The Research For Void Mechanism And Detection Method Of Steel-concrete Composite Section In Railway Cable-stayed Bridge

Steel-concrete composite section structure is widely used in various kinds of cable-stayed bridges with the constant development of domestic bridge engineering technology. The structure is a new kind based on the steel and concrete structure as it cleverly applies the compressive property of concrete and tensile property of steel together. The collaboration capacity of these two structures plays key role in the cable-stayed bridges. Practice indicates that steel-concrete composite section may engender local void under the construction process and the fatigue effects from live train loads. This phenomenon may diminish the working life of this composite structure to a certain extent and greatly affect the carrying capacity of the whole structure. So it should not be ignored as it may lead to the damage of structure and even the dangerous accident. For now, there are few documents on the research of local void damage of steel-concrete composite section. First of all, this paper builds the finite element model with the ANSYS software to analyze that if its mechanical deformation meets the design requirements under the static loads. Second, it does research on the void mechanism during construction process and the long-term operation of structure depending on the various void influencing factors, and then kills the concrete elements of void area by using the relationship between finite birth and death to simulate the void damage. At last, according to the features of steel-concrete composite section and the void mechanism, this paper analyzes the applicability of the existed void detection technology and advances a new kind of void detection method which is more targeted for Steel-concrete composite section structure.