现浇楼板对框架梁端正截面承载力影响的试验研究

Experimental study on influence of cast-in-situ slab on bearing capacity of RC frame beam

通过对近几次地震灾害中框架结构震害调查研究发现,大量框架结构没有实现抗震规范要求的"强柱弱梁"梁铰破坏机制。究其原因主要在于结构设计中并没有考虑现浇楼板对框架梁端正截面承载力的提高作用。为了研究楼板对框架横梁正截面承载力的影响,设计了2个梁板柱节点试件,通过拟静力试验研究了楼板对框架梁正截面承载力的提高作用,纵梁刚度对横梁承载力和挠度的影响,以及楼板参与横梁受力的有效范围。试验与计算结果表明:试验承载力与计算结果吻合良好;考虑楼板配筋可以提高横梁承载力60%左右;楼板参与横梁受力的有效范围是5倍板厚左右;提高纵梁的刚度可以提高横梁正截面承载力和降低挠度。

Based on the investigation about damage of reinforced concrete frame structure in recent earthquake d isa s te r s ,i t shows that a large proportion of frame structures don’t fail in the way of “strong column and weak beam”,which is demanded in seismic design code of buildings. The reason for this phenomenon is that the designers don’t take the enhancement effect of slab for increasing the bearing capacity of beam into consideration. In order to research the enhancement ef fect, two specimens were conducted in this paper. The enhancement effect of slab for bearing capacity of beam, effect of rigidity of lengthways beam on bearing capacity and deflection of lateral beam and the effective region of slab favourable for bearing capacity of beam were researched by quasi-static test. The test and arithmetic result indicate that the results of arithmetic match well with the experiment. Reinforcement of slab can increase the bearing capacity of beam up to 60%. The effective region of slab favourable for bearing capacity of beam is five times the thickness of slab. Increasing the rigidity of lengthways beam can improve the bearing capacity and reduce the deflection of lateral beam.