A Forensic Analysis of Structural Failure in a Suspension Bridge in Upala, Costa Rica

The failure of a structure can occur due to various aspects, among these that the design decisions are not consistent with the construction and reality of the structure. This study carried out a forensic analysis of the structural failure that occurred in a 57 m long vehicular suspension bridge. The main objective of this study was to identify the cause of the structural failure that affected the trusses of the suspension bridge. To achieve this objective, a meticulous forensic analysis of the project was carried out. This analysis involved a detailed review of the documentation related to the structure. Additional information necessary for the study of the bridge was obtained, which included a detailed geometric survey of the bridge, testimonies and information about materials. A detailed inspection of the damages was carried out. Subsequently, an analytical study was conducted, using third-order computational analysis to include the effect of large deformations. The results of the study indicate that the designer did not consider the stiffness and strength of the truss in the design of the bridge, which resulted in the bridge’s buckling failure due to a vehicle with an approximate weight of 24 tons. In conclusion, it was determined that the failure was because the decisions in the design process were not consistent with how the bridge was built.