支座约束对拱效应下框架梁极限承载力的影响

Influence of support constraint on ultimate bearing capacity of flame beam under arching action

通过对5根截面尺寸和配筋相同,但支座约束不同的试验梁进行跨中加竖向集中力的试验,研究了支座约束对拱效应下钢筋混凝土框架梁极限承载力的影响。试验研究和理论分析表明,施加端部约束的框架梁存在着拱效应,使框架梁的极限承载能力有显著的提高。随着支座刚度(包括水平约束刚度和转动约束刚度)的增大,梁的跨中极限承载力也随之增大,承载力可以提高30%以上。当相对水平约束刚度δ>1时,承载力的提高就变得缓慢,因此建议在实际工程设计中取δ=1,这样既经济又合理。

This article designs 5 reinforced concrete beams which have the same cross-section dimension and steel bar, the end of beam is fixed on steel supports with different constraint. The load is acted on the middle of beam span. In this way, we researched the limit bearing capacity of the beam under different support eanstraint. In the experiment, the stiffness of the support was different under altering support constraint. The experiments show that, arching action of the beam has relationship with the support constraint; the stiffness of the support can influence the limit load of the beam. The limit load is higher when support stiffness is harder, but when the relative horizontal constraint stiffness 8 is higher than 1, the enhancement of the bearing capacity is not clear.