Innovative hollow section column‐splice connections resorting to laser cutting

Abstract

1 Introduction Over the past few decades, researchers and engineers have tried to explore different possibilities to implement hollow sections in structural applications, to utilize their interesting resistance against high axial forces and bending in all directions [1], for lightweight structures [2], with lesser requirement of fire protection materials [3], high resistance under wind-, water-or wave-loading scenarios [4] and excellent aesthetics. However, in order to achieve that goal, suitable beam-to-column or column-to-column connections are necessary between tubular elements. To make such connections easier, an innovative "passing-through" concept was proposed in the EU-RFCS research project-"LASTEICON" (RFCS-GA-709807) [5] where several "passing-through" tubular connections were developed using laser cutting technology (LCT) and investigated with the primary aim to reduce and possibly avoid the local distortions and premature flange fractures occurring in the conventional or existing tubular joint typologies together with a reduced welding quantity. The basic concept behind the passing-through joints are shown in Fig. 1. LASTEICON mainly focussed on different beam-to-CHS column connections consisting of "main" (primary) beams connected to the CHS column via one or multiple "through" elements (I-beam stub element or individual steel plates) passing through laser-cut slots on the CHS column. Thanks to their several advantages, both structural and economical, evi-denced by experimental and numerical research investigations , the LASTEICON "passing-through" connections proved to be a viable alternative, and was therefore extended to a new European research project-"LASTTS" [6], where novel, specialised, and more complex joints were proposed to be investigated. Hollow section column-or beam-splice connections are deemed to be one of the important research aspects for project "LASTTS". This article presents three different types of joint configurations designed and analysed for the laser-cut innovative splice connections applicable for CHS members. The different types of configurations are described below followed by the adopted modelling technique , boundary conditions as well as the numerical para-metric studies. Relevant conclusions have been presented ORIGINAL ARTICLE Abstract Circular Hollow Section (CHS) columns are highly encouraged in the modern industry due to their good resistance against high compression, tension and flexure in all directions, combined with their exceptional aesthetics. However, conventional end plate-bolted column-splice connections tend to limit the full potential of the CHS by focusing most of the damages in the bolts and sometimes discourage architects with a poor aesthetic. An innovative "passing-through" concept (using laser cutting technology) have therefore been proposed in the EU-RFCS project LASTTS to develop efficient column-splice connections. Three different configurations have been presented in this article: (1) CS-1: CHS columns connected using passing-through steel plates, bolts and steel cover plates outside the tube diameter; (2) CS-2: CHS columns connected using passing-through steel plates, bolts and steel cover plates inside the tube diameter; (3) CS-3: CHS columns connected using passing-through steel plates, bolts and steel end plates inside the tube diameter. Nonlinear para-metric studies have been conducted based on finite element models, calibrated from a previous experimental campaign, to understand the influence of each parameter and subsequently characterize the analytical assumptions to calculate their ultimate resistance under different loads. Additionally, they are compared among each other to note their advantages/disadvantages in terms of strength, stiffness and industrial application.