某无粘结预应力混凝土箱型梁的承载力分析

ANALYSIS ON THE BEARING CAPACITY OF AN UNBONDED PRESTRESSED CONCRETE BOX GIRDER

为正确评价某立交桥的承载能力,对其中的一跨无粘结预应力混凝土箱型梁进行了现场静载试验。建立了梁的有限元计算模型并基于静载试验结果验证了模型的正确性,论证了利用该模型对梁进行弹塑性全过程分析的可行性。然后模拟了构件在不同荷载作用下加载直到破坏的全过程。得到了梁的荷载-挠度曲线、荷载-预应力增量曲线以及开裂荷载、极限荷载等,为立交桥承载能力的评定提供了参考依据。

In order to evaluate correctly the bearing capacity of one grade separation bridge,the field static load test of an unbonded prestressed concrete box girder in the bridge was carried out.A finite element calculated model for this box girder was established and the model proved effective based on the static load test results,the feasibility of taking the full-range elasto-plastic analysis of the box girder by using this model was demonstrated.Then this member was simulated for the whole process of loading until failure under different loading sequences,the curves of load-deflection and load-stress increment of pre-stressed tendon as well as the cracking load and ultimate load of the box girder were obtained,which provide the reference basis for the evaluation of the bearing capacity of this grade separation bridge.