scope:

This report has been prepared by members of the ACI 349 Sub-committee on Steel Embedments to provide examples of the application of the ACI 349 Code to the design of steel embedments. The ACI 349 Committee was charged in 1973 with preparation of the code covering concrete structures in nuclear power plants. At that time, it was recognized that design requirements for steel embedments were not well defined and a special working group was established to develop code requirements. After much discussion and many drafts, Appendix B was approved and issued in the 1978 Supplement of ACI 349 covering the design of steel embedments. Subsequently, the Sub-committee has continued to monitor on-going research and testing and to incorporate experience of applying the Code. Periodic revisions have been made to the Code and Appendix B.

The underlying philosophy in the design of embedments is to attempt to assure a ductile failure mode. This is similar to the philosophy of the rest of the concrete building codes wherein, for example, flexural steel for a beam is limited to assure that the reinforcement steel yields before the concrete crushes. In the design of an embedment for direct loading, the philosophy leads to the requirement that the concrete pull-out strength must be greater than the tensile strength of the steel.

This report includes a series of design examples starting with simple cases and extending to more complex cases for ductile embedments. The format for each example follows the format of the Strength Design Handbook, SP-17, and provides a reference back to the code paragraph for each calculation procedure.