Testing and analysis of different hold down devices for CFS construction

This paper summarizes the findings of a two-phase study on hold down devices used in cold formed steel (CFS) structural systems. The first phase consisted of component testing and numerical analysis of hold down devices while the second phase was based on testing of CFS framed sheathed wall panels under cyclic lateral loading. Eleven monotonic and three cyclic tensile load tests were performed on seven different types of hold down devices to assess the performance of readily available hold downs and propose new hold down geometries that employ hot rolled angle sections. Tests revealed that some of the hold down devices that have been used in CFS construction exhibited very poor behavior with significant deformation under loading. The experimentally observed deformation mode of all hold down device types was correctly captured by the finite element models. Experimental and numerical findings proved that a superior performance in terms of strength and stiffness can be obtained from a simple hold down device that is manufactured from a steel angle section. In the second group of tests, the proposed angle section geometry was further studied as part of oriented strand board (OSB) sheathed CFS framed wall panels that were subjected to cyclic lateral loading. Close agreement was observed between the wall panel test results and those obtained from the hold down assembly tests. Wall panel test results indicated that the angle type hold down device has adequate mechanical performance to develop the expected strength of OSB sheathed CFS framed wall panel.