• Title/Summary/Keyword: FEMA

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Developing fragility curves and loss functions for masonry infill walls

  • Cardone, Donatello;Perrone, Giuseppe
    • Earthquakes and Structures
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    • v.9 no.1
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    • pp.257-279
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    • 2015
  • The primary objective of this study is to summarize results from previous experimental tests on laboratory specimens of RC/steel frames with masonry infills, in order to develop fragility functions that permit the estimation of damage in typical non-structural components of RC frame buildings, as a function of attained peak interstory drift. The secondary objective is to derive loss functions for such non-structural components, which provide information on the probability of experiencing a certain level of monetary loss when a given damage state is attained. Fragility curves and loss function developed in this study can be directly used within the FEMA P-58 framework for the seismic performance assessment of RC frame buildings with masonry infills.

Energy based procedure to obtain target displacement of reinforced concrete structures

  • Massumi, A.;Monavari, B.
    • Structural Engineering and Mechanics
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    • v.48 no.5
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    • pp.681-695
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    • 2013
  • Performance-based seismic design allows a structure to develop inelastic response during earthquakes. This modern seismic design requires more clearly defined levels of inelastic response. The ultimate deformation of a structure without total collapse (target displacement) is used to obtain the inelastic deformation capacity (inelastic performance). The inelastic performance of a structure indicates its performance under excitation. In this study, a new energy-based method to obtain the target displacement for reinforced concrete frames under cyclic loading is proposed. Concrete structures were analyzed using nonlinear static (pushover) analysis and cyclic loading. Failure of structures under cyclic loading was controlled and the new method was tested to obtain target displacement. In this method, the capacity energy absorption of the structures for both pushover and cyclic analyses were considered to be equal. The results were compared with FEMA-356, which confirmed the accuracy of the proposed method.

Characteristics of RC Exterior Joint Designed to Gravity Load (중력하중에 설계된 RC골조 외부접합부의 내력특성)

  • Lee, Young-Wook;Park, Hyung-Gweon;Choi, Duk-Beom;Chae, Ji-Young
    • Proceedings of the Korea Concrete Institute Conference
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    • 2010.05a
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    • pp.115-116
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    • 2010
  • To research the fragility of exterior joints of RC frame building which are not designed to seismic design code, four T shaped beam-column subassemblies are designed and tested with displacement control until to reach 3.5% story drift. From the results, the non-seismic detailed specimen failed in exterior joint before to reach to 1.0% drift, which is far less than the recommendation value of FEMA 356 and their strengths are less than 0.85 times of the nominal flexural strength.

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Explosive-Terror Risk Curve by RVS (RVS에 의한 폭발물테러 위험도 곡선)

  • Do, Ki-Young;Yoon, Sung-Won
    • Journal of Korean Association for Spatial Structures
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    • v.13 no.3
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    • pp.57-64
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    • 2013
  • Since the terrorist attacks 9.11 in 2001, the public places such as subway, department stores or office buildings have become a target of terror in major public facilities. In this paper, for the prevention of terrorist attack in domestic building, the assessments of terror risk were conducted and their relationship with building heights was discussed through FEMA 455-Rapid Visual Screening(RVS). Explosive terror risk tends to increase rapidly with building heights(H<230m), showing the correlation coefficient between total risk and building heights(H<230m) is 0.93. In addition, The average of consequences is 8.47 and that of' threat is 8.95. Vulnerability is found to be 6.62 in average.

Seismic performance evaluation of a RC special moment frame

  • Kim, Taewan;Kim, Jinkoo
    • Structural Engineering and Mechanics
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    • v.27 no.6
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    • pp.671-682
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    • 2007
  • The probability and the reliability-based seismic performance evaluation procedure proposed in the FEMA-355F was applied to a reinforced concrete moment frame building in this study. For the FEMA procedure, which was originally developed for steel moment frame structures, to be applied to other structural systems, the capacity should be re-defined and the factors reflecting the uncertainties related to capacity and demand need to be determined. To perform the evaluation procedure a prototype building was designed per IBC 2003, and inelastic dynamic analyses were conducted applying site-specific ground motions to determine the parameters for performance evaluation. According to the analysis results, distribution of the determined capacities turned out to be relatively smaller than that of the demands, which showed that the defined capacity was reasonable. It was also shown that the prototype building satisfied the target performance since the determined confidence levels exceeded the objectives for both local and global collapses.

Lateral Load Distribution Factor for Modal Pushover Analysis (고차모드 영향이 반영된 Pushover 해석을 위한 횡하중 분배계수 제안)

  • Kim, Geon-Woo;Song, Jin-Gyu
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2005.03a
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    • pp.236-243
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    • 2005
  • Nonlinear static analysis is used to quantify the resistance of the structure to lateral deformation and to gauge the mode of deformation and intensity of local demands. A simple method for the nonlinear static analysis of complex building structures subjected to monotonically increasing horizontal loading(pushover analysis) is presented. The method is designed to be a part of new methodologies for the seismic design and evaluation of structures. A variety of existing pushover analysis procedures are currently being consolidated under programs such as ATC 40 and FEMA 273. And various techniques have been recommended, including the use of constant lateral force profiles and the use of adaptive and multimodal approaches. In this paper a modal pushover analysis using design response spectra of UBC 97 is proposed. Proposed method is compared against the method in FEMA 273 and ATC 40, and results of time history analysis.

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Seismic performance evaluation of piloti-type low-rise RC apartment building (저층 RC 필로티형 집합 주택의 내진 성능 평가)

  • Lee, Han-Seon;Lee, Jeong-Jae
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.04a
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    • pp.253-256
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    • 2008
  • The objective of this study is to evaluate the seismic weakness of existing nonseismic low-rise piloti-type apartment buildings which have the irregularities of weak story, soft story, and torsion simultaneously. A prototype 4-story RC building was selected, analyzed using linear dynamic procedure and finally evaluated according to the acceptance criteria of FEM356. This building satisfies the criteria.

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Seismic Fragility Assessment of Ordinary RC Shear Walls Designed with a Nonlinear Dynamic Analysis (비선형 동적해석에 의해 내진설계된 철근콘크리트 보통 전단벽의 지진취약도 분석)

  • Jeon, Seong-Ha;Park, Ji-Hun
    • Journal of the Earthquake Engineering Society of Korea
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    • v.23 no.3
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    • pp.169-181
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    • 2019
  • Seismic performance of ordinary reinforced concrete shear wall systems commonly used in high-rise residential buildings is evaluated. Three types of shear walls exceeding 60m in height are designed by performance-based seismic design. Then, incremental dynamic analysis is performed collapse probability is assessed in accordance with the procedure of FEMA P695. As a result, story drift, plastic rotation, and compressive strain are observed to be major failure modes, but shear failure occur little. Collapse probability and collapse margin ratio of performance groups do not meet requirement of FEMA P695. It is observed that critical wall elements fail due to excessive compressive strain. Therefore, the compressive strain of concrete at the boundary area of the shear wall needs to be evaluated with more conservative acceptance criteria.

Seismic Fragility Analysis of High-Rise RC Box-Type Wall Building Structures (고층 RC 벽식 건물의 지진 취약도 분석)

  • Jeong, Gi Hyun;Lee, Han Seon;Hwang, Kyung Ran;Kwon, Oh-Sung;Kim, Sung-Jig
    • Journal of the Earthquake Engineering Society of Korea
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    • v.20 no.3
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    • pp.155-162
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    • 2016
  • Observations of the damages to high-rise reinforced concrete (RC) wall building structures caused by by recent earthquakes in Chile ($M_w$ 8.8, February 2010) and New Zealand (February 2011, $M_L$ 6.3) have generally exceeded expectations. Firstly, this study estimated the seismic damage levels of 15-story RC box-type wall building structures using the analytical models calibrated by the results of a shaking table test on a 1:5 scale 10-story RC box-type wall building model. Then, the seismic fragility analysis of the prototype model was conducted by using the SAC/FEMA method and the incremental dynamic analysis (IDA). To compensate for the uncertainties and variability of ground motion and its impacts on the prototype model, in the SAC/FEMA method, a total of 61 ground motion records were selected from 20 earthquakes, with a magnitude ranging from 5.9 to 8.8 and an epicentral distance ranging from 5 to 105km. In the IDA, a total of 11 ground motion records were used based on the uniform hazard response spectrum representing a return period of 2,475 years. As a result, the probabilities that the limits of the serviceability, damage control, and collapse prevention would be exceeded were as follows: from the SAC/FEMA method: 79%, 0.3%, and 0%, respectively; and from the IDA: 57%, 1.7%, and 0%, respectively.

Seismic Performance of Coupled Shear Wall Structural System with Relaxed Reinforcement Details (완화된 배근 상세를 갖는 병렬전단벽 구조시스템의 내진성능평가)

  • Song, Jeong-Weon;Chun, Young-Soo;Song, Jin-Kyu;Seo, Soo-Yeon;Yang, Keun-Hyeok
    • Journal of the Korea Concrete Institute
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    • v.28 no.2
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    • pp.187-196
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    • 2016
  • The current seismic design code prescribes that coupling beam should be reinforced using diagonally bundled bars. However, the use of a diagonally bundled bars has a negative effect on constructability and economic efficiency. In the present study, the seismic performance of 4 coupling beams with the different details of reinforcement was evaluated through a cyclic reversal loading test. The specimens were constructed to measure the results of the experimental variable regarding the details of shear reinforcement. Next, the seismic performance of the coupled shear wall system evaluated by methods proposed in the FEMA P695. The cyclic reversal loading test results of this study showed that the performance of coupling beams with relaxed reinforcement detail was almost similar to that of a coupling beam with the ACI detail and meet the level which requested from standard. The result of the seismic evaluation showed that all coupling beams are satisfied with the design code and seismic performance.