Study On Creep Law Of Concrete Curved Box Girder Bridge Under Space Temperature Field

In recent years,with the continuous development of urban transportation system towards three-dimensional,concrete curved girder bridge has been widely used in urban overpasses and expressway ramp bridges.However,the concrete curved box girder bridge is exposed to the outdoor environment for a long time.Under the comprehensive influence of solar radiation,daily temperature,wind speed and other factors,there will be large temperature stress and deformation in the structure.Moreover,due to the friction between the bottom of the beam and the support,the residual deformation will accumulate continuously under the action of repeated external forces,which may lead to the occurrence of creep disaster,It seriously affects the safety and durability of the bridge.To solve this problem,this paper takes a concrete curved bridge under construction in Hebei Province as the research object,analyzes its three-dimensional spatial fine temperature field under sunshine,and studies its creep mechanism under spatial circulating temperature field.The main contents of this paper are as follows:(1)This paper systematically expounds the basic theory of sunshine temperature field and three-dimensional shielding theory of the bridge,considers the heat exchange between the air and the inner wall of the closed space of concrete box girder,puts forward a method that can efficiently analyze the fine temperature field of the bridge in the natural environment,and uses FORTRAN language to write the user subroutine for the secondary development of the finite element software ABAQUS,The feasibility of this method is verified by a specific bridge type.(2)Using the simulation method of spatial non-uniform sunshine temperature field of curved beam bridge,taking a concrete curved box girder bridge under construction in Hebei Province as the engineering background and referring to the local meteorological data,the spatial sunshine temperature distribution and temperature time history change of the bridge are simulated and analyzed,The parameter sensitivity analysis of the relevant influencing factors of the spatial sunshine temperature field of the concrete curved box girder bridge is carried out.(3)Based on the analysis of the spatial sunshine fine temperature field of the concrete curved girder bridge,the mechanical model of the curved girder bridge is established.Considering the friction and slip characteristics of the bridge support,the temperature effect of the curved box girder bridge is studied through the sequential "thermal mechanical coupling" analysis method,and the creep mechanism of the concrete curved girder bridge under the spatial cyclic temperature field is studied,Accurately grasp the long-term creep law of curved beam bridge.(4)The factors affecting the creep of curved girder bridges are systematically summarized,and the existing prevention measures of creep diseases are systematically sorted and summarized;A new anti creeping device is designed,and its main structure and realization purpose are described;Finally,the mechanical properties of the device are studied by finite element simulation,and its application in curved beam bridge is discussed.