Effect of connection details on the cyclic behavior of nestable screw sidelaps

摘要

The connection strength and stiffness sensitivity of screwed sidelaps in nestable steel decks to screw installation details has been experimentally explored via cyclic testing. The cyclic behavior of sidelaps has been recently incorporated in the high fidelity modeling and seismic evaluation of the steel deck diaphragm in rigid wall - flexible diaphragm buildings, where "unzipping" a sidelap (loss of a significant number of sidelap connections along a deck edge) could significantly reduce the seismic performance of the whole diaphragm. A total of 24 monotonic and cyclic sidelap tests have been performed in the Thin-Walled Structures Laboratory at Johns Hopkins University. Two different screw edge distances, three different deck thicknesses (i.e. 18 gauge 20 gauge, and 22 gauge), and two different screw sizes were included in the test matrix. The screws were installed either "close to the edge" or "far from the edge". For the "close to the edge" condition the typical 1.5d edge distance limitation in the design specification was not satisfied. Both monotonic and cyclic test results show that the strength of the sidelap connection can be correlated to edge distance and screw installation details. A maximum 25% and 19% difference in the ultimate strength of the screw sidelaps were observed in monotonic and cyclic tests, respectively. The rest results were compared to sidelap strengths in the literature, and potential changes to sidelap strength predictions and installation methods are discussed.