Safety assessment of a concrete viaduct damaged by vehicle impact and an evaluation of the repair

Abstract

Damage to lower parts of viaducts caused by impact from under-passing high vehicles is relatively frequent. One such incident, in which a viaduct was damaged by the impact from a truck with an improperly assembled hydraulic crane, is considered in this work. The analysis is based on a detailed object damage evaluation, 3D laser scanning, and numerical simulations. The aim of the study is to accurately model the vehicle impact into the viaduct's span. The objective is to diagnose internal damage and to assess the proposed repair concept. No other method will allow discovery of the internal damage, including whether the pre-stressing tendons have been damaged or not. The computational model considers non-linear system dynamics including advanced material definition and the technology of tendon pre-stressing. All complex stages of structural assembly are included in the simulations and the extent of bridge damage is diagnosed. This approach makes it possible to reliably restore the collision event and to assess the safety of internal structural parts. The results from the numerical simulation correspond to the damage measured on the full-scale object. The conducted research indicates that tendons were not damaged as a result of vehicle impact. The structure may be strengthened by means of assembling prestressed concrete girders at both ends. This restoring concept is confirmed analytically. The strengthened structure is intended to show an even greater safety reserve. The proposed strengthening substantially improved structural stiffness, significantly reducing concrete damage and tendon stress in the case of a similar impact in the future. The proposed methodology can also help with research and in practice to assess the safety of other similarly struck and damaged bridges.