MULTIPLE BOLT ANCHORAGES: METHOD FOR DETERMINING THE EFFECTIVE PROJECTED AREA OF OVERLAPPING STRESS CONES.

Abstract

To determine the resistance concrete offers to tensile pull-out, the concept of the stress cone has been developed. The calculation of the concrete's resistance to pull-out is accomplished by applying a nominal concrete stress to the horizontal projected area of the potential failure cone. When anchors are placed closely enough together that their individual stress cones overlap, calculation of the effective projected area becomes more difficult. For this reason a 'building block' approach has been developed for determining these areas. This paper outlines area calculations in five methods that can be used collectively to estimate the effective projected area of a multi-bolt anchorage.