Design and Construction of CFRP Rod Panel Retrofit for Impacted RC Bridge Girders

Abheetha Peiris,Issam Harik

doi:10.3390/jcs2030040

Abstract

CFRP Rod Panels (CRPs) have been recently developed to externally strengthening concrete structures in flexure, especially over multi-lane highways. Both exterior beams of a reinforced concrete (RC) bridge traversing southbound Interstate 71 (I-71) in Kentucky were damaged by an over-height truck impact. Rebars within the bottom mat of each exterior beam were severely bent due to the impact. CRP 195, with CFRP rods 3.96-mm (0.156 in) in diameter, and having a capacity of 870 kN (195.6 kips) per 300 mm (12 in) width of panel, were selected for flexural strengthening. CRPs were chosen due to their modular construction capability permitting a smaller work crew to carry out the retrofit construction while requiring closure of only a single lane of traffic on I-71. As current codes do not address CRPs, the retrofit design was based on American Association of State Highway and Transportation Officials (AASHTO) guidelines for externally bonded FRP. A load rating of the impacted girders was carried out for the as-built, damaged, and retrofitted stages. This paper details the retrofit construction of the bridge girders, highlighting the advantages of the CRPs.

Highlights

Bridge superstructures in the United States (US) and throughout the world are routinely damaged by over-height truck impacts
Carbon Fiber Reinforced Polymer (CFRP) Rod Panels (CRPs) were required on the bottom face and on the sides of the girders to account for the loss of the rebars
The retrofit design was primarily based on Association of State Highway and Transportation Officials (AASHTO) guidelines for using externally bonded CFRP (EB-CFRP) to strengthen concrete bridge elements

Summary

Introduction

Bridge superstructures in the United States (US) and throughout the world are routinely damaged by over-height truck impacts. Damage caused by over-height truck impacts to RC and PC bridge beams include cracking of beams, damage to reinforcement and/or prestressing strands, yielding of steel, spalling of concrete, and failure of joints and connections, among other types. While numerous laboratory and field applications of strengthening RC beams are available, there are no guidelines or research publications known to the authors which address the impact damage repair of RC bridge girders. Following an over-height truck impact to a bridge, most state departments of transportation (DOTs) in the US evaluate damage and decide whether a load posting is necessary Unless it is extremely unsafe and requires immediate attention, impact damages may only be fixed several months or years after the actual impact, when funds are available. The paper details the damage caused by an over-height truck impact to an overpass over Interstate 71 (I-71) in Kentucky and the design and retrofit of the impacted RC girders using CRPs

CFRP Rod Panels

Bridge and Damage Details

Retrofit Construction

Conclusions

Findings

Design