Shear Strength of GFRP-Reinforced Concrete Squat Walls: A Strut-and-Tie Model
Islam Shabana, Ahmed Sabry Farghaly, and Brahim Benmokrane
Appears on pages(s):
design codes; experimental and analytical modeling; glass fiber-reinforced polymer (GFRP) reinforcing bars; load paths; reinforced concrete (RC); seismic; shear strength; squat walls; strut-and-tie
Increasing interest in the use of fiber-reinforced polymer (FRP)
reinforcement for reinforced concrete (RC) structures has made it clear that insufficient information about the seismic performance of such structures is currently available for practicing engineers. This paper summarizes the results of seven full-scale pseudo-static cyclic tests of squat concrete walls reinforced with glass FRP (GFRP) bars and spirals. Test variables were the wall aspect ratio, the axial load level, and the web reinforcement amount. The test results were analyzed and used to develop a strut-and-tie model (STM) that accurately estimates the peak shear strength and reflects the effects of various influential parameters. The model was achieved by idealizing the shear-transfer mechanism of the web reinforcement using a statically indeterminate truss, and that of the concrete using a direct strut-and-tie system representing the tiedarch action developed through the web. Streamlined expressions were formulated to calculate the shear-transfer capacity of the two mechanisms, and due to lack of a sufficient experimental database, a series of 90 finite element models were conducted to assist in formulating the truss expression. The validity of the developed STM and expressions was examined against the results of the tested walls, showing great accuracy and uniformity. Comparisons were also made with predictions from STMs in ACI 318-19, CSA S806-12, and Eurocode 2 to indicate the accuracy of the developed model.