Weld Effective Section Moduli for CHS Moment T-connections

Abstract

An experimental program was developed to test various unreinforced circular hollow section (CHS)-to- CHS 90° T-connections subject to branch in-plane bending moment with the objective of determining the effective section moduli of the welded joints. Twelve specimens were designed to be weld-critical (i.e., to fail by weld rupture), and tested by applying a single quasi-static point load, laterally, to the top of each branch. An equation for the weld effective section modulus for CHS-to-CHS moment T-connections is developed, and various design formulae are assessed through first-order reliability analysis. The scope of this research covers fillet and partial-joint-penetration groove welded connections with 0.31 ≤ branch-to-chord width ratio (β) ≤ 0.91 and 31 ≤ chord slenderness (D/t) ≤ 46, to illustrate the influence of these key parameters (as well as weld type) on flexural strength. Recommendations are made for weld design using the “effective length approach” in conjunction with AISC 360 and CSA S16.