Abstract: A pure fixed-head ~zero-rotation! condition at the top of a group of laterally loaded piles is seldom achievable in the field, 4Xn-L&0z
even when piles are installed in a group that is ‘‘rigidly’’ constrained by a stiff concrete pile cap. Assuming complete fixity during design oVfRp.a
~zero rotation at the pile head! can result in underestimated values of pile-head deflection, and incorrect estimates of the magnitude and 5g9K| -
the location of maximum bending moments. A simple and practical approach is presented for estimating the moment restraint that is !g~u'r'1
provided by the pile cap at the top of a pile group. The moment restraint, represented by the rotational restraint coefficient (KMu), serves Q 5 Mn=
as a boundary condition for analyzing groups of laterally loaded piles. Full-scale field tests performed on two pile groups with concrete #Wv8+&n
pile caps show that the proposed method for estimating rotational restraint provides results that are in good agreement with measured field Gh%dVP9B@P
performance.
