This dissertation presents the results of an analytical and experimental investigation of the fracture mechanisms of short anchor bolts embedded in concrete and loaded monotonically in tension.

In the mathematical analysis the anchor is modeled by a rigid unbonded plate in a vertically loaded elastic half-space. Symmetric cracks extending from the edges of the anchor are included to model the cracking which develops during the tests. By using a Green's Function approach together with complex variable techniques the elastostatics problem is reduced to solving a system of coupled singular integral equations. Stress fields and stress intensity factors are obtained after numerically solving the integral equations. The stress intensity factors are used to construct crack paths, to determine the stability of crack propagation, and to obtain the tensile capacities of the anchor bolts.

The results of the mathematical analysis are compared to experimental results obtained from two dimensional pull-out tests performed on anchors embedded in mortar specimens. It is shown that fracture mechanics can be used to eliminate the geometry dependence currently observed in the calibration curves for pull-out testing systems, and to predict the tensile capacity of short anchor bolts.

Finally, a non-linear fracture model which can be incorporated into the linear model to improve on the predictions is also presented.