波纹钢管加固不同破损程度混凝土管涵试验

为明确波纹钢管加固不同破损程度混凝土管涵的力学性能及机理，采用室内两点加载试验，对波纹钢管加固的未破坏、部分破坏和完全破坏的混凝土管涵进行研究，获得加固管的荷载-位移曲线、破坏特征和截面应变分布，基于破坏特征和截面应变分布假设加固系统为套管体系（Ⅱ类管），根据变形协调条件推导极限承载力的估算公式，并论述套管体系中各个管体的荷载分配机制。研究结果表明：波纹钢管不同程度地提高了混凝土管涵的承载能力和刚度；加固后的复合管为套管体系，荷载分配依据各个管体的环刚度大小，加固管极限承载力的计算值与实测值之间的误差小于10%；只要待加固的混凝土管涵未完全破坏，波纹钢管对钢筋混凝土管的加固效果相近，即部分破坏与未破坏的钢筋混凝土管涵采用波纹钢管加固后的承载能力相近，而完全破坏的钢筋混凝土管涵加固后的承载力较低；填充层不仅起到黏结作用，而且在荷载分配方面起着重要作用；当钢筋混凝土管涵从未破坏到完全破坏时，填充层所分担的荷载迅速增加（由30%增至80%），而波纹钢管分担的载荷仅略有增加（由7%增至18%）；当填充层的刚度从0增加到35 000 MPa时，填充层所分担的荷载从0增加到58%，钢筋混凝土管涵分担的荷载从69%下降到29%，波纹钢管分担的荷载由31%下降到13%。

Experiment on Reinforced Concrete Pipes with Different Deteriorated Levels Rehabilitated with Corrugated Steel Pipes

To investigate the influence of the deterioration levels on the mechanical performance of reinforced concrete pipes (RCPs) rehabilitated with grouted corrugated steel pipes (CSPs), un-deteriorated, partially deteriorated, and fully deteriorated RCPs rehabilitated with CSPs were studied by conducting two-point loading experiments. The load-displacement curves, failure characteristics, and strains were obtained. Then, assuming that the composite system belongs to a "pipe within a pipe system" (type-Ⅱ pipe) based on failure characteristics and strains, the calculation formula for estimating ultimate load-carrying capacity was derived based on deformation compatibility conditions, and the load distribution mechanism for each pipe material was discussed. Research has shown that the load-carrying capacity and stiffness of CSPs are improved by CSPs in varying degrees. As the rehabilitated pipe is a type-Ⅱ pipe, load sharing depends on the ring stiffness of each pipe. The error of the ultimate load-carrying capacity between the calculation and experimental results is less than 10%. The rehabilitated effects are similar as long as the RCPs are not completely damaged, which means that the load-carrying capacity of the un-deteriorated and partially deteriorated RCPs rehabilitated with CSPs are nearly the same, whereas that of the fully deteriorated RCPs rehabilitated with CSPs is low. The grout not only plays a cohesive role, but can also distribute loads. When the RCP is un-deteriorated to completely deteriorated, the load shared by the grout increases rapidly (from 30% to 80%), whereas the load shared by the CSP increases only slightly (from 7% to 18%). When the stiffness of the grout increases from 0 to 35 000 MPa, the load shared by the grout increases from 0% to 58%, the load shared by the RCP decreases from 69% to 29%, and the load shared by CSP decreases from 31% to 13%.