角钢格构混凝土组合梁受弯性能研究

Research on bending behavior of angle steel lattice concrete composite beam

为研究角钢格构混凝土组合梁的受弯性能,开展了四点弯曲试验及有限元模拟研究,并基于平衡条件推导正截面受弯承载力计算式,提出了相关设计建议。研究结果表明:纯弯段布置缀条可有效限制受压区角钢的屈曲失稳破坏;试验中受拉区配钢相同的对称配钢组合梁与非对称配钢组合梁相比,受弯承载力提高约10%,延性也有不同程度的提升。因此在经济合理的范围内,推荐使用对称配钢的角钢格构混凝土组合梁;增大配钢率可提高对称配钢角钢格构混凝土组合梁的受弯承载力,配钢率从3.94%提高至5.58%时,对称配钢组合梁的受弯承载力提高约20%;此外,角钢格构混凝土组合梁的受弯变形满足平截面假定;对于对称配钢的角钢格构混凝土组合梁,其角钢骨架对核心区混凝土的约束作用不可忽略,可根据Mander模型计算混凝土的强度提高系数,或简化的取1.2。

In order to investigate the flexural behavior of angle steel lattice concrete composite beam,four-point bending tests and finite element simulation studies were conducted.Based on the equilibrium conditions,a formula for calculating the flexural capacity was derived.Relevant design suggestions were also proposed.The results indicate that the arrangement of batten plates can effectively restrain the buckling instability and failure of the compressed angle steels.Compared with asymmetrical angle steel lattice concrete composite beams,the ultimate flexural capacity of symmetrical angle steel lattice concrete composite beams increased by approximately 10%,and there was also an improvement in ductility.Therefore,it is recommended to use symmetrical angle steel composite beams within the reasonable economical range.Increasing the angle steel ratio can improve the flexural capacity of symmetrical angle steel lattice concrete composite beams.When the angle steel ratio increased from 3.94%to 5.58%,the flexural capacity of the symmetrical composite beams increased by approximately 20%.Additionally,the bending deformation of the angle steel lattice concrete composite beam conforms to the assumption of plane section remains plane.For the symmetrical angle steel lattice concrete composite beam,the restraining effect of the angle steel skeleton on the core area concrete cannot be ignored,and the confined strength ratio of the concrete can be calculated according to the Mander model,or it can be simplified as 1.2.