| The complex mechanical behavior and numerical models of the conventional reinforced concrete(RC)coupling beams and steel coupling beams have significant influence on the accurate and efficient seismic analysis of high-rise frame-core structural systems.This dissertation thus focuses on the two typical kinds of coupling beams.The mechanism,numerical models and the application in the structural system are investigated in detail.The main research results are as follows:(1)An accurate numerical model with high efficiency for the conventional RC coupling beam is proposed and developed.The nonlinear shear force-shear deformation and shear force-shear sliding relationships are proposed.By incorporating the nonlinear shear effects into the conventional fiber beam-column element,an accurate,efficient and convenient FEA element for RC coupling beams are developed on the platform of general FEA package MSC.Marc(2007r1).The accuracy and numerical stability are verified by a large number of test data and the formulas for critical parameters such as shear capacity,stiffness after diagonal cracking and the shear limit curves are compared and discussed.(2)An accurate numerical model with high efficiency for the steel coupling beam is proposed and developed.By incorporating the shear strain of fibers and two-dimentional constitutive models into the conventional fiber beam-column element,an FEA element for steel coupling beams that can consider the shear deformation,yielding and hardening,is developed on the platform of MSC.Marc(2007r1).The accuracy is verified by results of various experiments.The calculation efficiency of the element is proved to be improved by 5-6 times compared to the fine shell element.(3)The two coupling beam elements are integrated into the static numerical model of coupled shear wall system and the influences of coupling beam on the system behavior are analyzed.Based on the developed coupling beam element together with the multi-layer shell element and conventional fiber beam-column element,a new coupled shear wall model is proposed.The accuracy of the model is verified by test results of various coupled wall specimens.The influences of different failure modes,deformation types and element mesh strategies on the system behavior are revealed.(4)The two coupling beam elements are integrated into the dynamic numerical model of frame-core tube system and the seismic responses of coupling beams are investigated.The proposed coupled shear wall model is applied to the seismic analysis of RC core tubes and frame-core tubes.The distribution and evolution of the shear force and deformation of coupling beams under seismic excitation are revealed.The accuracy of the model is verified by shaking table test results.The calculation time consumed is also proved to be reduced by 30%-50% compared to the model with multi-layer shell element.The developed fiber beam-column element considering the nonlinear shear effect and the proposed numerical model for coupled shear wall and frame-core tube system have provided a powerful tool for the further research on the seismic catastrophe performance of high-rise structural systems. |
