混凝土箱梁大悬臂模型桥极限状态试验研究

Non Linear Analysis of Transverse Long Cantilever for Continuous Box Girder on Model Bridge

以某实桥联混凝土箱梁横向大悬臂为原型,根据相似原理,建立模型非线性准则,设计制作了1∶10缩尺模型.研究了混凝土箱梁大悬臂模型桥的极限状态受力性能和变形、破坏形态、破坏机制、裂缝宽度及发展规律.研究表明:集中荷载作用在跨中,模型桥承载力达到极限状态时,荷载作用处变形相对其他部位较大;集中荷载作用在大悬臂横梁两端,横梁上缘顶板顺桥向开裂长度过大,裂缝过宽而导致模型桥极限承载能力下降;由于混凝土箱梁大悬臂模型桥宽跨比较大,双向受力明显,最终表现为局部承载.

Limit state tests are conducted on a 1 ： 10 scaled model of transverse long cantilever concrete box girder in Xi＇an to investigate the failure mode,failure mechanism and shape,deflection, variation of crack propagation such as crack width and length. Meanwhile, model nonlinear criterion is presented. Experimental results indicate that while concentrated loads acting on mid-span approach to limit state the deflection near the load location is bigger than other＇s, crack is distributed ovally as the loads center of a circle, the structure fails when the crack on concrete at web plate is cut through; Concentrating loads acting on the transverse sides of long cantilever beam will lead to cracks length and width on the upper plate big, which it cause the limited bearing capacity low; because of the ratio of width to length is large, hi-direction stress is obvious, which shown as the partial bearing capacity finally.