Buckling Analysis And Research Of Steel-Concrete Composite Box Girder Bridge With Corrugated Steel Webs

Corrugated steel web（CSW）composite box girder bridges are a new type of bridge;they are fabricated with steel-concrete composite structures that use CSWs instead of concrete webs.This type of bridge capitalizes on the advantages of both steel and concrete,enhancing the resistance of the bridge to structural stresses.Because of its structural characteristics,composite box girder Bridges with CSWs have been widely designed and applied in recent years.With the increase of bridge span and the application of this bridge type in urban Bridges,variable-section CSWs and curved CSWs composite box girder bridge are increasingly used.In this paper,the buckling stability of the composite box girder bridge with variable-section and curved CSWs is analyzed and studied by means of ANSYS finite element（FE）numerical simulation and theoretical analysis.The main research contents are as follows:（1）Taking the Nanzhao Huaihe Bridge as the engineering background,the corresponding finite element models（FEM）of prismatic CSWs and variable-section CSWs were established.By comparing the FE results of the prismatic CSWs with variable-section CSWs,it is found that there is a specific relationship between them.Finally,based on this relationship and the existing theoretical calculation formula of shear buckling strength of prismatic CSWs,a new shear buckling strength formula is proposed for calculating the shear buckling strength of variable-section CSWs.The results calculated using the proposed formula for a variable-section CSW exhibited good agreement with the FEA results.The differences in the shear strengths of different types of variable-sections CSWs were within5%under simple and fixed boundary conditions.（2）This study demonstrates that the existing formula for calculating the shear buckling strength of prismatic CSWs is inapplicable when the web height exceeds 4 m.An alternative formula that can calculate the shear buckling strength of prismatic CSWs when the web height exceeds 4 m is presented and verified to have good accuracy.（3）The influence parameters that may affect the shear buckling strength of variable-section CSWs are studied.The main influencing parameters are as follows:different types of CSWs,the corrugation depth-to-web thickness ratio（h_r/t_w）,the web flat-panel width-to-depth ratio(b/h_w2),web slenderness(h_w2/t_w).Finally,the variation rule of the influence parameters on the shear buckling strength of variable-section CSWs is summarized.（4）Basing on the large deflection theory of thin plate,combined with Galerkin method and the principle of virtual displacement,the theoretical formula of calculating the Global shear buckling strength of curved CSWs with the simple supports condition was derived.Also,the ANSYS FEM was established to verify the formula.The results show that the theoretical calculation formula has good calculation accuracy,and the error is less than 10%.（5）The influence parameters of the shear strength of the curved CSWs,such as the corrugation depth-to-web thickness ratio,web slenderness,the model of the corrugated steel webs and the curvature radius of the curved CSWs were studied.Finally,the variation rule of the influence parameters on the shear buckling strength of curved CSWs is summarized.