Date of Award


Publication Type

Master Thesis

Degree Name



Civil and Environmental Engineering

First Advisor

El Ragaby, Amr

Second Advisor

Cheng, Shaohong


GFRP; Prestressed Hollow Core Slabs; Shear Strengthening




Precast prestressed hollow core (PHC) slabs are widely used as floor deck systems. However, as extrusion is the most widely adopted manufacturing technique of PHC slabs, it is difficult to arrange shear reinforcement during casting using an extrusion machine. Therefore, the shear capacity of a PHC slab relies on the shear strength of plain concrete, which makes them prone to shear failure near the support. Traditional solutions to increase the shear capacity of PHC slabs would add more weight and cost. Externally bonded fibre reinforced polymers (FRP) sheets have been successfully used over the past 20 years as an efficient technique for strengthening both the flexural and shear capacities of reinforced concrete members. During the first two phases of this research project, externally bonded carbon fibre reinforced polymers (CFRP) sheets along the internal perimeter of the PHC slab voids have proven to considerably increase the shear capacity of PHC slabs by up to 40%. The objective of the current research, which is Phase III, is to investigate and compare the effectiveness of glass fibres reinforced polymers (GFRP) sheets to CFRP sheets used in Phase I and Phase II to enhance the shear capacity of PHC slabs. A total of 11 full size PHC slabs, 1219 mm wide, 4500 mm long and 305 mm thick, were tested in Phase III. The effects of fibre type, the prestressing level, the width of the GFRP sheets, and the installation procedures for the shear capacity of PHC slabs were investigated. The ultimate strength, deflection, strands’ slippage, concrete strain and FRP strain were recorded, analyzed and compared to the results obtained in the previous study. The testing results show significant enhancement in the shear capacity and the behaviour of the PHC slabs strengthened by externally bonded GFRP sheets along the internal perimeter of the PHC slab voids comparable to the effect of the CFRP sheets.