The Precast/Prestressed Concrete Institute (PCI) sponsored a comprehensive research program to assess the capacity of headed-stud group anchorages. The PCI program was initiated in response to significant differences between headed stud design, as outlined in the PCI Design Handbook and the ACI 318 Building Code. Not covered by the PCI sponsored testing, but nonetheless important, were headed-stud groups located in thin or narrow members; that is, anchors embedded in a narrow member with two parallel free edges reducing the concrete breakout cone area. Tests of headed stud anchorage groups loaded in tension in this fashion are not extensively reported in the literature.
The test program herein, conducted by staff of Wiss, Janney, Elstner Associates, Inc. (WJE), was an in-house, unsponsored test program of 16 tension tests. Considered were the variables of embedment depth, edge distance, and spacing of the anchors parallel to the free edge. Test anchorages used one, two, and four headed studs in the connection. Transverse stud spacing, perpendicular to the edges, was also a secondary variable in this study. The results were compared to the present ACI 318-141, Chapter 17 provisions where two sides of the breakout surface are truncated. This paper provides a summary of the research work.
Tension Tests of Headed Stud Anchorages in Narrow/Thin Edge Members