Nonlinear Spring Modelling Approach for Concrete Edge Breakout Failure of Shear Loaded Anchorages

Abstract

The failure 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 current design provisions for such anchorages are limited in their scope to rectangular and maximum of 3 × 3 anchor patterns. This paper provides an overview of a new nonlinear spring modelling approach for the realistic evaluation of shear loaded anchorages of arbitrary configurations in the case of concrete edge failure that can overcome several of the current design limitations. The model follows a displacement-based approach and was developed based on the evaluation of a comprehensive experimental study carried out on shear loaded anchorages of various configurations. To account for a realistic force distribution among the anchors of the group, the anchor behaviour is modelled with nonlinear springs and nonlinear static analysis is performed. The nonlinear anchor spring properties consider the influence of adjacent anchors, multiple anchor rows and vicinity of further edges through a new tributary volume approach, and any hole clearance and crack patterns are accounted for. The accuracy of the model, and postulates used in the model are validated against experimental tests on different shear loaded anchorages. The validity of the model is shown by comparing the results of tests and nonlinear spring model.