Compressive behavior and strength prediction of ultra-high performance concrete confined by normal and high strength steel hoops. (7th November 2022)

• Record Type: Journal Article
• Authors: Shan, B.; Lv, Z.W.; Chen, J.Q.; Xu, C.; Xiao, Y.; Huang, B.
• Is Part Of: Construction & building materials. Volume 354(2022)
• Publication Date: 2022-11-07
• Subjects: Ultra-high performance concrete (UHPC) -- High-strength steel hoops -- Confinement -- Compressive behavior -- Load carrying capacity; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2022.129176
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: Steel hoop-confined UHPC stub columns were tested under axial compression load in order to reveal the compressive behavior differences between UHPC confined by normal- and high-strength steel hoops and quantify the load carrying capacity contribution from UHPC cover. Experimental results from the axial compression tests on the confined UHPC specimens were presented. A special strength model is proposed for UHPC columns confined by normal- and high-strength steel hoops to predict the axial load carrying capacity. Abstract: Ultra-high performance concrete (UHPC) confined by steel hoops exhibits obvious performance advantages under high temperature or corrosive environment compared with the external steel or fiber-reinforced polymer (FRP) jackets, due to protection to the confinement component by UHPC cover. However, some fundamental knowledge gaps need to be filled to promote the application of this type of composite column, including the compressive behavior of UHPC confined by high-strength steel hoops, influence of UHPC cover on the axial load carrying capacity as well as lack of acceptable strength model for predicting the load carrying capacity of steel hoop-confined UHPC column. Therefore, a series of axial compression tests on 78 UHPC stub columns confined by normal- and high-strength steel hoops were tested, with varying lateral confining levels and thicknesses of UHPC cove. The experimental results show that using high-strength steel hoops as lateral confining component can more effectively improve the post-peak behavior of confined UHPC column than its ascending behavior, compared with the UHPC confined by normal-strength hoops. The UHPC cover can directly carry a considerable share of peak axial load, thus cannot be ignored for evaluating the load carrying capacity of the confined UHPC column. A special strength model is proposed for UHPC columns confined by normal- and high-strength steel hoops to predict the axial load carrying capacity, and it is validated with experimental data derived from this investigation and opened literature.