Fatigue experiment of sectional integrated model of a suspension bridge

Abstract

Previous fatigue tests have placed emphasis on single components such as the anchorage zone, orthotropic steel deck or hanger of suspension bridges, and the test results were thus influenced by many boundary conditions. However, the stresses of such components are complex and boundary conditions have a marked impact on fatigue test results. To evaluate the safety and durability of key structural details and verify the design rationality, fatigue tests on a 1:4 scale integrated model were carried out; the model included the main cable, anchorage zone, hangers and box girders. The experiment results showed that stress redistribution in the integrated model after fatigue loading cycles was not obvious, the principal stresses of static load tests during the fatigue experiment were a little different and the relationship between displacement and static load was approximately linear. In each static load test, displacements and stresses in the process of loading and unloading showed good symmetry and recoverability, indicating that the integrated model was in the elastic stage. Fatigue cracks were not found in key structural details under fatigue loading, so structural fatigue performance may meet the design requirements. The integrated model fatigue test can more truly reflect the actual fatigue performance of a cable–anchorage–hanger–girder structure and can provide some guidance on actual projects.