Abstract
In recent years, carbon fiber reinforced polymer (CFRP) has been widely used in bridge repair, retrofitting, rehabilitation and strengthening to improve the bearing capacity. Although many studies have been conducted to explore the strengthening efficiencies of CFRP, the test specimens were small and the results were difficult to apply to full-scale bridges. Investigations into the strengthening effects of CFRP on real life structures rely on field load tests (without damaging the structures), making it difficult to understand actual improvements in load carrying capacity and strengthening effect. Moreover, there have been few experimental studies on the fatigue performances of CFRP-strengthened structures, especially on the large-scale structures with real wheel moving loads. In this study, the feasibility and efficiency of CFRP strengthening and repair was investigated on a large-scale, prestressed concrete hollow slab decommissioned from a real-life concrete bridge. The hollow slab was first put through a destructive test to test the ultimate load-bearing capacity. Then, CFRP strips were installed on the surface of the severely damaged slab to repair and strengthen it. Fatigue load test—including the moving load test and single point sinusoidal load—and load-bearing capacity tests were conducted on the CFRP-strengthened hollow slab after the destructive test to evaluate the strengthening performance. This study could help us to understand the actual load-bearing capacities of severe damaged concrete structures strengthened by CFRP, reduce waste, save resources and improve the utilization of our infrastructures.
Highlights
7 o prestressed carbon fiber reinforced polymer (CFRP) strips, the bending and bearing strength was improved by 18%, co strips, the bending and bearing strength was improved by 18%, compared to the original pared to the original hollow slab before the destructive test
CFRP-concrete bonding bonding surface surface of of the the CFRP-strengthened hollow slab, this study considered the main traffic loads on the top CFRP-strengthened hollow slab, this study considered the main traffic loads on the top of of the deck, deck, such such as as the the moving moving loads loads of of vehicles vehicles in in normal normal traffic, traffic, concentrated the concentrated loads loads when when vehicles stop stop on vehicles on bridges, bridges, and and impact impact loads loads when when vehicles vehicles accelerate accelerate or or decelerate
The comparison results indicated that the structural responses caused by the moving loads were generally greater than those caused by single point sinusoidal load, which means that the moving load had greater impact effects on the tested hollow slab
Summary
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. For hollow slab components with damage induced by overloading, carrying capacity can be improved through external reinforcement or strengthening approaches. In this way, the strengthened bridge components could remain in service. The drawbacks of concrete jacketing—such as possible bridge closure, increases in the weight of the bridge and the size of the structures, and high operation costs—limit the wide application of this technique in practice Another strengthening approach used for concrete involves the installation of bonded steel plates on the surface of the concrete to increase the load-bearing capacity. The investigation of strengthening effects of CFRP on real life structures relies on field load tests without damaged bridge structures It is difficult, to understand the real improvement of load carrying capacity and strengthening effects.
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