Inspection, Analysis and Loading Test of a Slab Bridge Strengthened with FRP Laminates

Abstract

The advantages of FRP as a strengthening material have been widely recognized in recent years. Typical applications of FRP have extended from repairing of cracked columns, beams, bridge decks to enhancing the load capacity of critical structural components. As a demonstration of application of FRP laminates in concrete bridge decks with no transverse reinforcement, the Rolla Bridge in Missouri is selected for this study, which is a two-span simply supported reinforced concrete slab with no transverse steel reinforcement. The original construction combined with the presence of very rigid parapets caused the formation of a wide longitudinal crack which resulted in the slab to behave as two separate elements. The strengthening scheme was designed to avoid further cracking and such that the transverse flexural capacity be higher than the cracking moment. An initial load test, to evaluate the structural behavior, was performed prior the strengthening. The retrofitting of the structure was employed after the major cracks were injected to allow continuity in the cross section. Once the repair work was completed, another load test, identical in procedure to the previous one, was performed to evaluate the efficiency of the strengthening. No additional cracking was observed in the concrete decks as a result of the strengthening program.