Description
ACI 349 Appendix B was developed in the mid 1970s following review of design methods and available test data. Since that time there has been extensive additional test data. In 1992, a task group was formed to compare the Appendix B methodology to that of the Concrete Capacity Design (CCD) Method for all available tests results. The review indicated that concrete breakout failures were predicted better (for example, for bolt groups, and edge conditions) by the new prediction equations in the Concrete Capacity Design Method than by the design method of Appendix B. After extensive review, ACI 349 chose to incorporate the Concrete Capacity Design Method to improve the requirements of the previous Appendix B.
Therefore, Appendix D of ACI 349 was developed to better define the design requirements for steel embedments. Revisions are periodically made to the code as a result of on-going research and testing. As with other concrete building codes, the design of steel embedments attempts to assure a ductile failure mode so that the embedment reinforcement yields before the concrete fails. In embedments designed for direct [or tensile] loading, the concrete pullout strength must be greater than the tensile strength of the steel. This report presents a series of design examples of ductile steel embedments. These examples have been updated to include the revision incorporated in Appendix D of ACI 349-06.
Keywords: Anchorage (structural); anchor bolts; anchors (fasteners); concrete capacity design (CCD); embedment; inserts; load transfer; studs.
Table of Contents
Introduction
Notation
Commentary
PART A—Examples: Ductile single embedded element in semi-infinite concrete
Example A1—Single stud, tension only, no edge effects
Example A2—Single stud, shear only
Example A3—Single stud, combined tension and shear
Example A4—Single bolt, combined tension and shear
PART B—Examples: Ductile multiple embedded elements in semi-infinite concrete
Example B1(a)—Four-stud embedded plate, tension only, wide spacing
Example B1(b)—Four-stud embedded plate, tension only, close spacing
Example B1(c)—Four-bolt surface-mounted plate, tension only, close spacing, close to a corner
Example B2(a)—Four-stud embedded plate, combined shear and uniaxial moment
Example B2(b)—Four-anchor surface-mounted plate, combined shear and uniaxial moment
Example B3—Four-threaded anchors and surfacemounted plate, combined axial, shear, and moment
Example B4(a)—Four-stud embedded plate in thin slab, tension only
Example B4(b)—Four-stud rigid embedded plate in thin slab, tension only
APPENDIX A—Tables
Table 1—Materials for headed and threaded anchors
Table 2—Threaded fastener dimensions
Table 3—Required embedment for ductile behavior: free field, single anchor
Table 4—Anchor head and nut dimensions
Table 5—Hardened washer dimensions
Table 6—Stud dimensions
APPENDIX B—ACI 349, Appendix D, Code and Commentary