Research on seismic performance of coupling beams supporting floor beams in frame-core structures
In order to obtain a numerical simulation method for coupling beams suitable for engineering applications,a modeling method for reinforced concrete coupling beams suitable for different span-to-height ratios that considering cross-section shear nonlinearity was proposed based on the OpenSees platform,and the simulation method was verified through test results.The value range of the concentrated force borne by coupling beams in actual engineering was calculated.The results show that the concentrated force transmitted from floor beams to coupling beams is smaller than the shear bearing capacity of coupling beams themselves,usually only accounting for 5％to 10％.A finite element analysis model of coupling beams supporting floor beams was proposed,and the hysteretic curves,stiffness degradation,energy dissipation capacity were studied through numerical analysis of low-cycle repeated loading of coupling beams with different span-to-height ratios under different concentrated forces.The results show that the equivalent stiffness of the coupling beam decreases after being subjected to concentrated force in the mid-span,and the reduction rate is related to the concentrated force and the loading displacement angle.After the coupling beam is subjected to concentrated force in the mid-span,as the loading displacement angle increases,the change rate of the hysteresis loop area shows a pattern of first increasing and then decreasing.The reduction rate of the hysteresis loop area is related to the concentration force and the loading displacement angle.The greater the concentration force and the loading displacement angle,the greater the reduction rate of the hysteresis loop area.In general,the concentration force has little effect on the energy dissipation coefficient of the coupling beam.When the coupling beam bears a concentrated force which is 10％of the shear capacity at the middle span and the loading displacement angle is 4.0％,the equivalent stiffness is reduced to 82％of the mid-span unstressed coupling beam,and the hysteresis loop area is reduced to 89％of the mid-span unstressed coupling beam,and the energy dissipation coefficient remains basically unchanged.
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