A Comparative Study Of Cracking Cases In Long Span Continuous Rigid Frame Bridges Box-girder Web

With the quickly development of our transportation and bridge construction, Long Span Bridges especially Long Span PC Continuous Rigid Frame Bridges have come into widespread use in our country owing that in many aspects they can better serve the need of our bridge construction. Continuous Rigid Frame Bridges become the first-choice because of its excellent performance in our bridge constructions. However, with the many use of box girder, many kinds of cracks have become the serious problems and alsofocus in the academic and engineering field. This lead to the reasonable doubt of the applicability of the Continuous Rigid Frame Bridges, and this also suggests that it must have great significances to having a analytical investigation on the cracking reasons of the Continuous Rigid Frame Bridges box girder web. So this paper focuses on the reason analysis of the box-girder web cracks, and futther puts forward some effective precautionary measures and reinforcement measures. 3.Mian researeh works of this paper are included below:(1)The web cracking reasons of Long Span Continuous Rigid Frame Bridges have being analyzed on the Code for design of structures/structure design standard, structure size and calculation method.(2) Based on the comparison of the Long Span Continuous Rigid Frame Bridges at home an aborad on their Macro technical indicators, a qualitative analysis is made for exploring the reason of the great principal tensile stress of the box girder web.In addition,some effective precautionary measures for the great principal tensile stress and active reinforcement measures of the box girder web crack.(3) Because the update cycle of bridge design specification is long, and some contents can't keep up with the development of technology, and the serious ness of overload is underestimation, they all make the brittle reliability of some design section still have some problems. In this paper, we take the Humen Bridge Auxiliary Channel for example, we build up the Plane stem department system by finite elements softwares Midas/civil through loading different norms of automobile loading modes, getting the effect difference between different norms of automobile loading modes, and making a design checking for Humen Birdge tandard. Through analisis, we come to a conclusion that the Bridge Specifications load standards is lower in our country, and we can refer to the foreign standards to check in designing to avoid bridge fault caused by live load. (4) For the web crackings caused by the excessive tensile tress, we put forward some new active reinforcement measures to web cracking.