Research On Strut-and-Tie Method And Its Application In Defective Prestressed Concrete Bridges

With the rapid development of highway of China, the bridge construction has come to a climax period. Long span prestressed concrete constant box girder bridge has acquired wide application home and abroad in recent 20 or 30 years, it has high stiffness to resist torsion, good integration, it can support positive and negative moments, and has mature and easily applied traits. However, many problems have happened on a large number of already built prestressed concrete constant bridges in construction or usage process. The most common and severe defect is the bridge cracking problem, which has seriously affected the normal usage of bridges and become the urgent problem in the engineering field. Since the problem sorts and causes of defective bridges are diverse, in order to analyze the problem cause of defective bridges more effectively, this paper only focus on the deep research on the bridge cracking problem.Strut-and-tie model comes of truss model, and it has a wide application as concrete structure calculation tool in Europe and America. Strut-and-tie model catches hold of the mechanical essence and easy to grasp, its application and development potential are very huge, however, there is few deep research in this field domestically, this paper systematically analyzes the theoretical basis and application situation of this model, and studies the application of this model in prestressed defective bridges.Meantime, combined with the current structure cracking problem existed in bridge projects, it analyzes the basic causes of concrete bridge cracking in detail, provides theoretic references for analyzing the next material bridge.Then it makes parameter identification on prestressed constant bridge with severe defect through random ingestion genetic algorithm, takes advantage of the curved skew bridge program-WXQ modeling to calculate and use the calculation result to analyze force enduring status of defective bridges, and discusses the primary reasons of happed problem.At last, combining the strut-and-tie model and finite element calculation result,...