Abstract: A pure fixed-head ~zero-rotation! condition at the top of a group of laterally loaded piles is seldom achievable in the field, Rh
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even when piles are installed in a group that is ‘‘rigidly’’ constrained by a stiff concrete pile cap. Assuming complete fixity during design E1Q#@*rX>
~zero rotation at the pile head! can result in underestimated values of pile-head deflection, and incorrect estimates of the magnitude and G
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the location of maximum bending moments. A simple and practical approach is presented for estimating the moment restraint that is c0&! S-4M
provided by the pile cap at the top of a pile group. The moment restraint, represented by the rotational restraint coefficient (KMu), serves LXrk5>9
as a boundary condition for analyzing groups of laterally loaded piles. Full-scale field tests performed on two pile groups with concrete (0_zp`)
pile caps show that the proposed method for estimating rotational restraint provides results that are in good agreement with measured field u` (yT<>H
performance.
