端部约束HFR-LWC梁极限承载力研究

Ultimate carrying-capacities of HFR-LWC beam w ith special restrains

将钢筋混凝土梁的特定约束简化为水平刚度和转动刚度,根据受力过程中的几何关系、物理关系和平衡关系,并考虑塑性铰长度的影响,建立了基于面力效应的钢筋混凝土梁极限承载力计算方法。对10根(3根简支、7根特定约束)混杂纤维轻骨料混凝土梁进行四点抗弯试验,分析了支座约束刚度、纤维和配筋率对轻骨料混凝土梁相对承载力的影响规律,结果表明面力效应由支承的水平刚度和转动刚度共同提供,极限抗力对支承转动刚度更为敏感,且考虑面力效应的极限承载力为忽略面力效应的1.5~5.5倍。

The special constrains of reinforced concrete beam are characterized by horizontal stiffness and rotational stiffness.The ultimate carrying-capacities of reinforced concrete beams with membrane actions are obtained based on the geometric equation,physical equation and equilibrium equation,in which the length of plastic hinge is also concerned.Four-point bending tests of LWC beams are conducted,including three simple support beams and seven fixed support beams.The influences of boundary constraint,reinforcement ratio and hybrid fibers on relative load-bearing capacities of the beam are investigated.It is found that membrane actions are acted by the combined effects of horizontal stiffness and rotational stiffness,but it is more sensitive to rotational stiffness,and the ultimate carrying-capacities of LWC beams are 1.5 to 5.5 times compared with that of membrane actions being neglected.