spectrum is calculated from the linear elastic design spectrum by using the several formulas for the strength reduction factor. The effects of the strength reduction factor for the capacity spectrum analysis are evaluated for 3 types of symmetric and asymmetric bridge structures. To investigate an accuracy of the CSM which several formulas for strength reduction factor were applied, the maximum displacements estimated by the CSM are compared with the results obtained by nonlinear time history analysis for 8 artificially generated earthquakes. The maximum displacements estimated by the CSM using the SJ formula among the several strength reduction factors provide the most accurate agreement with those calculated by the inelastic time history analysis.

Evaluation of Seismic Response of Multi-Degree of Freedom Bridge Structures According to The ESDOF Method (등가단자유도 방법에 따른 다자유도 교량의 지진응답평가)

  • Song, Jong-Keol;Nam, Wang-Hyun;Chung, Yeong-Hwa
    • Journal of Industrial Technology
    • /
    • v.25 no.A
    • /
    • pp.23-30
    • /
    • 2005
  • The capacity spectrum method(CSM) can be used for the evaluation of inelastic maximum response of structures and has been recently used in the seismic design using the incorporation of pushover analysis and response spectrum method. To efficiently evaluate seismic performance of multi-degree-of freedom(MDOF) bridge structures, it is important that the equivalent response of MDOF bridge structures should be calculated. To calculate the equivalent response of MDOF system, equivalent responses are obtained by using Song method, Fajfar method and Calvi method. Also, those responses are applied to CSM method and seismic performance of bridge according to the ESDOF method are compared and evaluated straightforwardly.

  • PDF

Probabilistic capacity spectrum method considering soil-structure interaction effects (지반-구조물 상호작용 효과를 고려한 확률론적 역량스펙트럼법)

  • Nocete, Chari Fe M.;Kim, Doo-Kie;Kim, Dong-Hyawn;Cho, Sung-Gook
    • Proceedings of the Computational Structural Engineering Institute Conference
    • /
    • 2008.04a
    • /
    • pp.65-70
    • /
    • 2008
  • The capacity spectrum method (CSM) is a deterministic seismic analysis approach wherein the expected seismic response of a structure is established as the intersection of the demand and capacity curves. Recently, there are a few studies about a probabilistic CSM where uncertainties in design factors such as material properties, loads, and ground motion are being considered. However, researches show that soil-structure interaction also affects the seismic responses of structures. Thus, their uncertainties should also be taken into account. Therefore, this paper presents a probabilistic approach of using the CSM for seismic analysis considering uncertainties in soil properties. For application, a reinforced concrete bridge column structure is employed as a test model. Considering the randomness of the various design parameters, the structure's probability of failure is obtained. Monte Carlo importance sampling is used as the tool to assess the structure's reliability when subjected to earthquakes. In this study, probabilistic CSM with and without consideration of soil uncertainties are compared and analyzed. Results show that the analysis considering soil structure interaction yields to a greater probability of failure, and thus can lead to a more conservative structural design.

  • PDF

Seismic Fragility Analysis of Lightning Arrester using Capacity Spectrum Method (역량스펙트럼 방법을 이용한 피뢰기의 지진취약도 해석)

  • Kim, Gwang-Jeon;Song, Jong-Keol
    • Journal of the Computational Structural Engineering Institute of Korea
    • /
    • v.27 no.4
    • /
    • pp.255-263
    • /
    • 2014
  • In this paper, seismic fragility analysis of lightning arrester is performed using capacity spectrum method(CSM). Since seismic fragility analysis of structure with many structural members is required to calculate many inelastic responses for several tens or hundreds of ground motions, simple method such as CSM is more appropriate than response history analysis(RHA). In general, accuracy of seismic response evaluated by CSM is less than that by RHA. In order to increase accuracy of CSM, equivalent SDOF method and performance point calculation technique are applied to CSM. Seismic fragility method proposed by Shinozuka et al. is used. In order to evaluate site effect of ground motions on seismic fragility, 60 different site classification earthquakes are selected as input ground motions. From the seismic fragility curves of lightning arrester evaluated by CSM and RHA, it can be observed that the seismic fragility curves evaluated by CSM are very similar to those by RHA. Also, it can be observed that main seismic failure mode of lightning arrest is bushing breakage.