Experimental Study on RC Beams Using Stay In Place GFRP Forms

Stay-In-place (SIP) formworks are considered as a novel construction technology. This paper presents an experimental study on conventional reinforced concrete (RC) beams strengthened by using SIP Glass Fiber Reinforced Polymer (GFRP) formwork. The experimental test program includes twelve specimens of RC beams without and with strengthening by SIP GFRP forms. Specimens were prepared and classified into four groups. The first group contains three RC solid beams without strengthening, and the second group contains three specimens of RC hollow beams without strengthening. The third group contains three specimens of RC hollow beams strengthened by using SIP GFRP forms. The fourth group contains three specimens of RC hollow beams strengthened by SIP GFRP forms as well as by additional three GFRP sheets at the tension side of the SIP form. The studied parameters include the ratio of main reinforcement, presence of hollow PVC tube, using SIP forms and the additional strengthening by using GFRP sheets. All specimens were loaded by four-point bending test until failure. For comparative study, the test results recorded the crack patterns, cracking and ultimate failure loads, mode of failure and load-deflection curves. The experimental results showed a significant improvement in the flexure behavior of RC beams using SIP GFRP forms compared with the corresponding reference beams without strengthening.