pile groups

negative skin

load tests

laterally loaded

concrete piles

shaft resistance

pile installation

vertical load

p-y curves

uplift capacity

A program of research on laterally loaded piles for offshore structure has included field test with an instrument pile, laboratory model testing, and development of correlation for design. The work has been sponsored by a group of five oil companies. Three loading condition are considered to be particularly pertinent to the design of laterally loaded pile in soft normally consolidated marine clay. These are (1) short time static loading, (2) cyclic loading such as would occur during the progressive build-up of the storm, and (3) subsequent reloading with forces less than previously maximums. Good general agreement exist between conventional static-loading ultimate-resistance concept and experimental results, provide due allowances are made for the reduced vertical restraint at shallow depth, where it is insufficient to cofine plastic flow to horizontal planes. Force-deformation characteristic based on approximate theory produce satisfactory agreement between computed and experimental behavior of the pile-soil system. The mechanism of cyclic loading characteristic are qualitatively illustrated by typical results from laboratory model studies. Deterioration in resistance because of cyclic loading is most severe at shallow depth and with large lateral deflection of the pile. A correlation based primarily on result with the instrumented pile tested at Sabine, Texas, gives satisfactory prediction of pile deflection and moment over a wide range of loading condition. Estimates of response for reloading after cycling at a higher load made by considering that most of the lateral soil resistance is estimated for deflection smaller than those previous attained. The correlation are summarized and recommendation given for their use in design. Introduction The ability to make reasonable estimates of the behavior of laterally loaded piles is an important consideration in the design and construction of many offshore installations. This is particularly true in the Gulf of Mexico where large lateral forces are produced by winds an...

Correlation for Design of Laterally Loaded Piles in Soft Clay