Experimental investigations on the concrete edge failure of shear loaded anchor groups of rectangular and non-rectangular configurations

Abstract

The failure mode of anchorages placed close to the concrete edge and loaded in shear perpendicular towards the edge is often governed by the concrete edge breakout failure. The design provisions for concrete edge failure given in the current codes are limited in their application for anchor groups with rectangular anchor configurations only. The number of anchors in a row is limited to three for anchorages without, two for anchorages with hole clearance. Furthermore, for anchor groups with multiple anchor rows loaded in shear perpendicular and towards the edge, the failure load may be calculated by assuming the failure crack originating from the front anchor row (EN 1992-4) or from the back anchor row (fib Bulletin 58, ACI 318). The aim of this experimental study was to investigate the behaviour of shear loaded anchor groups of rectangular, triangular and hexagonal configurations undergoing concrete edge failure. A comprehensive experimental program was carried out on single anchors and anchor groups of different configurations to obtain information on (i) the group behaviour, (ii) the crack initiation and propagation, (iii) the influence of the displacement behaviour of single anchors on the behaviour of anchor groups and (iv) the influence of hole clearance pattern. The testing concept, test setup and the detailed evaluation of the test results such as load-displacement curves of the groups, load-displacement curves of single anchors, measurements on the hole clearance pattern and the investigation of the crack pattern and failure mode are discussed in this paper. Based on the evaluation of the test results presented here, a new analytical model is being developed for the concrete edge failure mode of shear loaded anchor groups that will be presented in a future paper.