Membrane residual stresses and local buckling of S960 ultra-high strength steel welded I-section stub columns

Abstract

The membrane residual stresses and local buckling behaviour of S960 ultra-high strength steel welded I-section stub columns have been investigated through a comprehensive testing and numerical modelling programme. The testing programme included material testing, membrane residual stress measurements, initial local geometric imperfection measurements and sixteen stub column tests. On the basis of the measured data, a membrane residual stress predictive model was developed. Following the testing programme, a numerical modelling programme was conducted, where finite element models were firstly developed and validated against the test results and then adopted to conduct parametric studies to generate further numerical data. The obtained test and numerical data were used to assess the applicability of the relevant design provisions for S700 (or S690) high strength steel welded I-section stub columns, as given in the European code, American specification and Australian standard, to their S960 ultra-high strength steel counterparts. The assessment results generally revealed that (i) all three sets of codified slenderness limits can be accurately and consistently used for cross-section classification of S960 ultra-high strength steel welded I-section stub columns and (ii) the local buckling design provisions in the three design codes also lead to accurate and consistent cross-section compression resistance predictions.