Experimental research on the in-plane performance of discontinuous modular diaphragms

Abstract

Modular steel buildings (MSBs) are assembled from factory-manufactured modules and have been becoming more popular with higher construction efficiency. However, MSBs show quite different in-plane load-transferring behavior from traditional steel frame structures due to the diaphragm discontinuity, and in-depth researches will be needed to acquire better knowledge of its structural behavior. In this paper, the in-plane performance of modular diaphragms was investigated through the half-scaled experiments on the assembled modules, with two types of horizontal connections and double-layer diaphragm structure being taken account. The load–displacement curves, the displacement distribution as well as the strain development were all analyzed and the effects of different horizontal connections as well as double-layer diaphragm on the in-plane performance of diaphragm were discussed. Afterwards, one analytical model will be proposed to evaluate the in-plane transferring ability of modular diaphragms, where two key parameters are defined including displacement inconsistency factor (DIF) and effective lateral stiffness (ELS). The results from experiments and analytical models indicated the modular diaphragms were far from rigid floor assumption and the horizontal connections could make great differences in in-plane load transferring ability of modular diaphragms.