12.22: Seismic performance of high capacity hybrid beam‐columns: Comprising of high strength steel tubes subjected to lateral cyclic loading

Abstract

High strength and ultra-high strength materials are widely used in industrial applications significantly increasing the load bearing capacity and reducing the overall weight and cost. The present study continues a series of experimental investigations on innovative fabricated hybrid sections consisting of high strength steel tubes welded to mild steel plates. This type of innovative section is proposed with the aim of promoting the application of high and ultra-high tensile steel in construction, taking advantage of the load-bearing capacity of these materials along with the coupled effect of ductile mild steel plates. Large-scale hybrid columns are tested under a combination of axial load and lateral cyclic load using a multi-axis substructure testing (MAST) facility. Lateral cyclic loadings are applied along with constant axial loads of which the hysteretic curves are obtained for various grades of steel tubes, namely, mild steel tube (grade 300), high strength steel tube (grade 800) and ultra-high strength steel tube (grade1200). Test results are analysed to examine the seismic performance of these proposed innovative sections and obtain the combined axial and lateral cyclic capacities, drifts, strains and plastic hinge distributions along the beam-columns. The effect of tube material is considered and the axial shortening observations are compared to constant compression. The experimental outcomes of this paper can be incorporated in nonlinear modelling of structures consisting of ultra-high strength steel tubes.

Lateral Cyclic Performance of Hybrid Fabricated Beam‐Columns

“…Using the developed nonlinear material behaviour for mild steel and HSS tubes, a predictive FE model was generated for the cyclically loaded hybrid beam-column and validated against the available experimental results [18]. The boundary conditions of the FE model were simulated to replicate the test conditions.…”