Experimental analysis of semi-rigid boltless connectors

Boltless semi-rigid connections are used in the storage rack industry. The connectors consist of end plates welded to each end of a beam and an interlocking arrangement to engage with perforated columns, hence supporting the beams and restraining the columns. There are a variety of types and designs in use, characteristic of different rack manufacturers. In the absence of theoretical approaches, currently the only way to determine the properties of such joints is by testing. The aim of this paper is to determine the parameters governing an efficient beam end connector design. The paper includes an appraisal of commercially available beam end connectors and attempts to classify the connectors based on their special features. The paper presents the results of the tests carried out on a selected number of connectors and compares their moment-rotation characteristics, as well as their deformation modes using stress-sensitive lacquer. A theoretical investigation is carried out to estimate the influence of the flexibility of the beam and the column used in the tests on the stiffnesses determined experimentally. The effects of dimensional changes on moment-rotation characteristics are considered, and the main parameters controlling the behaviour of beam end connectors are discussed.