Headed steel stud anchors in composite structures, Part I: Shear

Abstract

The Newmark Structural Engineering Laboratory (NSEL) of the Department of Civil and Environmental Engineering at the University of Illinois at Urbana-Champaign has a long history of excellence in research and education that has contributed greatly to the state-of-the-art in civil engineering. Completed in 1967 and extended in 1971, the structural testing area of the laboratory has a versatile strong-floor/wall and a three-story clear height that can be used to carry out a wide range of tests of building materials, models, and structural systems. The laboratory is named for Dr. Nathan M. Newmark, an internationally known educator and engineer, who was the Head of the Department of Civil Engineering at the University of Illinois and the Chair of the Digital Computing Laboratory . He developed simple, yet powerful and widely used, methods for analyzing complex structures and assemblages subjected to a variety of static, dynamic, blast, and earthquake loadings. Dr. Newmark received numerous honors and awards for his achievements, including the prestigious National Medal of Science awarded in 1968 by President Lyndon B. Johnson. He was also one of the founding members of the National Academy of Engineering. Contact ABSTRACTThe current AISC Specification for Structural Steel Buildings (AISC, 2005a) is the lead specification for composite construction in the U.S. However, these provisions do not provide a recommendation for computing the strength of headed steel stud anchors (traditionally used as shear connectors) under tension or combined tension and shear. Headed stud anchors are subjected to these types of forces in composite structures such as infill walls, composite coupling beams, the connection region of composite columns, or composite column bases. While ACI 318-08 Appendix D (ACI, 2008) and PCI 6th Ed. (PCI, 2004) includes provisions for such conditions, those provisions are geared for more general anchorage conditions than are typically seen in composite construction. It would thus be beneficial to have design guidance specifically for the case of headed steel stud anchors subjected to tension or combined tension and shear in composite construction, evaluated within the context of the AISC Specification. In this work, different strength equations to compute the nominal tensile strength of a headed stud are reviewed and compared to experimental results. The resulting recommendations seek to ensure a ductile failure in the steel shank instead of a brittle failure within the concrete. Several criteria are proposed to ensure that a ductile failure controls in composite construction, and, different headed stud configurations and detailing reinforcement recommendations are proposed to improve the ductile behavior of headed stud anchors subjected to tension and combined tension and shear.

Design for Deconstruction for Sustainable Composite Steel-Concrete Floor Systems

“…8a. Similar to that observed for shear studs [4], the peak strength and ductility of the cyclic specimens are reduced, compared to the corresponding monotonic specimen (i.e., specimen 1-m24-c2-h). This is due to the reduction of the frictional coefficients at the slip planes, which is caused by smoothing of the contact surfaces during cycling, and the release of the bolt pretension, which is caused by the…”

Headed steel stud anchors in composite structures, Part II: Tension and interaction

“…The application of corresponding resistance factors of 0.75 or tension and 0.65 for shear (Pallarés and Hajjar, 2009) provides safe results for all tests.…”

“…The assessment of the accuracy of ACI 318-08 and PCI 6th is carried out through the computation of nominal values provided by the standards (using the steel formula and 5% fractile formula for concrete). The nominal shear strength of concrete, , in this work is predicted by pryout failure equations for the corresponding provisions as presented in Pallarés and Hajjar (2009). The nominal tensile strength of concrete, , is predicted by the minimum strength of pull-out and breakout strength presented in this work assuming uncracked concrete.…”

Modified Push-out Tests for Determining Shear Strength and Stiffness of HSS Stud Connector-Experimental Study

“…Research work of [14] has investigated on the static and fatigue testing on shear connector using push out tests. Re-cently, [15] have reported a comprehensive compilation of experimental studies on push-out specimens. It is reported that the equations given in [6] need modifications to comply with experimental trends.…”