Abstract
The redundancy analysis is used to check the performance of bridges after sudden failure of their tension members. The current redundancy analysis is mainly based on a linear static analysis where the dynamic effect due to the sudden failure of the tension members is approximately considered by the socalled impact coefficient (i.e. dynamic to static ratio). This implies that the current redundancy check is done by the strength check method within the frame work of the allowable stress design. Therefore, the only way for the current redundancy analysis to improve the redundancy of bridges is to increase the strength of their members. However, the increase in member strengths will result in the increase in dynamic effects and may cause metal fracture in connections. In addition, it will be costly to improve the redundancy of structures by just increasing the strengths of members. Herein, an energy-based redundancy analysis is presented to take into account the energy dissipation capacity of the truss bridges due to the plastification of remaining members after the failure of some members. This energy dissipation capacity is utilized to reduce the dynamic effect. The proposed energy-based redundancy analysis is practical because the energy dissipation capacity is statically evaluated by the pushover analysis. By the use of the proposed method, the redundancy of structures may be improved not only by the increase of member strengths but also by the increase of the energy dissipation capacity.
