Search

Post-installed bonded anchors are used extensively in practice but have not yet been incorporated into the design provisions of ACI 318-05, Appendix D. This paper presents a behavioral model that provides the basis for developing design provisions for anchorages to concrete using adhesive bonded anchors. The model is based on results of extensive numerical and experimental work. The behavioral model is compared with a worldwide database containing 415 tests on adhesive anchor groups, 133 tests of adhesive anchors located near a free edge, and accompanying baseline single anchor tests used to establish the relationship between the results of the group and edge tests and the behavior of isolated single anchors. The proposed model agrees very well with the tests on adhesive anchor groups, but is conservative compared to the tests with single anchors close to the edge.

This paper presents results of a comprehensive test program that investigated various factors with the potential to influence the bond strength of polymer-based adhesive anchors. 20 products from 12 manufacturers were included in the program for a total of 765 tests. To establish a reference bond strength, baseline tests were performed at room temperature for anchors installed in cleaned, dry holes. Individual factors were isolated through separate test series that maintained baseline conditions, except for the variable under consideration. The variables that were investigated included those that could be anticipated to occur during and after installation. Factors occurring during installation included the condition of the drilled hole, differences in the concrete strength, and differences in concrete aggregate. Factors occurring after installation included a short-term adhesive curing period and loading at an elevated temperature. This research demonstrates that reliable predictions of adhesive anchor performance are only practical by product-specific and condition-specific testing.

Adhesive (chemical) anchors are used frequently in both new construction and repair/retrofit projects. Current design codes do not contain rational design procedures for these anchors. An experimental program was undertaken to determine the behavior of these anchors and to develop a rational procedure for their design. The experimental program described in this study involved 97 tensile tests of 6 adhesive products on the following types of 5/8-in. diameter threaded anchors; fully bonded single anchors; partially bonded single anchors; and fully bonded anchor pairs. A behavioral model based on an elastic formulation is developed and assessed. Design recommendations for single and multiple adhesive anchors are presented in the paper.

This is an investigation for the design and behavior of single cast-in-place and retrofit concrete anchors under static, fatigue, and impact tensile loads. The embedment lengths used in this study were designed to produce ductile behavior, which was defined as steel failure of the anchor shank. Anchor types tested were cast-in-place anchor bolts and embeds and four types of retrofit anchors: adhesive; grouted; expansion; and undercut. The study compared the design, load deflection behavior and mode of failure of retrofit concrete anchors with that of cast-in-place anchors under different tensile loading conditions. Behavior modes of anchors were identified under static, fatigue, and impact tensile loads, and anchor types were categorized according to these behavior modes.