• Title/Summary/Keyword: seismic inelastic response

Search Result 225, Processing Time 0.028 seconds

Response of Bridge Piers Retrofitted by Stainless Steel Wire under Simulated Seismic Loading (내진 모사하중에 의한 스테인레스강 와이어 보강 교각의 응답)

  • Choi, Jun Hyeok;Kim, Sung Hoon;Lee, Do Hyung
    • Journal of Korean Society of Steel Construction
    • /
    • v.21 no.4
    • /
    • pp.343-350
    • /
    • 2009
  • In the present study, a new seismic retrofitting method that employs both a stainless steel wire mesh and a permeable polymer concrete mortar was proposed for reinforced concrete bridge piers with nonseismic design details. For this purpose, a total of six nonseismically designed bridge piers were tested under lateral load reversals. The test results reveal that nonseismically designed piers with lap splices need to be retrofitted to resist earthquake induced forces. In addition, it was proven that the proposed retrofitting method can be useful in improving the strength, stiffness, and energy dissipation capacities of bridge piers designed nonseismically. It is thus expected that the proposed method may provide an improved ductility capacity without sudden softening of strength for bridge piers excursing inelastic displacement range.

Deformation-based vulnerability functions for RC bridges

  • Elnashai, A.S.;Borzi, B.;Vlachos, S.
    • Structural Engineering and Mechanics
    • /
    • v.17 no.2
    • /
    • pp.215-244
    • /
    • 2004
  • There is an ever-increasing demand for assessment of earthquake effects on transportation structures, emphasised by the crippling consequences of recent earthquakes hitting developed countries reliant on road transportation. In this work, vulnerability functions for RC bridges are derived analytically using advanced material characterisation, high quality earthquake records and adaptive inelastic dynamic analysis techniques. Four limit states are employed, all based on deformational quantities, in line with recent development of deformation-based seismic assessment. The analytically-derived vulnerability functions are then compared to a data set comprising observational damage data from the Northridge (California 1994) and Hyogo-ken Nanbu (Kobe 1995) earthquakes. The good agreement gives some confidence in the derived formulation that is recommended for use in seismic risk assessment. Furthermore, by varying the dimensions of the prototype bridge used in the study, and the span lengths supported by piers, three more bridges are obtained with different overstrength ratios (ratio of design-to-available base shear). The process of derivation of vulnerability functions is repeated and the ensuing relationships compared. The results point towards the feasibility of deriving scaling factors that may be used to obtain the set of vulnerability functions for a bridge with the knowledge of a 'generic' function and the overstrength ratio. It is demonstrated that this simple procedure gives satisfactory results for the case considered and may be used in the future to facilitate the process of deriving analytical vulnerability functions for classes of bridges once a generic relationship is established.

Damage Distribution of Weak Beam Type Multi-Story Steel Frames By Seismic Response Analysis (지진 응답해석에 의한 보항복형 강구조 다층골조의 손상분포)

  • 오상훈
    • Proceedings of the Earthquake Engineering Society of Korea Conference
    • /
    • 2000.04a
    • /
    • pp.241-248
    • /
    • 2000
  • In order to evaluate the limit earthquake resistance of multi-story steel frames influenced by the strength and stiffness ratios of members a series inelastic response analysis were carried out. From the analysis results the damage distribution rules of multi-story steel frames were proposed. Conclusions are summarized as follows. 1)As the stiffness ratio of beam and column becomes small damage concentrate on the lower end of columns of the first story. 2) Considering the strength and stiffness ratios of beam and column with weak beam type mechanism the equations predicting the damage distribution of multi-story steel frames were proposed.

  • PDF

Corelation of Experimental and Analytical Response of a 1:12 Scale 10-Story Masonry-Infilled R.C. Frame (10층 조적채움 R.C. 골조의 비선형 거동에 대한 해석과 실험의 상관성 연구)

  • 이한선;김정우;김상호
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 1999.10a
    • /
    • pp.487-490
    • /
    • 1999
  • Nowadays, the pushover analysis technique is becoming a very useful tool for the prediction of inelastic behavior of structures in the seismic evaluation of existing buildings in the world. However, the reliability of this analysis method has not been fully checked by the test results. The objective of this study is to verify the correlation between the analytical and experimental response of a high-rise masonry infilled reinforced concrete frame using DRAIN-2DX program and the test results performed previously. This study concludes that the strength and stiffness of members can be predicted with quite high reliability while the ductility capacity of members can not be described reasonably.

  • PDF

Evaluation of Displacement-based Approaches for a Shear Wall Structure (전단벽구조체에 대한 변위기반 내진성능법의 평가)

  • 최상현;현창헌;최강룡;김문수
    • Proceedings of the Computational Structural Engineering Institute Conference
    • /
    • 2003.10a
    • /
    • pp.465-472
    • /
    • 2003
  • In this paper, the displacement-based seismic design approaches are evaluated utilizing shaking-table test data of a 1:3 scaled reinforced concrete (RC) bearing wall structure Provided by IAEA. The maximum responses of the structure are estimated using the two prominent displacement-based approaches, i.e., the capacity spectrum method and the displacement coefficient method, and compared with the measured responses. For comparison purpose, linear and nonlinear time history analyses and response spectrum analysis are also performed. The results indicate that the capacity spectrum method underestimates the response of the structure In inelastic range while the displacement coefficient method yields reasonable values in general.

  • PDF

Lateral-torsional seismic behaviour of plan unsymmetric buildings

  • Tamizharasi, G.;Prasad, A. Meher;Murty, C.V.R.
    • Earthquakes and Structures
    • /
    • v.20 no.3
    • /
    • pp.239-260
    • /
    • 2021
  • Torsional response of buildings is attributed to poor structural configurations in plan, which arises due to two factors - torsional eccentricity and torsional flexibility. Usually, building codes address effects due to the former. This study examines both of these effects. Buildings with torsional eccentricity (e.g., those with large eccentricity) and with torsional flexibility (those with torsional mode as a fundamental mode) demand large deformations of vertical elements resisting lateral loads, especially those along the building perimeter in plan. Lateral-torsional responses are studied of unsymmetrical buildings through elastic and inelastic analyses using idealised single-storey building models (with two degrees of freedom). Displacement demands on vertical elements distributed in plan are non-uniform and sensitive to characteristics of both structure and earthquake ground motion. Limits are proposed to mitigate lateral-torsional effects, which guides in proportioning vertical elements and restricts amplification of lateral displacement in them and to avoid torsional mode as the first mode. Nonlinear static and dynamic analyses of multi-storey buildings are used to validate the limits proposed.

Inelastic Time History Analysis of a 5-Story RC OMRF Considering Inelastic Shear Behavior of Beam-Column Joint (보-기둥 접합부 비탄성 전단거동을 고려한 5층 철근콘크리트 보통모멘트골조의 비탄성 시간이력해석)

  • Kang, Suk-Bong;Kim, Tae-Yong
    • Journal of the Korea Concrete Institute
    • /
    • v.24 no.6
    • /
    • pp.633-641
    • /
    • 2012
  • In this study, the effects of the inelastic shear behavior of beam-column joint on the response of RC OMRF are evaluated in the inelastic time history analysis. For an example, a 5-story structure for site class SB and seismic design category C was designed in accordance with KBC2009. Bending moment-curvature relationship for beam and column was evaluated using fiber model and bending moment-rotation relationship for beam-column joint was calculated using simple and unified joint shear behavior model and moment equilibrium relationship. The hysteretic behavior was simulated using three-parameter model suggested in IDARC program. The inelastic time history analysis with PGA for return period of 2400 years showed that the model with inelastic beam-column joint yielded smaller maximum base shear force but nearly equivalent maximum roof displacement and maximum story drift as those obtained from analysis using rigid joint. The maximum story drift satisfied the criteria of KBC2009. Therefore, the inelastic shear behavior of beam-column joint could be neglected in the structural design.

Accuracy of combination rules and individual effect correlation: MDOF vs SDOF systems

  • Reyes-Salazar, Alfredo;Valenzuela-Beltran, Federico;de, Leon-Escobedo, David;Bojorquez, Eden;Lopez-Barraza, Arturo
    • Steel and Composite Structures
    • /
    • v.12 no.4
    • /
    • pp.353-379
    • /
    • 2012
  • The accuracy of the 30% and SRSS rules, commonly used to estimate the combined response of structures, and some related issues, are studied. For complex systems and earthquake loading, the principal components give the maximum seismic response. Both rules underestimate the axial load by about 10% and the COV of the underestimation is about 20%. Both rules overestimate the base shear by about 10%. The uncertainty in the estimation is much larger for axial load than for base shear, and, for axial load, it is much larger for inelastic than for elastic behavior. The effect of individual components may be highly correlated, not only for normal components, but also for totally uncorrelated components. The rules are not always inaccurate for large values of correlation coefficients of the individual effects, and small values of such coefficients are not always related to an accurate estimation of the response. Only for perfectly uncorrelated harmonic excitations and elastic analysis of SDOF systems, the individual effects of the components are uncorrelated and the rules accurately estimate the combined response. In the general case, the level of underestimation or overestimation depends on the degree of correlation of the components, the type of structural system, the response parameter, the location of the structural member and the level of structural deformation. The codes should be more specific regarding the application of these rules. If the percentage rule is used for MDOF systems and earthquake loading, at least a value of 45% should be used for the combination factor.

Design aspects for minimizing the rotational behavior of setbacks buildings

  • Georgoussis, George K.
    • Earthquakes and Structures
    • /
    • v.10 no.5
    • /
    • pp.1049-1066
    • /
    • 2016
  • An approximate analysis is presented for multi-story setback buildings subjected to ground motions. Setback buildings with mass and stiffness discontinuities are common in modern architecture and quite often they are asymmetric in plan. The proposed analysis provides basic dynamic data (frequencies and peak values of base resultant forces) and furthermore an overview of the building response during a ground excitation. The method is based on the concept of the equivalent single story system, which has been introduced by the author in earlier papers for assessing the response of uniform in height buildings. As basic quantities of the dynamic response of elastic setback buildings can be derived by analyzing simple systems, a structural layout of minimum elastic rotational response can be easily constructed. The behavior of such structural configurations, which is basically translational into the elastic phase, is also examined into the post elastic phase when the strength assignment of the various bents is based on a planar static analysis under a set of lateral forces simulating an equivalent 'seismic loading'. It is demonstrated that the almost concurrent yielding of all resisting elements preserves the translational response, attained at the end of the elastic phase, to the post elastic one.

Analysis of composite frame structures with mixed elements - state of the art

  • Ayoub, Ashraf
    • Structural Engineering and Mechanics
    • /
    • v.41 no.2
    • /
    • pp.157-181
    • /
    • 2012
  • The paper presents a review of the application of the newly proposed mixed finite element model for seismic simulation of different types of composite frame structures. To evaluate the performance of the element, a comparison with displacement-based and force-based models is conducted. The study revealed that the mixed model is superior to the others in terms of both speed of convergence and numerical stability, and is therefore considered the most practical approach for modeling of composite structures. In this model, the element is derived using independent force and displacement shape functions. The nonlinear response of the frame element is based on the section discretization into fibers with uniaxial material models. The interfacial behavior is modeled using an inelastic interface element. Numerical examples to clarify the advantages of the model are presented for the following structural applications: anchored reinforcing bar problems, composite steel-concrete girders with deformable shear connectors, beam on elastic foundation elements, R/C girders strengthened with FRP sheets, R/C beam-columns with bond-slip, and prestressed concrete girders. These studies confirmed that the model represents a major advancement over existing elements in simulating the inelastic behavior of composite structures.