Title: Rehabilitation for shear strength of prestressed concrete girders and continuity reinforcement of bridge deck slabs along with full load test verification
Date Published: March - April 2026
Volume: 71
Issue: 2
Page Numbers: 39 - 57
Authors: Durgesh Rai, Shambhavi Dube, and Vaibhav Singhal
https://doi.org/10.15554/pcij71.2-02

Abstract

This paper presents a study, including the investigation, analysis, rehabilitation, and verification through full-load testing, of two adjacent overpass bridge structures that experienced significant structural damage shortly after entering service. The bridges comprise multiple units, each having three simple-span precast, pretensioned concrete girders made continuous through cast-in-place concrete diaphragms and deck. Structural damage included flexure cracks in the deck slab and web shear cracks in girders near supports. Investigations identified several contributing factors, including discrepancies between assumed and actual construction sequences, shear strength deficiencies in girders due to excessive strand debonding, inadequate shear reinforcement, and insufficient negative moment continuity reinforcement in the deck slab. Rehabilitation involved externally bonded and bolted steel plates on debonded girder webs near supports and additional negative moment continuity reinforcement through a new concrete overlay on the existing deck. A full-load test confirmed the effectiveness of these measures under design vehicle loads. The rehabilitated bridges successfully carried the design loads, with strengthening elements effectively contributing to the load-resisting mechanism. A numerical model developed using bridge modeling software validated observed response quantities. This study illustrates a methodical and practical approach to addressing structural deficiencies in prestressed concrete girder bridges caused by excessive strand debonding and inadequate continuity reinforcement, providing insights for en-hancing long-term safety and performance.