框架-核心筒结构中支承楼面梁的连梁抗震性能研究

Research on seismic performance of coupling beams supporting floor beams in frame-core structures

为得到适用于工程应用的连梁数值模拟方法,基于OpenSees平台提出了一种考虑截面剪切非线性的适用于不同跨高比的钢筋混凝土连梁模拟方法,并通过试验结果验证了模拟方法的准确性。计算了实际工程中连梁承担的集中力取值范围,结果显示楼面梁传递到连梁上的集中力相比连梁自身的受剪承载力较小,通常仅占5%~10%。提出了支承楼面梁的连梁有限元分析模型,并通过对不同跨高比的连梁在不同集中力作用下的低周反复加载数值分析,研究了滞回曲线、刚度退化和耗能能力等抗震性能。结果表明:连梁跨中受集中力后等效刚度减小且减小的比例与集中力大小及加载位移角相关;连梁跨中承受集中力后,随着加载位移角增大,滞回环面积变化比例呈现出先增大后减小的规律;滞回环面积减小比例与集中力大小及加载位移角相关,集中力、加载位移角越大,滞回环面积减小比例越大;总体上,集中力对连梁的能量耗散系数影响不大;当连梁跨中承受的集中力为受剪承载力的10%且加载位移角为4.0%时,等效刚度减小为跨中不受力连梁的82%,滞回环面积减小为跨中不受力连梁的89%,能量耗散系数基本不变。

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 coeficient 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.