• Title/Summary/Keyword: inelastic structure

Search Result 333, Processing Time 0.024 seconds

Experimental and analytical investigation on seismic behavior of RC framed structure by pushover method

  • Sharma, Akanshu;Reddy, G.R.;Eligehausen, R.;Vaze, K.K.
    • Structural Engineering and Mechanics
    • /
    • v.39 no.1
    • /
    • pp.125-145
    • /
    • 2011
  • Pushover analysis has gained significant popularity as an analytical tool for realistic determination of the inelastic behaviour of RC structures. Though significant work has been done to evaluate the demands realistically, the evaluation of capacity and realistic failure modes has taken a back seat. In order to throw light on the inelastic behaviour and capacity evaluation for the RC framed structures, a 3D Reinforced concrete frame structure was tested under monotonically increasing lateral pushover loads, in a parabolic pattern, till failure. The structure consisted of three storeys and had 2 bays along the two orthogonal directions. The structure was gradually pushed in small increments of load and the corresponding displacements were monitored continuously, leading to a pushover curve for the structure as a result of the test along with other relevant information such as strains on reinforcement bars at critical locations, failure modes etc. The major failure modes were observed as flexural failure of beams and columns, torsional failure of transverse beams and joint shear failure. The analysis of the structure was by considering all these failure modes. In order to have a comparison, the analysis was performed as three different cases. In one case, only the flexural hinges were modelled for critical locations in beams and columns; in second the torsional hinges for transverse beams were included in the analysis and in the third case, joint shear hinges were also included in the analysis. It is shown that modelling and capturing all the failure modes is practically possible and such an analysis can provide the realistic insight into the behaviour of the structure.

Study of Inelastic Responses of a 1:12 Scale 10-Story R.C. Frame-Wall Structure (1:12축소 10층 R.C. 골조-벽식 구조의 비선형 거동 연구)

  • 이한선;김상호;유은진
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2000.10b
    • /
    • pp.867-872
    • /
    • 2000
  • A 1:12 scale 10-story RC building structure was constructed and the experiment was performed. The test results are presented and compared with the results of the analysis conducted with DRAIN-2DX. It is concluded that some local deformations cannot be described reasonably with the wall model using only Plastic Hinge Beam-Column Element(TYPE02) in DRAIN-2DX whereas the strength and stiffness of the whole structure can be predicted with high reliability.

Development of a Seismic Damage Assessment Program for NPP Containment Structure (원전격납건물 지진피해평가 프로그램 개발)

  • 고현무;신현목;최강룡;정대열;현창헌;조호현;김태훈
    • Proceedings of the Earthquake Engineering Society of Korea Conference
    • /
    • 2003.03a
    • /
    • pp.118-125
    • /
    • 2003
  • Seismic damage assessment program for containment structure is developed. The program has been established through the combination of inelastic seismic analysis program and 3-D animation program. Damage indices at finite element level and structural level have been introduced for the seismic damage assessment. The seismic damage assessment program makes it possible to analyze in real-time the actual resistance capacity and damage level of containment structure. It will be expected that the program enables to establish the measures more quickly under the earthquake event.

  • PDF

Direct Inelastic Strut-Tie Model Using Secant Stiffness (할선강성을 이용한 직접 비탄성 스트럿-타이 모델)

  • Park Hong-Gun;Kim Yun-Gon;Eom Tae-Sung
    • Journal of the Korea Concrete Institute
    • /
    • v.17 no.2 s.86
    • /
    • pp.201-212
    • /
    • 2005
  • A new strut-tie model using secant stiffness, Direct Inelastic Strut-Tie Model, was developed. Since basically the proposed design method uses linear analysis, it is convenient and stable in numerical analysis. At the same time, the proposed design method can accurately estimate the inelastic strength and ductility demands of struts and ties because it can analyzes the inelastic behavior of structure using iterative calculations for secant stiffness. In the present study, the procedure of the proposed design method was established, and a computer program incorporating the proposed method was developed. Design examples using the proposed method were presented, and its advantages were highlighted by the comparison with the traditional strut-tie model. The Direct Inelastic Strut-Tie Model, as an integrated analysis/design method, can directly address the design strategy intended by the engineer to prevent development of macro-cracks and brittle failure of struts. Since the proposed model can analyze the inelastic deformation, indeterminate strut-tie model can be used. Also, since the proposed model controls the local deformations of struts and ties, it can be used as a performance-based design method for various design criteria.

Implications of the effects of gravity load for earthquake resistant design of multistory building structurtes (고층건물의 내진설계에 미치는 중력하중의 영향)

  • 이동근;이석용
    • Computational Structural Engineering
    • /
    • v.6 no.3
    • /
    • pp.67-80
    • /
    • 1993
  • This paper presents the results of an analytical study to evaluate the inelastic seismic response characteristics of multistory building structures, the effects of gravity load on the seismic responses and its implications on the earthquake resistant design. Static analyses for incremental lateral force and nonlinear dynamic analyses for earthquake motions were performed to evaluate the seismic response of example multistory building structures. Most of considerations are placed on the distribution of inelastic responses over the height of the structure. When an earthquake occurs, bending moment demand is increased considerably from the top to the bottom of multistory structures, so that differences between bending moment demands and supplies are greater in lower floos of multistory structures. As a result, for building structures designed by the current earthquake resistant design procedure, inelastic deformations for earthquake ground motions do not distribute uniformly over the height of structures and those are induced mainly in bottom floors. In addition, gravity load considerded in design procedure tends to cause much larger damages in lower floors. From the point of view of seismic responses, gravity load affects the initial yield time of griders in earlier stage of strong earthquakes and results in different inelastic responses among the plastic hinges that form in the girders of a same floor. However, gravity load moments at beam ends are gradually reduced and finally fully relaxed after a structure experiences some inelastic excursions as a ground motion is getting stronger. Reduction of gravity load moment results in much increased structural damages in lower floors building structures. The implications of the effects of gravity load for seismic design of multistory building structures are to reduce the contributions of gravity load and to increased those of seismic load in determination of flexual strength for girders and columns.

  • PDF

Experimental Study on the Inelastic Behavior of Single-layer Latticed Dome with New Connection (새로운 접합상세를 가진 단층 래티스 돔의 비탄성 거동에 관한 실험연구)

  • Kim, Myeong Han;Oh, Myoung Ho;Jung, Seong Yeol;Kim, Sang Dae
    • Journal of Korean Society of Steel Construction
    • /
    • v.21 no.2
    • /
    • pp.145-154
    • /
    • 2009
  • This study discusses the inelastic behavior of single-layer latticed dome, which consists of a tubular truss member and newly proposed joint sections, through a loading test on a scaled-down structure. The loading test was performed under displacement control conditions, using loading transfer system for the same value of point loads on all joints. The maximum applied load was nearly 1.6 times of the design load, and structural failure occurred after exceeding the compressive yielding in some members. Structural displacement was maintained up to the limit of the oil jack. The behavior of the latticed dome from the loading test was analyzed according to the order of loading steps.

A Study on Inelastic Behavior of an Asymmetric Tall Building (비대칭 초고층건물의 비탄성거동에 관한 연구)

  • 윤태호;김진구;정명채
    • Journal of the Earthquake Engineering Society of Korea
    • /
    • v.1 no.3
    • /
    • pp.37-44
    • /
    • 1997
  • In this paper, the inelastic behavior of an asymmetric tall building is investigated. The asymmetry in rigidity caused by the structural asymmetry induces torsional as well as lateral deformation. The inelastic analysis of such an asymmetric structure is difficult to carry out with a planar model and thus requires a full three dimensional model. In this paper a 102 story unsymmetric tall building is analized by static push-over procedure and its behavior is investigated. The analysis are performed with and without floor rotation to compare the results. According to the results the static behavior of the model building, as expected, turned out to be dependent heavily an the asymmetry of the plan shapes of the building.

  • PDF

Moment Redistribution for Moment-Resisting Frames using Secant Stiffness Analysis Method (할선강성해석법을 이용한 모멘트저항골조의 모멘트 재분배)

  • Park, Hong-Gun;Kim, Chang-Soo;Eom, Tae-Sung
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2008.11a
    • /
    • pp.221-224
    • /
    • 2008
  • A secant stiffness linear analysis method was developed for moment redistribution of moment-resisting frames. In the proposed method, rotational spring models are used for plastic hinges of the members whose flexural moments are needed to be redistributed. At the plastic hinges, secant stiffness is used to address the effect of the flexural stiffness reduced by inelastic deformation. Linear analysis is repeated with adjusted secant stiffness until the flexural equilibrium is satisfied in the structure and members. By using the secant stiffness analysis, the effect of the inelastic deformation on the moment redistribution can be considered. Further, the safety of plastic hinges can be evaluated by comparing the inelastic rotation resulting from the secant stiffness analysis with the rotational capacity of the plastic hinges. For verification, the proposed method was applied to a continuous beam tested in previous study. A application example for a multiple story moment-resisting frame was presented.

  • PDF

Seismic design of irregular space steel frames using advanced methods of analysis

  • Vasilopoulos, A.A.;Bazeos, N.;Beskos, D.E.
    • Steel and Composite Structures
    • /
    • v.8 no.1
    • /
    • pp.53-83
    • /
    • 2008
  • A rational and efficient seismic design methodology for irregular space steel frames using advanced methods of analysis in the framework of Eurocodes 8 and 3 is presented. This design methodology employs an advanced static or dynamic finite element method of analysis that takes into account geometrical and material non-linearities and member and frame imperfections. The inelastic static analysis (pushover) is employed with multimodal load along the height of the building combining the first few modes. The inelastic dynamic method in the time domain is employed with accelerograms taken from real earthquakes scaled so as to be compatible with the elastic design spectrum of Eurocode 8. The design procedure starts with assumed member sections, continues with the checking of the damage and ultimate limit states requirements, the serviceability requirements and ends with the adjustment of member sizes. Thus it can sufficiently capture the limit states of displacements, rotations, strength, stability and damage of the structure and its individual members so that separate member capacity checks through the interaction equations of Eurocode 3 or the usage of the conservative and crude q-factor suggested in Eurocode 8 are not required. Two numerical examples dealing with the seismic design of irregular space steel moment resisting frames are presented to illustrate the proposed method and demonstrate its advantages. The first considers a seven storey geometrically regular frame with in-plan eccentricities, while the second a six storey frame with a setback.

Nonlinear Inelastic Analysis of 3-Dimensional Steel Structures Using Fiber Elements (화이버 요소를 이용한 3차원 강구조물의 비선형 비탄성 해석)

  • Kim, Seung-Eock;Oh, Jung-Ryul
    • Journal of the Computational Structural Engineering Institute of Korea
    • /
    • v.19 no.4 s.74
    • /
    • pp.347-356
    • /
    • 2006
  • In this paper, practical nonlinear inelastic analysis method of 3-dimensional steel structures accounting for gradual yielding with fibers on a section is developed. Geometric nonlinearities of member(p-$\delta$) and frame(p-$\Delta$) are accounted for by using stability functions. Residual stresses are considered by assigning initial stresses to the fiber on the section. The elastic core in a section is investigated at every loading step to determine the axial and bending stiffness reduction. The strain reversal effect is captured by investigating the stress change of each fiber. The proposed analysis proves to be useful in applying for practical analysis and design of three-dimensional steel frames.