Interfacial shear performance of UHPC-strengthened RC structures using post-installed rebar connections: Experiments and analyses. (15th February 2023)

• Record Type: Journal Article
• Authors: Sun, Wenbiao; Fan, Wei; Yang, Jie; Zhang, Yang; Zhong, Zhengwu
• Is Part Of: Engineering structures. Volume 277(2023)
• Publication Date: 2023-02-15
• Subjects: Ultra-high performance concrete (UHPC) -- Reinforced concrete (RC) -- Post-installed rebars -- Interface shear -- Push-out test -- Minimum implant depth -- Bearing capacity; Structural engineering -- Periodicals; Structural analysis (Engineering) -- Periodicals; Construction, Technique de la -- Périodiques; Génie parasismique -- Périodiques; Pression du vent -- Périodiques; Earthquake engineering; Structural engineering; Wind-pressure; Periodicals; 624.105
• DOI: 10.1016/j.engstruct.2022.115411
• Languages: English
• ISSNs: 0141-0296

Abstract

Highlights: Explored the influence of different UHPC-based rehabilitation forms with the post-installed rebar connection. Clarified the mechanism of different failure modes with the different embedded depths of post-installed rebar. Established and verified a method to determine the minimum embedded depth required for the post-installed rebar. Characterized the force–displacement curves of the post-installed rebar connection under shear loads. Proposed a calculation formula to estimate shear bearing capacity for post-installed rebar connection. Abstract: The reliable bonding effect between the ultra-high performance concrete (UHPC) layer and the existing reinforced concrete (RC) components is always expected when UHPC is used to rehabilitate deteriorated RC structures. The post-installed rebar connection has been demonstrated to possess robust mechanical performance. However, no research to date clarifies how to design the post-installed rebar connection in engineering practice. To this end, this study conducted 34 push-out tests to investigate the interfacial shear performance of UHPC-strengthened RC structures using post-installed rebar connections. The primary variables in the tests included strengthening form, embedded depth of rebar, rebar diameter, rebar spacing, and substrate type. Based on the test results, three different failure modes were identified. The analytical results indicate that the embedded depth of the rebar has a significant influence on the performance of the post-installed connection. A formula was proposed to determine the minimum embedded depth, and its accuracy was validated by the physical experiments. The load-bearing mechanisms were revealed based on the experimentally measured force–displacement curves. The shear capacity of the connection mainly comprises the adhesive effect, rebar shearing, and friction. The connection capacity can be approximated by the rebar shear capacity due to its robust shear resistance. Also, a formula was proposed to estimate the shear capacity of the rebar. The experimental and theoretical results facilitate the design and application of post-installed rebar connections in UHPC-strengthened RC structures.