Quasi-static test loading protocols for modular steel construction joints

Abstract

Owing to the different structural configuration of modular steel construction (MSC) joints compared with those in conventional structural frames, the existing loading protocols might not be applicable to MSC joints. Suitable loading protocols for MSC joints are therefore required for use in quasi-static cyclic tests, which is the focus of the present study. A representative three-dimensional MSC building was adopted in the numerical simulation programme. Dynamic analyses were carried out using the developed numerical model under a selection of seismic waves, from which the inter-storey displacements were obtained. The rainflow counting method was employed to process the obtained displacement–time histories, and the key parameters for the loading protocol, including the total number of cycles and maximum amplitude etc. were derived accordingly. A quasi-static cyclic loading protocol dedicated to MSC joints was subsequently established. The proposed loading protocol was compared with the existing loading protocols specified in ATC-24 and in FEMA-461 through numerical simulations. The examined loading protocols were applied to two typical MSC joints, and the numerical results indicated that the proposed protocol led to a small increment in the energy consumption, ductility and bearing capacity, in comparison with the two existing loading protocols. The results show that the existing and the proposed loading protocols are all deemed suitable for use in quasi-static cyclic testing of the MSC joints, and the proposed loading protocol with 37 cycles and 0.0158 rad loading peak value could provide a new and alternative loading program for the quasi-static test of MSC joint.