Anchorage to Concrete Design: The Transition from Tabular Load Capacity to Rational Design and Anchor Qualification Procedures to Manage Risk Neal S. ANDERSON V. Pres. of Engineering Concrete Reinforcing Steel Institute Schaumburg, Illinois, USA nanderson@crsi.org Neal S. Anderson, born 1962, received his BS and MS degrees in civil engineering from Purdue University, West Lafayette, Indiana. He has been involved with concrete anchorage research, focusing on cast-in, headed stud anchors, and rational design methods. Donald F. MEINHEIT Affiliated Consultant Wiss, Janney, Elstner Associates, Inc. Chicago, Illinois, USA dmeinheit@wje.com Donald F. Meinheit, born 1943, received his BS from Purdue University, MS from the University of Illinois, and PhD from the University of Texas at Austin, all in civil engineering. He is chairman of ACI Committee 355, Anchorage to Concrete. Summary Anchorage to concrete design has progressed considerable in the past 10 years. Provisions now exist in the ACI 318 Code for designing cast-in and post-installed expansion anchors. No other US code has provisions that are as detailed as those in ACI. Other code bodies, AASHTO and AISC are currently lacking in specific code language for designing anchors that are embedded in concrete. This brief paper describes some of the history and important milestones in developing the current provisions in ACI 318. It is not the intent that this be a complete history of anchorage to concrete design but a review of the positive and negative aspects in the development of the current (2008) design provisions. Keywords: concrete anchorage, post-installed, cast-in, adhesive, ACI Appendix D, concrete capacity design (CCD) method. 1. Introduction Since the mid-1980s, the design of anchors embedded in concrete, whether cast-in or post-installed, was generally by allowable stresses, manufacturers’ catalog values, and / or a design model based on shear-punching failure concepts. Research starting in the late 1970s and continuing to the present has been used to calibrate design models that can predict the tension and shear capacity of cast-in anchors, post-installed mechanical expansion anchors, adhesively bonded anchors, and concrete/masonry screw anchors. This discussion reviews the history of anchorage design development in the United States. In particular, the development of qualification procedures for certain anchor types is discussed. 2. Anchorage to Concrete - The Codified Times In the 2002 Edition of the ACI Building Code (ACI 318-02), anchorage design provisions were finally codified into one document. The ACI 318 Appendix D provisions are based on the Concrete Capacity Design (CCD) method, which was an adaptation of the original European Kappa Method proposed in Germany in the late 1980’s. The CCD method was moulded into ACI Code Provisions, based on successful use of the design provisions in Europe. Placing anchorage requirements in the ACI Code was motivated by a need to rationally design post- installed anchorages, that is, anchorages installed in hardened concrete; cast-in anchors, including headed studs and bolts, were also incorporated into the design provisions. Appendix D provides the designer with a transparent means to perform anchorage design and incorporates a rational procedure for computing a minimum design capacity based on capacity at essentially first cracking. 418 17TH CONGRESS OF IABSE, CHICAGO, 2008