A novel hyperboloid cone model for predicting tensile performance of studs in concrete of various properties

Abstract

Concrete breakout (CB) failure is the most common failure mode for studs in tension. Based on the Griffith's strength theory, Mohr's circle method, and mechanics of materials, the breakout cone failure model and failure mechanism of the CB mode are analyzed; the shape of the breakout cone is hyperboloid cone, and the failure of CB mode is due to the concrete tensile failure. The classic concrete capacity design (CCD) method only applies to normal concrete (NC) substrate. To predict ultimate tensile strength (Nb) of the CB mode for a wider range of concrete properties, including high-strength concrete (HSC), ultra-high performance concrete (UHPC), engineered cementitious composite (ECC), etc., a new "Hyperboloid Cone Model" is proposed, which is based on the original form of CCD method and the Griffith's strength theory. The comparison between the experimental and predicted Nb for the studs in various substrates (NC, HSC, UHPC, and ECC) from past studies shows that the prediction of the proposed model on Nb is more accurate with significantly smaller variances compared to CCD method; the average ratio of the experimental to calculated value of the proposed model and the CCD model is 0.974 and 1.138, respectively, while the coefficient of variance of them is 11.27% and 40.44%, respectively.