Theoretical verification of an alternate load path system applied to an existing truss bridge to prevent collapse.

摘要

Collapse of non-load path redundant structures is a growing concern in the United States. With many of the structures in our nation's infrastructure reaching their design age, many bridges are vulnerable to this type of failure. Truss bridges in particular are a major concern since many older truss bridges are classified as nonload path redundant structures, in which a failure of one component will result in a catastrophic structural collapse. A potential solution to this problem is designing a system to redirect load around a damaged joint, creating an alternate path for the load to travel through. The implementation of an alternate load path system to deteriorated truss connections can be a rapid and economical solution to extend the design life of truss bridges by protecting against collapse. The system will consist of high strength struts and cuff joints attached to the existing truss members to safely transfer the load around a failed truss connection. To design an alternate load path system, a theoretical two-dimensional analysis to verify that design of such a system is possible and plausible is required. This analysis must verify that the alternate load path system is capable of transferring the loads, will not impose excess additional load onto the existing truss members, and can perform properly under a real loading scenario. Upon completion of two-dimensional testing to determine the most efficient alternate load path system, the New Hope-Lambertville Truss Bridge was chosen as a case study and modeled for analysis. This structure was then tested with the ALPS applied, and it was concluded that application of the ALPS will safely transfer the loads around a damaged node without causing any major increases of force or moment to the existing truss members.