Title:
Dynamic Evaluation and Retrofitting of Prestressed Concrete Girder Bridges with Vibration Problems
Author(s):
Nur Yazdani, Andy Foden
Publication:
Web Session
Volume:
Issue:
Appears on pages(s):
Keywords:
DOI:
Date:
10/29/2023
Abstract:
Though often ignored, the unusual vibration of highway bridges causes human discomfort and affects the serviceability and durability of the deck. A recently constructed prestressed concrete I-girder bridge in the Dallas-Fort Worth metroplex experienced excessive vibration, leading to extensive transverse deck cracks and potholes. Non-Destructive Evaluation (NDE) and diagnostic load test revealed severe delamination on the deck and partial composite action at the deck-girder interface. An ambient vibration test on the bridge showed a considerably low natural frequency due to partial-composite action-induced stiffness reduction of the bridge. A Finite Element Model was developed and calibrated using the NDE and diagnostic load test results. The model was subsequently used to evaluate vibration mitigation retrofitting techniques, such as concrete shear keys restrainer between girders, dense concrete deck overlay, undercut anchors at the deck-girder interface and re-casting the deck areas with extensive delamination. Shear keys resulted in the most significant improvement in the bridge's natural frequency. In addition, it is the cheapest option and does not require traffic closure since the bridge bents are located outside the traffic.