Robustness Analysis Of Half-through Arch Bridge Based On Ultimate Load-carrying Capacity

In the field of civil engineering,structural robustness refers to the ability of a structure to resist disproportionate destruction in the event of local damage.At present,more and more bridge collapses are caused by local damages,how to enhance the robustness of the structure and how to improve the ability of the structure to tolerate damage under extreme conditions has drawn widely attention from academy and engineering.In this paper,based on the engineering background of Yuan Ze Bridge in Wuhu,the full-bridge finite element model is established,The robustness index based on the ultimate load-carrying capacity is proposed to analyze the robustness of the bridge,and a variety of damage scenarios are considered synthetically based on actual conditions.By analyzing the structural robustness of the bridge can predict the resistance to destruction because of local damage,with practical engineering significance.The main research work and conclusions of this paper are as follows:1.Based on the engineering background of Yuan Ze Bridge in Wuhu,a full-bridge finite element model is established.Through the static analysis of the bridge,the cable force,internal force distribution and structural deformation of the structure are clarified.Then,the basic theory of nonlinear and the solving method of nonlinear equations are studied.The ultimate load-carrying capacity of the structure is calculated by considering the double nonlinear effect of geometric nonlinearity and material nonlinearity.Through the analysis of the loading process,the yield process and failure path of the structure are defined,and the ultimate failure mode of the structure is the booms’ broken.2.Robustness analysis of Yuan Ze Bridge is based on the ultimate load-carrying capacity of the bridge.Meanwhile,based on the structural displacement,the tensile stress of the booms,the equivalent stress of the main beam and the the main arch strain energy are considered.Considering the damage of the boom,the damage of the arch rib,the damage of the longitudinal beam and the damage of the transverse beam respectively,the quantitative results and the variation regularity of the structural robustness are considered.The results show that the failure of a single boom has little effect on the overall structure and the simultaneous failure of three or more suspenders has a significant impact on the ultimate load-carrying capacity of the structure.The damage of the arch rib and the stringers greatly affects the structure and should be given sufficient attention.The damage of transverse beam has little effect on the structure.3.The main factors influencing the structural robustness of Yuan Ze Bridge are analyzed by parametric analysis,and the influence of different boom forms,beam arrangement spacing,arch yield strength and longitudinal / transverse beam yield strength on structural robustness are analyzed.The analysis results show that: the structure of the booms has the most significant impact on the robustness of the arch bridge.The reasonable boom form can not only greatly increase the ultimate bearing capacity of the arch bridge,but also improve the robustness of the arch bridge.Increasing the number of beams can improve the integrity and redundancy of the entire bridge structure and also help to improve the robustness of the structure.The robustness of the arch bridge structure is closely related to the yield strength of the arch rib.To improve the robustness of the arch bridge by increasing the yield strength of the arch rib can obtain better results.There is no direct connection between the robustness of the arch bridge structure and the yield strength of the longitudinal/cross beam.It is not useful to increase the robustness of the arch bridge by increasing the yield strength of the longitudinal/cross beam.