Testing and numerical modelling of S960 ultra-high strength steel angle and channel section stub columns

Abstract

An extensive experimental and numerical study of the cross-sectional compressive responses and resistances of press-braked S960 Ultra-High Strength Steel (UHSS) angle and channel section stub columns is reported in this paper. The experimental analysis was conducted on four equalleg angle sections and eight plain channel sections along with comprised material testing, initial local geometric imperfection measurements, a total of 18 stub column tests. The full experiment setups, procedures and key observations were thoroughly presented in this report. The experimental analysis was later augmented by Finite Element (FE) simulation programme, where FE models were first created to replicate the experiment structural responses and then utilised to develop further numerical data over various cross-section sizes. However, the current global standards established in America, Australia, Europe, and New Zealand only cover the design of structure members with material grades up to S700, leading the examined S960 UHSS angle and channel section stub columns out of scope of the existing design standards. In this research, the experimentally and numerically obtained data was implemented to assess the applicability of the codified formulations and provisions to the design specifications of S960 UHSS angle and channel section stub columns. The computation results generally indicated that the current Eurocode results in overall consistent and precise predictions of cross-section compressive resistance, however it has greatly overestimated the predicted resistances for S960 UHSS channel section stub columns; whilst the American and Australian/ New Zealand standards excessively generate scattered design cross-section compressive resistance with unsafe and over conservative predicted resistances for S960 UHSS channel section and slender angle section stub columns. A revised codified design standard was proposed in this report, which shown to yield a consistent, precise, and safe design cross-section compressive resistance for S960 UHSS angle and channel section stub columns.