RESPONSE OF R. C. BOX GIRDERS STRENGTHENED USING CFRP SHEETS

Reinforced concrete box girders RCB are important elements in concrete bridge structures, which resist loads acting on the carriage way. The main objective of this study is to investigate the effect of external strengthening technique using carbon fibre reinforced polymer CFRP sheets on the behaviour of RCB girders. The experimental program of this study includes ten RCB girders. Two girders are reference specimens, and the other eight were divided into three groups. Groups G1 and G2 contain three girders each, while group G3 contains two girders. In groups G1, G2, and G3, strengthening sheets were located at the bottom surface, side surface and both bottom, and side surfaces, respectively. The length of such sheet was quarter, half and full span length. The tested girders were loaded by incremental increasing static loads till failure. Crack, ultimate loads, along with under load, and central girder deflections at each load level were recorded. Test results were plotted, analysed, compared with average results from the references, and they were studied, and discussed. Results show an increase in ultimate and crack loads, as well as good improvement in overall flexural behaviour