Abstract: In order to realize the rapid quantitative assessment of the strengthening effect of existing highway bridges without interrupting the normal traffic, this paper takes the prestressed CFRP plate strengthened hollow slab footbridge as the test object, and derives the formula of the long-gauge strain influence line for simply supported beam bridge under moving vehicle load based on the long-gauge fiber grating strain sensing technology. On this basis, the performance characteristics of the long-gauge strain influence line before and after the bridge strengthening with prestressed CFRP plates were studied, and the evaluation index of the bridge strengthening effect based on the long-range strain time-area envelope under the moving vehicle load was proposed. Finally, a footprint test study of prestressed CFRP plate reinforced hollow slab girders was carried out, and the reinforcement effect was rapidly evaluated and monitored. The test results showed that the bridge reinforcement effect based on the long-gauge strain influence line of the bridge under moving vehicle load can effectively evaluate the bridge reinforcement effect of prestressed CFRP plate, and the long-gauge strain time range area decreases with the increase of the prestressing level of CFRP, and the bridge reinforcement effect in this reinforcement test is 7.07% and 6.90% respectively through the evaluation and analysis.

Key words: prestressed CFRP plate, bridge reinforcement, long-gauge strain sensor, reinforcement effect, rapid assessment