| The reinforced concrete shear walls are mainly used to bear the horizontal load and vertical load caused by wind and earthquake action.It also can effectively prevent the shear failure of structures.The investigation after earthquakes indicates that most reinforced concrete shear walls were destroyed under shear-flexural interaction.Therefore,it is important to study and develop a nonlinear numerical analysis model of shear walls to improve the seismic performance of shear walls.This paper discusses shear wall numerical models in detail.Based on the finite element software OpenSees,the SFI-MVLEM(Shear-Flexural Interaction-Multiple-Vertical-Line-Element-Model)element is performed to establish the nonlinear numerical analysis model of reinforced concrete shear walls.The accuracy of the model is verified by comparing model data with the experimental results.On the basis of the above study,the influence of shear effect on seismic behavior of reinforced concrete shear walls is further studied by variable parameter analysis.The detailed research work of this paper is as follows:1.Based the development of membrane element theory,there are four models expounded,i.e.,Modified compression field theory,Rotating-angle softened-truss model,Fixed-angle softened-truss model,Modified fixed-strut-angle-model.This paper makes a detailed comparison and analysis of the assumptions,coordination and equilibrium conditions of the model and the selection of constitutive,which provides a comprehensive and systematic theoretical basis for the simulation analysis in the following chapters.2.Mechanism of SFI-MVLEM model is discussed in this paper.The element characteristics are introduced in detail,including the assumption of element,element degree of freedom,the calculation of the strain field on RC panel elements,the element stiffness matrix and the element force vector.Meanwhile,reinforced concrete panel behavior is investigated,including the application of Modified fixed-strut-angle-model,modeling of shear resisting mechanism and the selection of constitutive model for reinforcing steel and concrete.3.Based on the SFI-MVLEM model,3 reinforced concrete shear walls with different aspect ratio and 2 reinforced concrete shear walls with different axial compression ratios are simulated and compared with the experimental results.According to the shear displacement of the element,the effect of shear displacement on seismic behavior of reinforced concrete shear wall is further studied.At the same time,the influence of the simulation resutls are analysed with the discretization of elements,dowel stiffness parameter and shear friction coefficient.The parameters were proposed to provide reasonable reference for the follow-up study.4.On the basis of static analysis,the dynamic elasto-plastic analysis of a 5 story reinforced concrete frame shear wall structure is carried out by using the SFI-MVLEM and fiber element.At the same time,a seismic wave is selected and adjusted according to code.Finally,the seismic performance of reinforced concrete frame shear wall structure under different fortification intensities is compared and analyzed.This paper focuses on the research of the development and application of membrane element theory,the SFI-MVLEM element is performed to simulate shear walls and a 5 story reinforced concrete frame shear wall structure.It will also provide references for the further application of the element and the seismic performance analysis. |
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