Nonlinear dynamic analysis of the self-anchored suspension bridge subjected to sudden breakage of a hanger

The self-anchored suspension bridge with post-stressed stiffening girders has been proved to be an appropriate bridge type where an external anchorage system cannot be easily provided. As one of the key components of the suspension bridge, hangers generally bear a high level of tensile stress and they are designed with sufficient structural redundancy. However, they also have a disadvantage of being sensitive to corrosion. The corroded hangers may suddenly break under hazardous circumstances, which will lead to dramatic vibration, internal force redistributions of the structure and even potential risks of progressive collapse. In this paper, structural performances of the self-anchored suspension bridge subjected to the sudden breakage of a hanger are studied through a nonlinear analysis in which the influence of corroded hangers is taken into consideration. To quantitatively describe the degraded behaviors of corroded hangers, a modified series-parallel system is developed. A prototype bridge is chosen as an example to demonstrate the assessment of structural dynamic responses. Finally, several useful recommendations closely related to the hanger-breakage event for the self-anchored suspension bridge are proposed.