Analysis of the Prestressing Loss Influence in Prefabricated Concrete Bridges Based on a Drop Weight Impact Method

The prestress loss of prefabricated continuous beam bridges directly affects their stress state and operating conditions. Excessive prestress loss can lead to increased mid span deflection of the main beam, cracking of the web and bottom plates, reduced bearing capacity, and even affect the safety of the structure. This study focuses on urban highway overpasses and measures the deflection of the bridge deck using the drop hammer impact method. The impact test of prefabricated segmental beam bridges was simulated using a finite element model, and the influence of prestress loss at different positions on the deflection basin of the bridge deck during operation was studied. The research results indicate that the factor causing the greatest damage to bridge stiffness is the loss of prestress in the bottom plate. When the prestress loss reaches 30%, the maximum response value increases by 33.6%. In contrast, the prestress loss of the roof has a smaller impact on deflection, with a maximum response value increase of 18.7%. This study provides important reference for evaluating prestress loss through impact testing methods in the future.