Temperature Effect Analysis Of Long-span Continuous Rigid Frame Bridge

With the rapid development of traffic construction in our country, long-span prestressed concrete continuous rigid frame bridge has been widely used in our country for the advantages of great spanning capacity, reasonable force, good overall, beautiful modeling etcetera, and smoothly driving. At the same time, it also accompanied with some problems, such as temperature stress or temperature deformation gets large, the pier top horizontal displacement overruns and generates temperature cracks.This paper bases on the engineering background of Secondary Navigable Spans of Suzhou-Nantong Yangtze River Bridge, and builds the finite element model of this bridge in Midas/Civil software, and based on it, the paper mainly does the following work:Firstly, this paper systematically introduces the formation, classification and characteristics of the temperature load, the internal and external factors that affects the temperature distribution, and then expounds the domestic and foreign typical bridge design standard about the rules of the temperature loads and the temperature stress calculation formula of Chinese bridge criterion.Secondly, respectively use the bridge design modes of temperature load pattern of Britain, New Zealand, China highway and railway and Japan, load the vertical sunshine temperature gradient on the box girder, calculate and analyze the distribution regularity of stress and deformation of the box girder, and research the change trend and rule of the sunshine warming stress and deformation with box girder height-span ratio and the thickness of web. Results show that the selection of temperature gradient curve has a great influence on the temperature stress and displacement of continuous rigid-frame box girder, at the same time the temperature stress calculation of long-span continuous rigid frame bridge can’t ignore the influence of transverse temperature difference, and we should pay attention to the box girder tensile stress caused by the sunshine temperature gradient and appropriately consider the temperature difference of the depth and beradth of box girder in engineering design.Thirdly, according to the current theory of bridge design theory of temperature gradient, apply different direction of sunshine heating load on the hollow thin-wall piers, calculate and analyze the distribution regularity of stress and deformation of the hollow thin-wall piers, and its affection on stress and deformation of the box girder, and research the change trend and rule of the sunshine warming stress and deformation with the width and center dance along the hollow thin-wall piers. Results show that the thin-wall piers would produce large temperature stress and indispensable torsion deflection under sunshine heating load, but it has little impact on the stress and displacement of the box girder.Fourthly, Thought put forward the continuous rigid frame bridge thin-walled pier push stiffness calculation scheme, deduce the anti-pushing stiffness practical calculation formula of the single and double thin-wall piers of the continuous rigid-frame bridge and calculate the push stiffness ratio, the results show that the anti-pushing stiffness practical calculation formula of the thin-wall pier is decided on the thin-walled pier and girder bending stiffness ratio(i.e. the pier beam stiffness ratio) and boundary conditions of the whole bridge, and get the change trend of the anti-pushing stiffness ratio of the single and double thin-wall piers with high pier and pier spacing changes. And through calculation and analysis of the temperature difference effect of the whole bridge, deduce the structural internal force calculation formula of the continuous rigid-frame bridge in year temperature difference load, and the continuous rigid frame bridge temperature internal force simply calculation formula with the change in the high and pier spacing of pier, and get the change trend and rule of the continuous rigid frame bridge year temperature internal force and deformation with high pier and pier spacing changes.