DIRECT LOAD TRANSFER IN HYBRID FRP-CONCRETE SANDWICH STRUCTURE FOR BRIDGE DECKS

摘要

This paper presents results of direct load transfer experiments on hybrid FRP-concrete short span beam specimens for a novel bridge deck. The sandwich construction consists of three layers: a fiber-reinforced polymer composite (FRP) sheet with T-upstands for the bottom skin, lightweight concrete (LC) for the core and a thin layer of ultra high performance reinforced concrete as a top skin. Different LC types were used: a low and a high density sand lightweight aggregate concrete (SLWAC) and an all-lightweight aggregate concrete (ALWAC). Specimens with adhesively bonded FRP-LC interfaces showed significantly higher ultimate loads than corresponding unbonded specimens with composite action due to pure mechanical interlocking. The degree of composite action of the unbonded interfaces thereby depended on the LC compressive strength. A correlation of the ultimate loads and the LC splitting tensile strengths was found. Combining the LC splitting tensile strength and the LC characteristic length led to a good correlation with the cracking loads.