.140 M, Bearing Steel Box Tied Arch Bridge Key Parts Of Local Stress Analysis

The 140m span through tied-arch bridge with steel box is a double-track railway bridge which is across bejing-zhuhai highway in wuhai-guangzhou passenger railway line. Rigid joints are applied in the bridge. The stress state of the joints is complicated . In the finite element analysis of the whole bridge the details of the joints are difficult to simulate. Therefore local analysis of the key joints is necessary. The main work has been done as follows:1. Based on the analysis of the whole bridge three representative joints were chosed. The first is arch foot which are the joint of arch and tie-beam, the joint of tie-beam and end cross-beam, the joint of tie-beam and assisted cross-beam. The second is the joint of the arch and the first suspender. The last is the joint of first suspender, tie-beam and cross-beam.2. The methods of local analysis has been studied. According to the Saint-Venant Principle the principle of the interception was proposed and the method of application of force boundary of the joints was proposed.3. Local analysis of the arch foot has been done. Results of the finite element analysis were coincident with the experimental results. General stress level was not high, but at the connection of end cross-beam and tie-beam stress concentration happened and the highest equivalent stress reached to 297MPa. Stress concentration also happened at the right angle of arch and tie-beam connection, round chamfer was suggested to applicate.4. Local analysis of the joint of the arch and first suspender has been done. Total stress level was not high. But at the top of web and flange connection the stress was more high, and the highest equivalent stress reached to 207MPa. Comparing the FEM results of variable and I-type cross-section suspender, uniform cross-section were better in the mechanical behavior.5. Local analysis of the joint of the first suspender, tie-beam and cross-beam has been done. General stress level was low. The highest equivalent stress was less than 87MPa.The research results of this paper can provide the basis for the local structure design of 140m span though tied-arch bridge with steel box and provide references for the bridge of similar type.