Title:
Strength Characteristics Of Precast Reinforced Concrete Inverted U Bridge Beams
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Publication:
CIA
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Date:
2/13/2011
Abstract:
Main Roads Western Australia have a number of bridges constructed from precast reinforced concrete inverted U beams (approx 6400 mm long, 940 mm wide and 410 mm deep). These bridges were designed and constructed in the 1950s with plain bar reinforcement for single axle trucks and concern has been expressed about their shear capacity and moment capacity at the location of curtailment of the main flexural reinforcement. Recently three bridges were removed from service and replaced with new construction. This provided the opportunity to test the ultimate capacity of the removed beams. A series of laboratory tests was conducted as the initial phase of research into the strength characteristics of these beams. The testing utilised 7 standard internal beams, 7 nonstandard internal beams with external strengthening by 100 mm by 10 mm steel plate and six standard internal beams which had 80 mm by 1.2 mm carbon fibre straps applied to the bottom of both webs as part of the testing program. The strengthening methods increased the stiffness of the beams and resulted in strength increases of between 20% to 70% when compared with the standard beams.