Title: Straight Talk About Anchorage to Concrete--Part I

Author(s): Robert W. Cannon

Publication: Structural Journal

Volume: 92

Issue: 5

Appears on pages(s): 581-586

Keywords: anchors (fasteners); anchorage (structural); bolts ; concretes; compressive strength; embedment; expansion; failure; rock bolts; studs; splitting tensile strength; Design

DOI: 10.14359/913

Date: 11/1/1995

Abstract:
There is a considerable amount of debate within the current ACI community concerning the direction to be taken with respect to code requirements for anchorage to concrete. This debate stems from philosophical differences in the approach to the design of anchorages, as adopted in the European community, and contained in the only existing ACI Code dealing with the subject; Appendix B of the ACI 349 Code for Nuclear Safety-Related Concrete Structures. This debate is further intensified by differences in the U.S. and Europe regarding testing embedments deeper than 10 in. This paper is presented in two parts, and is primarily concerned with the tensile pullout capacity of anchors that fail concrete, since this is the design basis for anchorage. It discusses basic differences in philosophy and the factors contributing to the philosophical differences. It also discusses the relationship between confinement and development of anchorage capacity and the relationship between the splitting tensile strength of concrete and the upper- and lower-bounds of test data over the full range of embedments. Part I deals primarily with U.S. data for headed and undercut anchors. Part II deals with different types of expansion anchors and data from both the U.S. and Europe. Spreadsheet graphics have been incorporated to examine data from more than 2000 tests, with respect to individual and multiple anchor capacities and the effects of reduced confinement on different types of anchors by the proximity of anchors to free surfaces.