• Title/Summary/Keyword: Collapse behavior analysis

Search Result 272, Processing Time 0.023 seconds

Reliability analysis of double-layer domes with stochastic geometric imperfections

  • Gordini, Mehrdad;Habibi, Mohammad Reza;Sheidaii, Mohammad Reza;Tahamouliroudsari, Mehrzad
    • Advances in Computational Design
    • /
    • v.2 no.2
    • /
    • pp.133-146
    • /
    • 2017
  • This study aimed to investigate the effect of initial member length an imperfection in the load carrying capacity of double-layer domes space structures. First, for the member length imperfection of each member, a random number is generated from a normal distribution. Thereupon, the amount of the imperfection randomly varies from one member to another. Afterwards, based on the Push Down analysis, the collapse behavior and the ultimate capacity of the considered structure is determined using nonlinear analysis performed by the OpenSees software and this procedure is repeated numerous times by Monte Carlo simulation method. Finally, the reliability of structures is determined. The results show that the collapse behavior of double-layer domes space structures is highly sensitive to the random distribution of initial imperfections.

Collapse Modeling of model RC Structure Using Applied Element Method (AEM을 이용한 철근콘크리트 모형 구조물의 붕괴 모델링)

  • Park, Hoon;Suk, Chul-Gi;Kim, Seung-Kon
    • Tunnel and Underground Space
    • /
    • v.19 no.1
    • /
    • pp.43-51
    • /
    • 2009
  • In order to analyze collapse behavior of structure containing irregular and large displacement, many numerical analyses have been conducted. In this study, using a new method, Applied Element Method (AEM) for collapse analysis of structures, collapse behavior of model RC structures Is simulated. From these simulations results, displacement of X-direction (or horizontal) and displacement of Y-direction (or vertical) is similar to that of mode) RC structures. It is confirmed that collapse behavior of structures using AEN is reliable accurately simulated with that of model RC structures.

Effect of Internal Pressure on the Behavior of Wall Thinned Elbow under In-Plane Bending (In-plane 굽힘 조건에서 감육엘보우 거동에 미치는 내압의 영향)

  • Kim, Jin-Weon;Kim, Tae-Soon;Park, Chi-Yong
    • Proceedings of the KSME Conference
    • /
    • 2004.04a
    • /
    • pp.268-273
    • /
    • 2004
  • This study is conducted to clarify the effect of internal pressure on the deformation and collapse behaviors of wall thinned elbow under in-plane bending moment. Thus the nonlinear three-dmensional finite element analyses were performed to obtain the moment-rotation curve of elbow contatining various wall thinning defects located at intrados and extrados under in-plane bending (closing and opening modes) with internal pressure of $0{\sim}15MPa.$ From the results of analysis, the effect of internal of collapse moment of elbow on the global deformation behavior of wall thinned elbow was discussed, and the dependence of collapse moment of elbow on the magnitude of internal pressure was investigated under different loading mode, defect location, and defect shape.

  • PDF

Evaluation of Progressive Collapse Resisting Capacity of Special Concentrically Braced Frames (특수 중심가새골조의 연쇄붕괴 저항능력 평가)

  • Lee, Young-Ho;Kim, Jin-Koo;Choi, Hyun-Hoon
    • Proceedings of the Computational Structural Engineering Institute Conference
    • /
    • 2008.04a
    • /
    • pp.319-324
    • /
    • 2008
  • In this study the progressive collapse potential of special concentrically braced frames were investigated using the nonlinear static. All of seven different brace types were considered. According to the pushdown analysis results, most braced frames designed according to current design codes satisfied the design guidelines for progressive collapse initiated by loss of a first story mid-column; however most model structures showed brittle failure mode. This was caused by buckling of columns after compressive braces buckled. Among the braced frames considered, the inverted-V type braced frames showed superior ductile behavior during progressive collapse.

  • PDF

Axial Impact Collapse Analysis of Spot Welded Hat and Double-hat Shaped Section Members Using an Explicit Finite Element Code

  • Cha, Cheon-Seok;Kim, Young-Nam;Kim, Sun-Kyu;Im, Kwang-Hee;Yang, In-Young
    • Journal of Mechanical Science and Technology
    • /
    • v.16 no.1
    • /
    • pp.32-38
    • /
    • 2002
  • The purpose of this study is to analyze the collapse characteristics of widely used spot welded section members (hat and double hat section, nembers of vehicles) which possess the greatest energy absorbing capacity In an axial impact collapse. This study also suggests how the collapse load and deformation mode are obtained under impact. In the program system presented in this study, an explicit finite element code, LS-DY7A3D, is adopted for simulating complicated collapse behavior of the hat and double hat shaped section members with respect to section dimensions and spot weld pitches. Comparing the results with experiments, the simulation has been verified under a velocity of 7.19 m/sec (impact energy of 1034J)

Reduced Degree of Freedom Modeling for Progressive Collapse Analysis of Tall Buildings using Applied Element Method (응용 요소법을 이용한 초고층 건물의 축소 모델링 연쇄붕괴 해석)

  • Kim, Han-Soo;Wee, Hae-Hwan
    • Journal of the Korea Concrete Institute
    • /
    • v.26 no.5
    • /
    • pp.599-606
    • /
    • 2014
  • Since progressive collapse of tall buildings can cause enormous damage, it should be considered during the design phase of tall buildings. The progressive collapse analysis of tall buildings using finite element methods is almost impossible due to the vast amount of computing time. In this paper, applied element method was evaluated as an alternative to the finite element method. Reduced DOFs modeling technique was proposed to enable the progressive collapse analysis of tall buildings. The reduced DOFs model include only the part which is subjected to direct damage from blast load and the structural properties such as mass, transferred load and stiffness of excluded parts are accumulated into the top story of the reduced DOFs model. The proposed modeling technique was applied to the progressive collapse analysis of 20-story RC building using three collapse scenarios. The reduced DOFs model showed similar collapse behavior to the whole model while the computing time was reduced by 30%. The proposed modeling technique can be utilized in the progressive collapse analysis of tall buildings due to abnormal loads.

Impact of initial damage path and spectral shape on aftershock collapse fragility of RC frames

  • Liu, Yang;Yu, Xiao-Hui;Lu, Da-Gang;Ma, Fu-Zi
    • Earthquakes and Structures
    • /
    • v.15 no.5
    • /
    • pp.529-540
    • /
    • 2018
  • The influences of initial damage paths and aftershock (AS) spectral shape on the assessment of AS collapse fragility are investigated. To do this, a four-story ductile reinforced concrete (RC) frame structure is employed as the study case. The far-field earthquake records recommended by FEMA P695 are used as AS ground motions. The AS incremental dynamic analyses are performed for the damaged structure. To examine the effect of initial damage paths, a total of six kinds of initial damage paths are adopted to simulate different initial damage states of the structure by pushover analysis and dynamic analysis. For the pushover-based initial damage paths, the structure is "pushed" using either uniform or triangle lateral load pattern to a specified damage state quantified by the maximum inter-story drift ratio. Among the dynamic initial damage paths, one single mainshock ground motion or a suite of mainshock ground motions are used in the incremental dynamic analyses to generate a specified initial damage state to the structure. The results show that the structure collapse capacity is reduced as the increase of initial damage, and the initial damage paths show a significant effect on the calculated collapse capacities of the damaged structure (especially at severe damage states). To account for the effect of AS spectral shape, the AS collapse fragility can be adjusted at different target values of ${\varepsilon}$ by using the linear correlation model between the collapse capacity (in term of spectral intensity) and the AS ${\varepsilon}$ values, and coefficients of this linear model is found to be associated with the initial damage states.

Progressive collapse resistance of low and mid-rise RC mercantile buildings subjected to a column failure

  • Demir, Aydin
    • Structural Engineering and Mechanics
    • /
    • v.83 no.4
    • /
    • pp.563-576
    • /
    • 2022
  • This study aimed to evaluate the progressive collapse potential of buildings designed using conventional design codes for the merchant occupancy classification and subjected to a sudden column failure. For this purpose, three reinforced concrete buildings having different story numbers were designed according to the seismic design recommendations of TSCB-2019. Later on, the buildings were analyzed using the GSA-2016 and UFC 4-023-03 to observe their progressive collapse responses. Three columns were removed independently in the structures from different locations. Nonlinear dynamic analysis method for the alternate path direct design approach was implemented for the design evaluation. The plasticity of the structural members was simulated by using nonlinear fiber hinges. The moment, axial, and shear force interaction on the hinges was considered by the Modified Compression Field Theory. Moreover, an existing experimental study investigating the progressive collapse behavior of reinforced concrete structures was used to observe the validation of nonlinear fiber hinges and the applied analysis methodology. The study results deduce that a limited local collapse disproportionately more extensive than the initial failure was experienced on the buildings designed according to TSCB-2019. The mercantile structures designed according to current seismic codes require additional direct design considerations to improve their progressive collapse resistance against the risk of a sudden column loss.

Difference analysis of the collapse behaviors of the single-story beam-column assembly and multi-story planar frame

  • Zheng Tan;Wei-Hui Zhong;Bao Meng;Xing-You Yao;Yu-Hui Zheng;Yao Gao;Shi-Chao Duan
    • Steel and Composite Structures
    • /
    • v.50 no.3
    • /
    • pp.265-280
    • /
    • 2024
  • The collapse behavior observed in single-story beam-column assembly (SSBCA) do not accurately represent the actual overall stress characteristic of multi-story frame structure (MSFS) under column loss scenario owing to ignoring the interaction action among different stories, leading to a disconnection between the anti-collapse behaviors of "components" and "overall structures", that is, the anti-collapse performance of frame structures with two different structural scales has not yet formed a combined force. This paper conducts a numerical and theoretical study to explore the difference of the collapse behaviors of the SSBCA and MSFS, and further to reveal the internal force relationships and boundary constraints at beam ends of models SSBCA and MSFS. Based on the previous experimental tests, the corresponding refined numerical simulation models were established and verified, and comparative analysis on the resistant-collapse performance was carried out, based on the validated modeling methods with considering the actual boundary constraints, and the results illustrates that the collapse behaviors of the SSBCA and MSFS is not a simple multiple relationship. Through numerical simulation and theoretical analysis, the development laws of internal force in each story beam under different boundary constraints was clarified, and the coupling relationship between the bending moment at the most unfavorable section and axial force in the composite beam of different stories of multi story frames with weld cover-plated flange connections was obtained. In addition, considering the effect of the yield performance of adjacent columns on the anti-collapse bearing capacities of the SSBCA and MSFS during the large deformation stages, the calculation formula for the equivalent axial stiffness at the beam ends of each story were provided.

Equivalent Static Analysis of Progressive Collapse Using Equivalent Load for Stiffness (강성등가하중을 이용한 등가정적 연쇄붕괴 해석)

  • Hwang, Young-Chul;Kim, Gye-Joong;Kim, Chee-Kyeong
    • Proceedings of the Computational Structural Engineering Institute Conference
    • /
    • 2007.04a
    • /
    • pp.375-380
    • /
    • 2007
  • The goal of this paper is to develop a rational static method which consider efficiently the dynamic effect of the gravity load following sudden removal of element. For this goal this paper introduce the equivalent load for element stiffness which is a preceding research result and will develop equivalent static analysis which will be able to predict the maximum behavior considering dynamic effect. Some examples are provided to verify it. Equivalent static analysis is compared with the analysis method which is recommended by the GSA2003 guidelines and the time-history analysis which is the most accurate for dynamic behavior.

  • PDF