Flexural behavior of ultra-high performance concrete joint without formwork in prefabricated small box girder bridges
In order to improve the crack resistance of wet joints in prefabricated small box girder Bridges and simplify the site construction process,a construction form and design method of UHPC wet joint without formwork was proposed and its bending resistance was studied.Based on the assumption of flat section,the condition of cross-section equilibrium,the constitutive relation of steel bar,UHPC and concrete,a method for calculating the flexural capacity of the UHPC-NC composite section considering the contribution of UHPC in the tensile zone was proposed.The calculated value of the formula was compared with the finite element calculation.Based on the design method of UHPC wet joint without formwork,the feasible values of each parameter under the section form were obtained,and the functional relationship between the width of the wet joint rectangle strip and the calculated span of the small box girder bridge panel was obtained by fitting.Meanwhile,based on the finite element method,the numerical model of UHPC wet joint without formwork was established,the influence of the structure form of wet joint and the width of wet joint on the flexural capacity of UHPC wet joint was analyzed.The results show that the calculated value of the formula and the finite element calculation are in good agreement,which can provide guidance for the design of wet joints.The wet joint without formwork can give full play to the excellent mechanical properties of UHPC,inhibit the development of cracks,improve the durability and bearing capacity of bridge deck,and speed up the construction efficiency.The minimum width of the wet joint without support mold is 140 mm at the condition of the transverse steel bar diameter of the small box girder bridge is 16 mm,and the construction performance and economic performance of the precast bridge panel can be played.
万方数据
维普
