活性粉末混凝土梁受弯非线性全过程分析

Nonlinear Full-Range Flexural Analysis of Reactive Powder Concrete Beams

采用活性粉末混凝土(RPC)材料的单轴拉压应力—应变关系,考虑RPC梁受力特性,以平截面假定及数值积分法为基础,根据内力平衡关系编制RPC梁的截面计算分析程序,计算其弯矩—曲率关系曲线。在此基础上利用共轭梁法,进一步得出RPC梁的荷载—挠度关系曲线,获得任意一级加载后的任意节点的位移,从而达到对RPC梁进行全过程分析的目的。用7组RPC梁的三分点破坏加载试验对数值计算结果进行验证,试验结果表明:RPC梁受力全过程中平截面假定仍然适用,数值计算出的配筋PRC梁的荷载—挠度全曲线、破坏形态以及极限荷载与试验结果吻合良好;无筋RPC梁试验结果均小于理论计算结果,且相差较大,无筋RPC梁的最终破坏模式为单一裂缝的脆性破坏。建议设计RPC梁时,在受拉区配置一定量的抗裂分布钢筋。

Based on the plane-section assumption and the method of numerical integration, an analysis program is developed to reveal the mechanical behavior of RPC flexural beams section, which can be used to calculate the curves of moment-curvature relationships of RPC beams. In this program, the uniaxial tension-compression stress-strain relationships of RPC material and the mechanical characteristics of RPC beams are considered. The load-deflection relationships are gained with the method of conjugate beam. The displacements of all nodes are obtained under every steps loading so as to achieve the full-range flexural analysis of PRC beams. Seven beams are tested in three-point bending apparatus to testify the results of numerical calculation. It is shown that the plane-section assumption is applicable during the full-range deformation process. The load-deflection relationships, the failure mode and the ultimate load got from the program are in accordance with experimental results of RPC beams with steel bar, while the results of numerical calculation of RPC beams without steel bar are much less than the corresponding experimental resuits. It is observed that the failure modes of RPC beams without steel bar are brittle fracture with one crack, and suggested that the anti-crack distributing steel bars should be arranged in the tension side of RPC beams.