The Crack Analysis Of Bottom Plate Of Great Continuous Rigid Frame Bridge And Parameter Research

Along with the rapid development of infrastructure, there are variable cross-section of prestressed concrete continuous rigid frame bridges with its structural rigidity,the good comfort of driving, expansion joints and maintenance simple and so on. It has become one of the major highway bridges. But with the prestressed continuous rigid frame bridge being built in large numbers, particularly the large number of construction of the large-span prestressed continuous rigid frame bridge, also revealed some problems.To the box girder of our great span prestressed continuous rigid frame bridges are carried out research and disease,there are in different degree of cross-Deflection, web and bottom cracking phenomenon and the deterioration of the bridge's operating status. To this end, many large span continuous rigid frame design are increased the number of cross-beam steel floor closure, hoping to improve cross-box in the upper and lower edge of the stress state and the deflection of too large problem. However, a considerable part of the bridge floor beam tension in the fold even after all the tension has not yet appeared when the cross-finished concrete were the problems of the floor down collapse. Therefore, analysis longitudinal cracks reasons on the floor, structural optimization and improvement of transverse stress are necessary.First, the paper surveyed disease situation of collapse which appeared in the continuous rigid frame bridge in china. From the structural design, construction, management and mechanical characteristic of the bridge such as in-depth analysis reasons of the bottom longitudinal cracks, and the corresponding prevention measures.Second, the variations of the bottom curve and thickness have a certain extent influence to transverse stress on bottom slab. This practical project to floor number and floor thickness of the parabolic design variables, other design variables in the conventional constant within reasonable limits, to establish a spatial finite element model for transverse stress floor variation, reasonable parabolic index and the thickness rang of floor, and to study method of the additional floor short rib and transverse prestressing for improving the bottom horizontal stress distribution, as a reference for the structural design of similar projects, maintenance and reinforcement. Finally, in this paper with a engineering background of Ziyang Han River Bridge, the establishment of plane beam element and the spatial finite element model for structural steel in the weight load and prestressed floor beams under lateral loads of stress. And based on the conclusions, optimized floor structure design.