钢纤维高强无粘结预应力混凝土扁梁框架抗震性能试验研究

Experimental study on seismic behavior of fiber-reinforced high strength unbond ed prestressed concrete frames with wide beam

本文将钢纤维混凝土技术与无粘结预应力混凝土技术结合用于扁梁框架结构,研究钢纤维对高强无粘结预应力扁梁框架结构抗震性能的影响。通过采用MTS伺服加载系统对三榀具有相同尺寸、配筋和混凝土强度等级,不同钢纤维含量的高强无粘结预应力混凝土扁梁框架进行水平低周反复荷载下的拟静力试验,研究钢纤维对于高强预应力扁梁框架破坏形态、滞回特性、位移延性、耗能能力以及强度和刚度退化等抗震性能指标的影响。研究结果表明,钢纤维不仅可以提高无粘结预应力混凝土扁梁框架的开裂荷载、屈服荷载和极限荷载,改善其破坏形态,还可以有效提高扁梁框架的刚度、延性和耗能能力,从而提高结构的抗震性能,钢纤维可以部分替代扁梁框架节点内箍筋来抵抗剪力。

Experimental study on seismic behavior of three fiber-reinforced hi gh strength unbonded prestressed concrete frames with wide beam under low revers ed cyclic loading was carried out using MTS load systems. They were designed wit h the same size, reinforcement, and strength grade, but different in volume frac tion of steel fibers. Based on the experiments, the effects of steel fibers on t he failure pattern, hysteretic behavior, energy dissipation, displacement ductil ity, strength and rigidity degeneration, etc. have been studied. The results sho wed that the presence of steel fibers has significant effects not only on improv ing the cracking load, yielding load and ultimate load, making better the failur e pattern, but also on enhancing substantially the ductility and energy-absorpt ion property, contributing to reducing the rigidity degeneration, thus improving the seismic resistant behavior of prestressed wide-beam frames. Steel fibers c an be used to partially replace the stirrups as shear reinforcement, suitable re duction of lateral reinforcement in seismic wide-beam-column joints is possibl e with the appropriate application of steel fiber-reinforced concrete.