预应力高强钢丝绳抗弯加固钢筋混凝土梁的试验研究

提出一种预应力高强钢丝绳抗弯加固混凝土结构的新方法(简称P-SWR加固技术)。介绍这种新技术的提出思想及实现工艺,对预应力高强钢丝绳抗弯加固混凝土梁进行试验研究,重点讨论直接加载、先损伤后加载、钢丝绳层数、钢丝绳与混凝土黏结性能、锚固方式等参数对加固性能的影响,并与粘贴CFRP和钢板加固混凝土梁性能作了比较。试验结果表明,预应力高强钢丝绳加固能同时显著提高混凝土梁的开裂荷载、截面刚度、屈服荷载、最大承载力,加固后的梁发生钢筋屈服、受压区混凝土压坏、钢丝绳断裂的延性破坏,能有效限制混凝土裂缝宽度,钢丝绳能达到极限拉伸应变而充分发挥作用。P-SWR加固技术可较好地解决现有加固方法中的诸多缺点,是一种高效主动式的加固技术。另外,该技术还具有易施工、耐火、耐老化、成本低等优点,值得在实际工程中大力推广应用。

Experimental study on flexural strengthening of RC beams with prestressed high strength steel wire ropes

An innovative technique for increasing the flexural capacity of concrete structures by using prestressed high strength steel wire ropes(P-SWR strengthening technique)is presented.The key features and the construction procedure are also introduced.The flexural behaviors of different RC beams strengthened with P-SWR are studied.The influence parameters,including the loading method(direct loading or pre-damaged loading),the layers of steel wire rope,the bonding or un-bonding between the steel wire and concrete,and the types of anchorage,are discussed.Test results are compared with those for other identical concrete beams strengthened with CFRP(carbon fiber reintorced polymer)composites and steel plates.Test results indicate that the P-SWR could significantly improve the cracking load, stiffness,yield load and maximum flexural capacity of RC beams.The failure model for the beams strengthened with P-SWR has the typical characteristics,such as steel yielding,crushing of concrete and the fracture of steel wire ropes. The width of flexural cracks in concrete beams is effectively controlled.This method can also exploit the strain capacity of the wire rope to its maximum.Due to its feasibility for field installation,superiority for fire and corrosion resistance, and low cost,the presented method offers an alternative and more attractive way to existing strengthening methods.