HIGH CAPACITY HOLLOW CORE BAR PILES

摘要

A 17 story building was constructed at the Brooklyn Navy Yard on a site with a long history of development.rnMost recently the site supported a dewatering well and craneway to service two adjacent drydocks. Thernsubsurface conditions generally consist of the following strata and approximate depths: miscellaneous fillrnand debris to 20 ft., organic soils to 35 ft., liquefiable sand to 45 ft., varved clay to 65 ft., glacial till to 95rnft. and gneiss bedrock.rnHollow core bar piles replaced 18 in. diameter caissons on a 1.67:1 basis. The resulting service loads onrnthe hollow bar piles were 600 kips compression, 21 kips lateral, 180 kips tension and 450 inch-kips moment.rnThe top 30 feet of the hollow bar was cased with a 16 in. x 0.375 in. Grade 50 steel pipe. The piles werernsocketed 6 feet into bedrock. An extensive load testing program confirmed the axial and lateral loadrncapacities. The paper will also discuss some adjustments to the installation procedure based on the load testrnprogram.