Novel fiber reinforced polymers (FRP)-ultrahigh performance concrete (UHPC) hybrid beams with improved shear performance

• Published in: Construction & building materials Vol. 286; p. 122720
• Main Authors: Zhang, Pu, Lv, Xinlei, Liu, Ye, Zou, Xingxing, Li, Yaozong, Wang, Jingquan, Ahmed Sheikh, Shamim
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 07.06.2021
• Subjects: Composite action; FRP-UHPC hybrid beam; Shear capacity; Shear connection; Slip effect; Shear capacity; Composite action; Slip effect; FRP-UHPC hybrid beam; Shear connection
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2021.122720

•Externally bonding CFRP to GFRP profiles webs substantially increased the shear capacity and stiffness of FRP-UHPC hybrid beams.•A novel built-up II-shaped GFRP profile showed much higher shear capacity than single web I-shaped CFRP profiles.•The influence of UHPC slab height and shear span length were investigated by comparative tests and parametric study. Fiber reinforced polymer (FRP) and ultrahigh performance concrete (UHPC) are two durable and high strength construction materials. FRP-UHPC hybrid beam is a durable and efficient bridge superstructure, however, its capacity is limited by the low shear strength of FRP profiles. This paper investigated two ways to improve the shear performance of FRP-UHPC hybrid beams: externally bonded (EB) carbon FRP (CFRP) sheets to the webs of glass FRP (GFRP) profiles, and increasing the number of webs of FRP profiles. Nine FRP-UHPC hybrid beams were tested under bending loads, which indicates: (i) EB CFRP sheets to GFRP webs substantially increased the shear capacity and the rigidity of FRP-concrete hybrid beams. (ii) the built-up II-shaped FRP profiles had almost doubled the shear capacity of FRP-concrete hybrid beams using I-shaped profiles. (iii) With UHPC height increased from 30 mm to 80 mm, the failure mode changed from the shear fracture of UHPC slab to the interfacial disconnection. (iv) With the decrease of shear span length from 700 mm to 120 mm, the shear capacity was largely improved. In summary, EB CFRP sheets and using double web GFRP profiles are two effective ways to improve the shear performance of FRP-UHPC hybrid beams.