Testing of wire-laser additively manufactured (WLAM) I-section stub columns with various stiffener configurations

Wire-laser additive manufacturing (WLAM) is an additive manufacturing technique to fabricate metal components, using metal wires as the raw material and laser as the energy source. It is capable of producing sections with complex shapes. However, knowledge about WLAM structural components is lacking, and investigation on their geometric characteristics and structural behavior is limited. This paper presents an experimental study on the compressive behavior of WLAM ER110S I-section stub columns with various stiffener configurations; this concept makes full use of the characteristic of high geometric freedom provided by additive manufacturing. The experimental program comprised 4 tensile coupon tests and 13 stub column tests, with the geometric characteristics of all specimens captured via 3D laser scanning. Their failure modes and ultimate loads are comprehensively discussed in this paper. The obtained test data were then used to evaluate the applicability of relevant design rules in EN 1993-1-1, the Direct Strength Method, and the Continuous Strength Method for WLAM ER110S I-section stub columns. The findings revealed that all design methods provided reasonably accurate strength predictions for WLAM ER110S I-section stub columns, although all three methods provided unsafe unfactored predictions for some slender I-section specimens. Moreover, compared to WLAM ER110S conventional I-section stub columns, the stiffened I-section specimens exhibit clearly enhanced structural efficiency when the flange-tip stiffener length exceeds one-fifth of the flange outstand width, achieving a disproportionate increase in both load-bearing capacity and deformability relative to the added mass. These findings offer insights into structural strengthening and retrofitting via metal additive manufacturing.