| Hybrid structure is composed of steel frame (or steel reinforced concrete or concrete-filled steel tube frame) and reinforced concrete tube (or steel reinforced concrete tube), with the increase of the building height, need to set the strengthened layer (general for the outrigger truss), the structure of this system is more and more used in high-rise and super high-rise buildings, but the study of this kind structural system under the action of seismic response are not deep enough, have problems of the theory behind the practice. According to the Lanzhou Red Mansions Times Square Building as the research background (a typical Structural system of framework-core tube-outrigger trusses strengthened layer), study on the seismic performance and shaking table test of this kind of structure system, the completion of the work and the main results achieved are as follows:(1) Summarized the test results of steel reinforced concrete shear wall at home and abroad, the destruction of steel reinforced concrete shear wall is divided into three stages, theoretical to experimental data regression correction, get the skeleton curve of steel reinforced concrete shear walls. Finally, based on the test results proposed the restoring force model of four polyline considering stiffness degradation with designated point type.This restoring force model’s calculation parameters have clearly physical meaning, easy to computer programmed, it can provide certain reference for the elastic-plastic dynamic analysis of the structure with the steel reinforced concrete shear wall. Using fiber unit in program of OpenSEES, consider the impact of shearing at the same time, the steel reinforced concrete shear walls hysteretic behavior are analyzed under horizontal reciprocating loads. This article hysteretic model, fiber model calculated value and test data are compare together, the results shows that the degree of agreement of the three is good, prove that the reliability of the restoring force model proposed in this paper.(2) From the level of cross-section of the steel square tubular column, combine with the test results, the destruction of steel square tubular column is divided into two stages, derivation the skeleton curve of the components, obtained three line hysteretic model of concrete-filled steel tube column. Finally, using the fiber beam-column element in OpenSEES program, the steel square tubular column hysteretic behaviors are analyzed under horizontal reciprocating loads. This article hysteretic model, fiber model calculated value and test data are compare together, the results shows that the degree of agreement of the three is good, prove that the reliability of the restoring force model proposed in this paper.(3) Through the stress mechanism analysis of the outrigger truss strengthened layer, take the reinforced layer model simplified as cantilevered latticed steel columns model. Take vertex displacement of the structure as the control indicators, analysis changes in bending stiffness of outrigger beam and axial stiffness of the truss web impact on lateral displacement of the structure. Proposed quantitative indicators by outrigger beam bending stiffness and shear wall bending stiffness ratio α, truss web axial stiffness and the frame column axial stiffness ratio β. Finally, through the two projects, obtains that linear stiffness ratio a of one outrigger truss strengthened layer optimum range is0.25to1.0, linear stiffness ratio β optimum range is1.0to4.0; linear stiffness ratio a of two outrigger trusses strengthened layer optimum range is0.25to1.0, linear stiffness ratio β optimum range is1.0to3.0; For the two outrigger trusses strengthened layer structure, increase the lower part of the strengthened layer outrigger beam’s bending stiffness to increases the effect of resistance to lateral of the structure than increase the upper.(4) Through the static elastic-plastic analysis and dynamic elastic-plastic analysis principle and method of research, find out the problems of the two kinds analysis method, and static elastic-plastic analysis single modal pushover analysis to do an improved, derivation of a multi-modal pushover analysis method. Take advantage of the project of this paper’s research background, respectively for the static and dynamic elastic-plastic analysis. Comparative analysis of the structure of different loading patterns, the results are quite different; Proposed that practical engineering design should adopt a variety of loading patterns to synthetic discriminant; Multi-modal pushover analysis considering the impact of higher modes, higher modes who dominant the structure should adopt a multi-modal pushover analysis method; In the structural dynamic elastoplastic analysis, can get the elastic and plastic deformation of the structure under the rare earthquake, but the influence of the selected seismic wave is relatively large, need to combined with the static elastoplastic analysis’s result make a comprehensive judgment on the seismic performance.(5) Take Lanzhou Red Mansions Times Square as the prototype, a shaking table model test of the1:25scale models to carried out, the acceleration of the test similar ratio is1.6:1, model structure experienced a series of earthquake equivalent to8degrees of small earthquake to8degrees of large earthquake one-way and two-way earthquake ground motion input, obtained the law of interlayer displacement, acceleration, interlayer shear force distribution of the structure under the effect of the intensity of earthquake. Comparative analysis by finite element software simulation and test results, analysis and summary the phenomenon of the structure in the test, find out the reasons of the various phenomena. Combined with software calculation results, the weak parts of the structure were comprehensive judgment and give the corresponding strengthening measures at the same time, can provide a reference for the design and application of this kind of structure system in high intensity area. |
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