Designers of steel and precast column-foundation connections commonly use cast-in-place headed anchors. These connections can be divided into two categories: those governed by axial force transfer and those governed by moment transfer. For column-foundation connections governed by axial load transfer, two different design methods have been used: 1) anchoring-to-concrete provisions considering concrete breakout, and 2) punching shear. For connections governed by moment transfer, three different design methods have been used: 1) anchoring-to-concrete provisions considering concrete breakout, 2) the strut-and-tie method, and 3) the joint shear design method. For a given connection, the results obtained from these methods can differ by up to an order of magnitude. Multiple full-scale and half-scale laboratory tests were performed to investigate the suitability of these design methods. Experimental test results indicate that for connections governed by axial force transfer, the punching shear case has a higher capacity than the breakout case, consistent with current code provisions from ACI 318-14. For connections governed by moment transfer, the concrete breakout equations of ACI 318-14 seem to be appropriate, while alternative methods can be unconservative. This paper documents the various design methods used in practice, the test specimen results, and the implications for the design of steel-column-to-concrete-foundation connections.
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