Strength predictions of circular hollow section T-joints of steel grade 1100 MPa

Abstract

This paper presents experimental and numerical investigations of cold-formed high strength steel (CFHSS) circular hollow section (CHS) T-joints. The CFHSS CHS members have nominal 0.2% proof stress of 1100 MPa. The geometric parameters of the T-joints were designed by varying the ratios of β, 2γ and τ. A total of twelve T-joint tests were conducted by applying axial compressive load through the braces without preloading in chords. Non-linear finite element (FE) model was then developed for the CFHSS CHS T-joints. After successful validation, parametric studies were performed by using the verified FE model. The chord plastification failure of the T-joints was mainly found in both test and numerical studies. The relationship between the joint strengths and the variation of geometric ratios were investigated. The test and numerical strengths of the T-joints were used to assess the strength predictions by design equations provided in CIDECT, EN-1993-1-8 and the literature. It was found that these predictions generally provided unconservative predictions. A new equation that considers the effects of geometric ratios on the strengths was proposed based on both the test and numerical results. By adopting the newly proposed equation, the predictions are improved and provide the least scattered results when compared with other predictions.