预应力高强钢丝绳加固桥梁动静态力学性能的测试分析

为了验证预应力高强钢丝绳加固新方法(P-SWR技术)加固工艺的可行性及加固效果的有效性,对某一高速公路上已有较严重损伤混凝土板梁进行了加固与系统测试。给出了P-SWR加固桥梁时钢丝绳数量和张拉控制应力确定,钢丝绳和锚具布置等设计方案以及详细的施工工艺。系统测试了P-SWR加固前后桥梁的动静态力学性能,包括:施工过程中钢丝绳应变、钢丝绳张拉后所加固梁的跨中反拱值,加固前后正常通车时随机汽车动态荷载作用下和部分封闭交通时恒定静载作用下梁的跨中挠度、跨中截面处纵筋应变、跨中截面处板底混凝土应变以及钢丝绳的应变增量等。结果表明,P-SWR加固效果明显,加固后桥梁的极限承载力和正常使用承载力达到规范要求,P-SWR加固技术是一种主动高效式的加固方法,与现有其他加固技术相比优势明显,值得在桥梁等结构加固中大力推广。

Experimental Analysis on Dynamic/Static Mechanical Properties of a Bridge Strengthened with Prestressed High Strength Steel Wire Rope

In order to verify the feasibility and the effect of new prestressed high-strength steel wire rope strengthening technology(P-SWR technology),a seriously deteriorated freeway concrete slab bridge were strengthened and systemic tested.The detailed retrofitting scheme for this bridge was presented.The type and layout of P-SWR,determination of the prestress level and amount of P-SWR,anchorage pattern and construction procedure were introduced.Before and after strengthening,the deflection,longitudinal reinforcement strain and concrete strain at bottom of bridge mid-span were monitored under routine dynamic traffic loading conditions or static loading conditions in case of closed traffic.The strain of P-SWR during construction and mid-span camber deflection after prestressing were also recorded.The results show that the ultimate bearing capacity and service bearing capacity of the retrofitted bridge meet the current code requirement.P-SWR strengthening method is an effective strengthening technique and worth to be promoted in bridge engineering.