Study Of Problem For Concrete Beam Bridge In Construction Period

Beam bridge is oldest, simple and practical, that is dominated by bending. Due to poor mechanical performance, many concrete beam bridges after operating for several years are easily to occur the phenomenon of concrete cracking and excessive midspan sag. The construction method and process control of concrete beam bridge has a great influence on the mechanical performance of using stage. This paper is mainly study on the closure order, loading age and construction loads in the process of construction, which have a great influence on the mechanical performance. The research contents are as follows:1.When the long-span concrete girder bridge is used cantilever construction method, the factors of construction affect the mechanical performance and the structure line shape. The continuous concrete girder bridges in this paper were simplified to the planar member structures, and was analysised on structural cumulative effect of the construction process using the principle of structural mechanics. Meanmile, the construction of 3-span,5-span, 8-span of prestressed concrete continuous girder bridge and 5-span of prestressed concrete continuous rigid frame bridge were simulated by finite element analysis software. The influence of the construction of different closure order to structural performance was analyzed. The different span bridge structures using different construction methods were found having different mechanical behavior and different structural linetype, and were summarized the principles of the mechanical behavior and structural linetype, when the bridges with different span were used different closure order.2. In this paper age-adjusted effective modulus was used to substitute for concrete elastic modular to consider the shrinkage and creep influences of concrete. Combining age-adjusted effective modulus method with finite-element method, finite-element step-by-step analysis method was studied to analysis the effect of the mechanical behavior and structural linetype when loading age was changed.3. This paper according to construction machinery and construction machinery load level using in the construction process of small and medium-sized span concrete girder bridge, analysises that the effect of the mechanical performance on construction loads using in the construction process of small and medium-sized span concrete girder bridge,and summarizes the attention problems during the construction process of small and medium-sized span concrete beam bridge.