A fracture mechanics based description of the pull-out behavior of headed studs embedded in concrete

Determining the Effect of Rock Strength Parameters on the Breakout Area Utilizing the New Design of the Undercut/Breakout Anchor

“…The operation of the new anchor is different from the previous undercutting anchors due to a different mechanism of load transfer to the rock mass (breaking of the rock near the bottom of the hole as a result of the expansion of the anchor elements and the lack of support on the free surface), as shown in Figure 1. Supports, in the previous solutions, were necessary to pull out the anchor and could affect the distribution of stresses in the rock, in the zone of anchor action [22,34,[49][50][51]. The proposed solution for realizing the destruction of the rock medium structure eliminates these effects.…”

“…These methods, in combination with experimental studies, enable research towards a detailed understanding of the actual behavior of engineering structures for further optimization [18][19][20][21]. The research to date has been predominantly focused on the efforts to understand concrete failure mechanisms [22,23], developing anchor load capacity estimation methods [24,25], the impact of their design on the pull-out force [26,27], and the impact of the technological parameters of anchorage systems [28,29] on anchor capacity to carry certain loads, including the reach of the breakout area on the free surface of the concrete. The authors of the presented concept of using anchors in mining technology as a method of rock mass separation have conducted many studies aimed at determining the usefulness of the method, estimating the pull-out force, and defining potential areas of its application [30][31][32][33].…”

“…By reason of the large discrepancies between the theoretical and the empirical failure modes in relation to the elastic linear and the non-linear fracture mechanics, a number of models have been proposed in order to solve the estimations of the load capacity of anchorage (the pull-out force), and the extent of the breakout area on the free surface (e.g., Eligehausen [22], Piccinin [39], Brincker [7]).…”

“…The problem has been successfully solved [52], however, at the current stage the application of additional, own, complex calculation procedures are required. To date, the aim of the research on undercutting anchors [22,24] has been to determine the pull-out force of the anchor at specified installation conditions (i.e., anchor load) or to determine the strength of the concrete in the resulting engineering structure (pull-out test). In the pull-out test method, the anchor is embedded in a hole made in the concrete and then pulled out using a special device based on the free surface of the concrete structure.…”