Two-dimensional Temperature Gradient Effects And Design Methods Of Curved Continuous Box Girder Bridges

With the rapid development of urban roads and highways, curved continuous girderbridges play an increasingly important role in modern traffic. However, in the course ofoperations, disease like excessive radial displacement, bearing hanging in the air and beamflipping often occurs, which threats seriously the safety of service. When designing curvedcontinuous girder bridges, the temperature gradient in “General Standard in the Design ofHighway Bridge and Culvert （JTG D60-2004）” is always used. That is to say, only thevertical temperature gradient is considered. According to the problem that transversetemperature gradient really exists in curved continuous girder bridges in natural environmentbut is not considered when designing curved continuous girder bridges, this paper carries outsome research as follows:1. Based on the needs of analysis of temperature gradient effect, the author discussescauses of temperature gradient and the distribution form of temperature in china’s currentspecifications, and clears the effects and features of temperature gradient loads. Stress anddeformation analysis theories of bridges under temperature gradient loads are summarized.The principles and methods of selecting analysis theories of temperature gradient loads effectsare proposed. The content and methods of this article are determined.2. Based on related research of transverse temperature gradient of bridges, referring totemperature gradient in current specifications of highway bridge, the author constructstwo-dimensional temperature gradient modes depending on the location and trend of bridges.A ramp bridge’s force and deformation under temperature gradient in the specification andtwo-dimensional temperature gradient modes are respectively studied. Through thecomparative analysis of the results, the author discusses characteristics of effect oftwo-dimensional temperature gradient and temperature gradient in specification, and putsforward designing proposals of temperature gradient of curved continuous girder bridges.3. On the basis of two-dimensional temperature gradient effects, the design methods ofsteels and bearing arrangement of curved continuous girder bridges are discussed. Several designs of bearing arrangement are put forward respectively for the whole torsion resistancesupport system and the partial torsion resistance support system. Through comparativeanalysis of the results of the programs, the best designs of bearing arrangement are proposedwhen considering lateral temperature gradient loads.