负弯矩作用下蜂窝组合梁的承载力

Experimental Study on the Bending Capacity of Castellated Composite Beam Under Negative Moment

蜂窝组合梁能降低建筑层高,为了研究蜂窝组合梁负弯矩区段承载力,设计了两个蜂窝组合梁试件,并进行了静力加载试验,研究了扩张比、第一洞口间距对蜂窝组合梁的强度、刚度和破坏模式的影响.试验结果表明:对于扩张比小于1.3的试件,蜂窝组合梁在近支座截面或第一洞口中心截面发生弯曲破坏;在扩张比给定的情况下,蜂窝组合梁的第一洞口间距主要影响蜂窝组合梁的破坏模式;当近支座截面和第一洞口截面同时为蜂窝组合梁的破坏控制截面时,钢梁扩张比对蜂窝组合梁的强度与刚度影响较大.在试验研究的基础上提出了近支座截面的名义抗弯承载力计算方法,该方法同时考虑了构件的破坏模式与两个控制截面的抗弯承载力,公式计算值与试验值吻合.

Castellated composite beam can decrease the floor height of buildings.In order to investigate the bending capacity of castellated composite beam under negative moment,two cantilever beam specimens were designed and tested by applying static loads.The influences of the expansion ratio and location of first web opening on beam mechanical behavior were studied.The results show that bending failures of the specimens occur near the beam support section or the first web opening section for the specimens with the expansion ratio no larger than 1.3.When the expansion ratio of specimens is maintained unchanged,the location of the first web opening mainly affects on the failure mode of the beam.For both the beam support section and the first web opening section being the strength control section,the expansion ratio of specimens have greatly effect on the strength and stiffness of the beam.Considering both the failure modes and the flexural capacity of two control sections,the method calculating the nominal bending capacity of the castellated composite beam near the support section were presented,and the calculated va-lues fit well with the experimental ones.