Innovative development of GFRP girders filled wiht concrete

Three types of FRP, namely CFRP, AFRP, and GFRP, have been used in the construction field. Among them, GFRP is usually used as the structural material to develop FRP girders, because it is the most economical. However, its modulus of elasticity is the lowest, which may result in large deflections exceeding the serviceability limit state. To meet the deflection requirement, unnecessarily large sections have to be used, too much safe at the ultimate state. Furthermore, there have not been facilities yet to produce such a large size FRP girders to be used as bridge girders in Korea. An innovative composite concept has been developed to form large size GFRP girders by assembling small modular b eams, filled with concrete at the top and bottom parts. In addition, pre-stressing may be introduced using FRP tendons to reduce the deflection, if necessary. Experimental tests have been conducted on small modular GFRP beams filled with concrete. The tests have shown that it is possible to reduce the deflection and to enhance the strength effectively by filling GFRP beams with concrete. Based on the test results of unit beams, numerical analyses of bridge girders with assembled large sections were carried out. Consequently, the application of these innovative large GFRP girders seems highly feasible in bridge constructions, if filled with concrete, and/or if pre-stressed with CFRP tendons, whenever necessary.