Mechanical Analysis And Structural Optimum Design For Deck Paving Of Long-span Steel Bridge

Streamlined steel box girder and thin asphalt paving have been used popularly by long-span steel bridge to reduce dead loadings and improve the span capacity of the bridge. Because of the special characteristics of the orthotropic deck of steel bridge and characteristics of the asphalt mixture, fatigue failure, rut and swell are always found on the pavement and these destroy severely the performance of steel bridge. Thus it is urgent to do some researches about mechanics and structure design of paving system of long-span steel bridge.Based on the discusses about functions and failures of paving system of long span steel bridge, this dissertation brings forward that the paving system design should think over the characteristics of asphalt mixture, vehicle load grade, traffic size, asphalt pavement thickness, total structural strength, thickness of orthotropic steel bridge deck, dimensions of rib, thickness and distance of the transverse beam et al. Firstly, the tests for asphalt mixture of steel bridge pavement have been done, and based on the result, the appropriate asphalt mixture has been chosen, and the performance of asphalt mixture has been obtained. Secondly, based on the creep test of asphalt mixture, the visco-elastoplastic characteristics of asphalt mixture are modeled, and the failures mechanism of the steel bridge pavement has been analyzed. Based on the result of thermal stress in high way pavement, two-dimensional viscoelastic layered system has been used to analyze the thermal stress of steel bridge pavement. Finally, the FEM is used to analyze the local mechanical characteristics of steel bridge pavement. The distribution of stress, strain and position of limit loading in pavement surfacing are studied. At the same time, sensitivities of asphalt paving have been discussed by changing characters of structure, loading and materials. Thus some conclusions such as limited loadings come into being. Based on mechanical analysis, the structural optimum design for steel bridge pavement system considering the maximum stress on pavement surfacing is discussed from thickness of pavement, thickness steel deck, dimensions of rib, thickness and distance of the transverse beam, and a new pavement system—two-layer pavement is offered. The design theory of long-span steel bridge pavement system in the dissertation is verified by the experimental bridge of Ruenyang Bridge.In a word, researches about mechanics analysis and structure design of long-span steel bridge asphalt pavement system in the dissertation will have a great academic and practical values to construction of the long-span steel bridge pavement system in our country.