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

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.

Push-Out Tests on Large Diameter and High Strength Welded Stud Connectors

“…Accordingly, the shear strength of large diameter and high strength welded Advances in Civil Engineering stud connectors could also be accurately estimated by AASHTO LRFD [19] as the conventional welded stud connectors. Since the failure modes of the push-out tests are the stud shank fracture without the splitting of the concrete blocks, the shear strength of welded stud connectors could be regarded as the tensile strength of the studs, which is also veri ed by Pallarés and Hajjar [4,5] in the research of welded stud connectors with conventional diameters.…”

“…Lam [3] performed 72 static push-out tests on welded studs to determine the shear strength of welded stud connectors embedded in hollow-core slabs. Pallarés and Hajjar [4,5] reviewed a large number of push-out and pull-out tests on welded stud connectors and proposed formulas for the limit states of welded stud connectors subjected to shear force, tension force, and combined tension and shear force. Lin et al [6] also investigated the behavior of welded stud connectors subjected to combined tension and shear loads, and an improved shear-tension interaction strength equation was recommended.…”

08.13: Structural performance assessment of steel frames with reinforced concrete walls

“…In 2010, the AISC [23,24] has included the results from the extended research conducted by Pallares and Hajjar [25,26] on headed steel stud anchors as a force transfer mechanism in composite constructions, including composite wall systems. The capacity of a single headed stud can be calculated by the following equation for studs governed by steel shank failure…”

Shear-Tension Interaction Strength of J-Hook Connectors in Steel-Concrete-Steel Sandwich Structure

“…The most critical scenario is that they are subjected to combined shear and tension as in the case of connections between the tension members and sandwich deck as shown in Figure 2a; connections between the horizontal beams and shear walls as shown in Figure 2c and 2d; high shear region of the beam and slab, and sandwich structures subjected to impact and blast as shown in Figure 2e and 2f. The shear resistance of the headed shear stud connectors in the steel-concrete composite structures has been extensively studied by Viest [9], Driscoll and Slutter [10] [29], Klinger and Mendonca [30], and Pallarés and Hajjar [31]. The resistance of the anchorage under combined shear and tensile load was studied by Pallarés and Hajjar [31], McMakin et al [32], Sari et al [33], and Mirza and Uy [34].…”

“…The shear resistance of the headed shear stud connectors in the steel-concrete composite structures has been extensively studied by Viest [9], Driscoll and Slutter [10] [29], Klinger and Mendonca [30], and Pallarés and Hajjar [31]. The resistance of the anchorage under combined shear and tensile load was studied by Pallarés and Hajjar [31], McMakin et al [32], Sari et al [33], and Mirza and Uy [34]. From these literatures, it can be found that most of these experimental and numerical studies were carried out on headed studs to investigate their resistances against tension and shear forces as well as combined shear and tensile forces.…”