The experimental investigation of a crack's influence on the concrete breakout strength of a cast-in-place anchor

Actual model tests are carried out to investigate the influence of a crack on the concrete breakout strength of an anchorage and to examine the appropriateness of the various criteria that are available for an anchorage design in a new nuclear power plant and the anchorage capacity evaluation in the currently operating nuclear power plants in the case where various types of cracks already exist in the anchorage. These tests are intended for the cast-in-place anchor which is widely used for the fastening of equipment in Korean nuclear power plants. One hundred and five plain concrete test specimens are manufactured on the basis of ASTM E488 containing 21 cracked conditions. The principal test variables chosen are related to the crack properties including, the crack width, the crack depth and the distance between the crack and the anchor. In order to apply a tensile force, a 100 tonnes-capacity actuator is used with a displacement control of 0.5 mm/min. It is proven that the ACI 349 code, CEB-FIP code and SQUG GIP are conservative in a comparison with the test results. Some improved proposals are suggested on the basis of the test results in order to accurately take into account the influence of the crack in the anchorage capacity evaluation.