Stochastic modeling and design recommendations for bond of UHPC interfaced with steel, FRP reinforcing bars. (27th February 2023)

• Record Type: Journal Article
• Authors: Kim, Yail J.; Wang, Jun
• Is Part Of: Construction & building materials. Volume 367(2023)
• Publication Date: 2023-02-27
• Subjects: Bond -- Design -- Fiber-reinforced polymer (FRP) -- Interface -- Modeling -- Ultra-high-performance concrete (UHPC); Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2023.130297
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: The interfacial behavior of ultra-high performance concrete (UHPC) with steel and composite rebars is computationally examined. Assessments on existing and proposed approaches are demonstrated to claim the effectiveness of stochastic modeling. Design equations that can holistically cover UHPC reinforced with both steel and composite bars are suggested. Abstract: This paper presents the interfacial behavior of assorted reinforcing bars embedded in ultra-high performance concrete (UHPC), including steel, glass fiber reinforced polymer (GFRP), and basalt FRP (BFRP). The composition of UHPC varies by the presence of steel fibers and the amount of silica fume. In conformity with a previously conducted experimental program, stochastic simulations are carried out to predict the bond-slip response and damage progression of the interface categories. The computational approaches are implemented using microelement models in tandem with a genetic algorithm. The bond stress of the steel rebars incorporating deformed ribs linearly develops and abruptly drops due to the shear-off of the interfacial plane; however, the GFRP and BFRP rebars possessing smooth surface characteristics reveal a gradual declining pattern. Among the three reinforcement types, the post-peak residual bond stress of steel is the least favorable. Practical assessments show that existing equations taken from published specifications and literature are inapplicable to those nonconventional interface configurations; hence, design recommendations are suggested to encompass a strength range of UHPC from 123 MPa to 148 MPa with a silica fume to cement ratio of 20 % to 40 %.