Abstract

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Title:: Calculation Model of Deflection and Crack Width of Concrete Beam Reinforced with FRP Bars

Author(s):: LIU Xi; WANG Zheng; WU Tao; School of Civil Engineering, Chang’an University

Keywords:: concrete beam reinforced with FRP bar; flexural member; deflection; crack width; nonuniformity coefficient of strain

Abstract:: The 218 groups of flexural test results at home and abroad of concrete beams reinforced with fiber reinforced polymer (FRP) were collected, and the development laws of beam deflection and crack width under serviceability limit state and ultimate limit state were studied emphatically. On the basis of test data, the relationship between the nonuniformity coefficient of FRP strain and influence coefficient of strength reinforcement was corrected, and the deflection calculation model of flexural member was established. The influences of coefficient of internal force arm and force characteristic coefficient of component of the FRP reinforced concrete beam bending section on the calculation accuracy of crack width were deeply analyzed. The reasonable values of η?and α_cr?were determined, and the calculation model was optimized. The calculated values were compared with that of the model proposed by technical code GB 50608—2010 for infrastructure application of FRP composites. The results show that the suggested model by selecting η=0.88, α_cr=1.5 based on the relationship between ψ?and influence coefficient of strength reinforcement can predict the deflection and the crack width of concrete beams reinforced with FRP bars better than GB 50608—2010, and the calculation results of modified model are in good agreement with experimental results, the accuracy and rationality of the proposed model is verified.