Moment resistance of blind-bolted SHS column splice joint subjected to eccentric compression

Abstract

A new type of splice joint for Square Hollow Section (SHS) columns has been introduced in this paper. The spliced SHS columns are bolted to an inner sleeve which fits snugly to the internal surfaces of both columns. The moment resistances of such joints are studied analytically and experimentally. Under bending moment, the bearing interaction between the columns and the inner sleeve forms the Lever-Hold Effect which contributes to the moment resistance of the spliced joint. The mechanism of the Lever-Hold Effect can be simplified as the failure problem of a “semi-infinite” plate. It is found that the yield line method tends to overestimate the bearing capacity of the “semi-infinite” plate due to false yield line pattern and will result in overestimation of the contribution from the Lever-Hold Effect. To solve this issue, a revised yield line pattern is proposed in accordance with the forming process of yield lines on the “semi-infinite” plate. Numerical analyses and experimental study on the moment resistance of the joints have been carried out to validate the proposed analytical pattern. Based on the FEM analyses and test results, the formulae to estimate the moment resistance of RHS column splice connection with inner sleeves are proposed.