Study For Ultimate Bearing Capacity Of Continuous Box Model Girder With Transverse Long Cantilever

The PC continuous box girder with transverse long cantilevers is widely applied in urban bridge due to reducing abutment size and its number and increasing clearance under the bridge. At present there is no existent method of studying its ultimate bearing capacity.According to three-span PC box girder of Xi'an city Daxing Road interchange with transverse long cantilevers, a 1/10 scale-down model was designed and casted indoors to study the ultimate bearing capacity of the model bridge. Spatial finite element analysis for the model bridge was carried out adopting ANSYS FEM program under double nonlinearity of material and geometric; damage conformation and ultimate bearing capacity of the modal bridge was studied under different load conditions. Then control mode of ultimate bearing capacity was chosen, and ultimate bearing capacity test under multi-stage loading was carried out. The results of the test show that, under 443kN ultimate load, some cracks appeared in the region of mid-section in the top, bottom slab, web plate of middle span, as well as in the two long cantilevered section and its nearby regions. The cracks were widest in the region of web plate and bottom slab, and the maximum crack width was about 3mm; the largest deflection happened in the mid-section, which was 30.88mm. Annular width crack near the region of load point and shear failure were its' main characteristic. Test data and damage phenomenon was accordance with that of theory analyses, which indicated that analysis method of ultimate bearing capacity on PC box girder with long transverse cantilevers is accurate and reliable.In this paper, a reference was provided for studying on ultimate bearing capacity of the similar box girder with long transverse cantilevers.