Shear Strengthening of Hollow Core Slab Webs using FRP Composite Sheets

摘要

Precast, prestressed hollow core (PHC) slabs are among the most common concrete deck system in the world. However, due to the manufacturing constraints and the difficulty in providing internal shear reinforcement, the shear capacity of PHC slabs sometimes dictates the design and reduces the efficiency and economics of PHC slabs. The objective of this research project is to develop an innovative application of externally bonded Fiber-Reinforced Polymers (FRP) sheets by installing the sheets along the internal perimeter of the slab voids to strengthen the web-shear capacity of PHC slabs. To explore the feasibility and to optimize the new technique, experimental testing was carried out on eight full-scale single web, I shape, specimens (each of 4575 mm '180 in' long, 300 mm '12 in' thick and a 284 mm '11.2 in' wide) that were cut longitudinally out of the PHC slab. Carbon FRP sheets were bonded along the full perimeter on each side of the web specimens. The test specimens were loaded monotonically until failure under single concentrated load at a shear span/depth ratio of 2.5. The investigated parameters were the width of the FRP strengthened zone (300 '12 in.', 450 '18 in.', and 600 mm '24 in.') and the number of strengthening layers (2 and 4 layers). The test results showed the efficiency of the proposed technique to enhance the shear strength of PHC slabs.