Research On Shear Behavior And Design Method Of Self-Tapping Screw Connecting

Mechanical connection is one of basic types of the steel structure connections. Self-Tapping Screw connection is one efficiency type of mechanical connection. In the connections of lightweight steel structures, self-Tapping Screws are widely used due to the advantages of economy, convenience and efficient installing compared with traditional bolt connecting when connecting moderate and thin thickness steel plates, (thickness≤6mm).Self-Tapping Screw connections is a kind of commonly used Shear Connection. Experimental researches on characteristics of connections between profiled steel sheet and other structural elements (including profiled steel sheet, first floor supporting structural element or shear connectors) are extensive proceeded since 1950s. However, of all the tests, the used profiled steel sheet is so thin and the high strength of Self-Tapping Screw that all the failure modes are bearing failure of profiled steel sheet without developing the strength of Self-Tapping Screw. The experimental data can not be used in designing the Self-Tapping Screw connected moderate or thin thickness steel plates. In this dissertation, the shear behavior of single- sided and double-sided Self-tapping Screw is tested; the shear performance and the design method of shear bearing capacity are studied. The main contents include:According to the demands of experiment, a set of safe, practical and accurate loading device and displacement measurement equipment is designed.Referring to the basic failure pattern of the Self-tapping Screw connections and the test equipment of this test, specific form and size of the members which are connected by Self-tapping Screws are determined.Tests on shear resistance behavior of 89 Self-Tapping Screw of double-sided shear members and 68 single-sided ones are carried out. Throughout the test, the applied load N when the Self-tapping Screw connections fails and the displacementδof the Self-tapping Screw connected joint under load N are obtained. Meanwhile the experimental survey and results record are carefully taken.From the test observation and results, the development of shear stress and the failure modes of double-sided and the single-sided Self-Tapping Screw connections under shear stress are analyzed. Experimental data are used to regress a new design method of single Self-Tapping Screw connected moderate and thin thickness steel plates; relevant structure requirements and construction requirements of the Self-tapping Screw connections in shear are suggested.