Fatigue Behavior of a Composite Bridge Deck with Prestressed Basalt Fiber-Reinforced Polymer Shell and Concrete

摘要

Concrete bridge decks often suffer from traffic fatigue loads and severe corrosive environments. To overcome these problems, a novel high-performance composite bridge deck with an upper concrete and lower basalt fiber-reinforced polymer (BFRP) shell was developed. The shell-concrete interfacial behavior and static behavior of this deck have been studied previously. In this study, the fatigue behavior of this composite bridge deck was investigated considering five different fatigue load levels ranging from 0.439 to 0.649. The fatigue load level was defined as the ratio of maximum fatigue load F-max to static load capacity F-u. The failure modes, deflection and strain development, fatigue damage evolution, and prediction model of fatigue life were analyzed. The results demonstrated that, with the fatigue load levels varying from 0.511 to 0.649, the fatigue failure of the bridge deck was characterized by flexural punching failure of concrete, with a residual load capacity of 67% of the ultimate static capacity. Under the fatigue load level of 0.439, the specimen survived 10 million cycles with a 92.5% residual capacity. The strain profile of the section was almost linear under fatigue load, with only a slight descendance of the neutral axis. After the fatigue failure, the BFRP shell and prestress strips were almost still intact. The interface between the concrete and the shell also remained effective. The regression fitting of fatigue S-N curves indicated that, under 2 million cycles, the maximum allowable fatigue load of the deck was more than twice the design demand values.