Refined Analysis of Anchorages of South Navigation Channel Bridge of Zhangjiagang-Jingjiang-Rugao Changjiang River Bridge
The south navigation channel bridge of Zhangjiagang-Jingjiang-Rugao Changjiang River Bridge is a two-tower,steel box girder suspension bridge with a main span of 2 300 m,featuring two unequal suspended spans.The main cables of 70 000-t tension force are anchored to the giant south and north gravity anchorages via the posttensioned prestressing systems.The mechanical behaviors of the anchorage bodies are complex.To direct the anchorage structure design of the south navigation channel bridge,the south anchorage exhibiting greater horizontal component was selected for refined analysis in accordance with the design requirements,and the design suggestions were given.A finite element model of a half of the south anchorage and a slice model along the central cable strands were established to analyze the distribution characteristics of the stresses in the entire anchorage as well as in the local zones and bottom of the anchorage,considering two loading scenarios(prestress tensioning stage and main cable tensioning stage).A force flow analysis method that is developed based on the principal stress trajectory and boundary stress distribution was proposed,by which the trajectories of principal tensile and compressive forces inside the anchorage were analyzed.It is shown that the overall stress level of the anchorage was low,stress concentrations were observed in the anchor zones of the rear anchor surface as well as the top and bottom sides of the rear anchor surface,and significant shear and tensile stress combinations existed in the bottom of the front of the rear anchor chamber.Moreover,substantial tensile force flow was found in the top and bottom sides of the rear anchor surface as well as the end zones of the anchorage.It is recommended to extend the reinforcement in the front and rear anchor surfaces and add more vertical reinforcement in the bottom of the front of the rear anchor chamber.
suspension bridgegravity anchorageanchorageprincipal stress trajectoryforce flowreinforcement designfinite element method
万方数据
维普
