A theoretical strategy for moment redistribution in continuous FRP-strengthened concrete structures

The use of fiber-reinforced polymer (FRP) composites is now a widely-accepted solution for the strengthening of reinforced concrete structures. FRP strengthening schemes offer many well-documented benefits for the retrofit of many existing concrete buildings and bridges. However, the main drawback in using FRP for such purposes is the reduction in ductility that the strengthened structure displays after strengthening. This loss in ductility has led various design guidelines around the world to prohibit any redistribution of bending moments in continuous FRP-strengthened concrete structures. This means that continuous structures, which might have been designed originally under assumptions of moment redistribution, should be designed for FRP strengthening according to elastic distribution of bending moment. This could lead to onerous conditions for such strengthening schemes, particularly in hogging regions. This paper sets out a rationale for the possible appropriate use of redistribution principles for FRP-strengthened concrete.

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