Date of Award
Master of Science in Civil Engineering (MSCE)
Tamer El Maaddawy
Ahmed E1 Refai
Shamim A. Sheikh
This research examines the viability of using different composite-based systems to upgrade the shear resistance of shear-deficient reinforced concrete T-girders. The research comprised experimental testing and analytical investigation. Test parameters included the retrofitting system; externally-bonded carbon fiber-reinforced polymer (EB-CFRP) laminates with or without a mechanical end anchorage (MA) and embedded through depth glass fiber-reinforced (ETD-GFRP) rebars; amount of internal stirrups; no stirrups, limited amount of stirrups with spacing s1 = 0.6d, higher amount of stirrups with spacing s2 = 0.375d; and initial shear damage prior to retrofitting; no damage, pre-cracking, and pre-failure.
The shear strength gain for the non-damaged specimens decreased as the amount of stirrups increased. The EB-CFRP system without MA increased the shear resistance by 17, 19, and 13%, for the specimens without stirrups, with stirrups spacing S1 and S2, respectively. The inclusion of the MA in the EB-CFRP system increased the former shear strength gains to 64, 36, and 32%, respectively. The shear strength gains provided by the ETD-GFRP system were comparable to those provided by the EB-CFRP with MA.
The presence of shear damage prior to retrofitting significantly reduced the strengthening effectiveness. For the pre-cracked specimens with the lower amount of stirrups, only 11, 27, 11% shear strength gains were recorded after retrofitting with the EB-CFRP solely, EB-CFRP with MA, and ETD-GFRP systems, respectively. The EB-CFRP system without MA was not successful in restoring the shear resistance of the pre-failed specimens. The EB-CFRP with MA and ETD-GFRP systems fully restored the shear resistance of the pre-failed specimens. The shear resistance of the pre-failed specimens retrofitted by the EB-CFRP with MA was 1.1 to 1.4 times the original shear resistance compared to 1 to 1.1 times for the pre-failed specimens retrofitted with the ETD-GFRP system.
In the analytical investigation, the accuracy of five different international guidelines/standards and two recent analytical models published in the literature to predict the contribution of the EB-CFRP system to the shear resistance have been assessed. The validity of a recent analytical approach published in the literature to predict the contribution of the ETD-GFRP system to the shear capacity has been demonstrated.
Ata Maali, Alaa Ahmad, "Retrofitting of Shear-Deficient Reinforced Concrete T-Girders with Composite-Based Systems" (2014). Theses. 519.