Analysis Of The Differences Of Elastic Modulus Of Concrete Impact On Deflection In The Mid-span Of The Continuous Rigid-frame Bridge

Continuous rigid frame bridge is a new kind of bridge form in recent decades. This type of bridge form has better spanning ability, lower cost, and it is smoother and more comfortable. However continuous rigid frame bridge has some problems, like box girder beam crack and excessive deflection in the midspan. This article focuses on the relationship between excessive deflection in the midspan and modulus of elasticity of concrete wave. In the actual project, the strength of concrete is strictly controlled. But we always ignore the controling of concrete elastic modulus, and think that when concrete strength meet the regulatory requirements, modulus of elasticity values also reached the design value. But this view is not accurate, because of the different concrete proportion and curing condition, elastic modulus value will changes near the design value. The strength of concrete has meet the design requirements, while the elastic modulus value may still have not reached the reference design. We only control the strength of concrete, don't consider the differences of elastic modulus value, when prestressed tensioning modulus of elasticity values still has not reached the design values. It will cause the concrete creep and the deflection in the midspan of rigid frame bridge both increased.This article has a deep study on the practical project of a bridge in Yunnan province. On the premise of differences between the modulus of elasticity of concrete and design value, using the robust optimization design method research modulus of elasticity of concrete impact on midspan deflection of the continuous rigid frame bridge, and finally finding out the minimum region of sensitive of midspan. In combination with the concrete bridge engineering lab report, this essay analysis on different mix impact on compressive strength, elastic modulus, shrinkage and creep. Ultimately based on robust evaluation of concrete material test data, calculate the cantilever construction of main girder in concrete elastic modulus value when the reasonable interval. Find the right age to provide reference for the actual construction of the project.