Experience with Deep Foundations in the Philadelphia Metropolitan Area-PPT Presentation

PPT Presentation

Pdf Summary

The presentation reviews deep-foundation experience across approximately 30 projects in the Philadelphia metropolitan area, focusing on six examples. Local conditions include Wissahickon Schist bedrock, karst along I-476, variable soil deposits, high groundwater, and potential soil corrosion and contamination.<br /><br />Foundation solutions varied with site conditions. Projects used spread footings, steel H-piles, concrete-filled pipe or monotube piles, and drilled shafts with rock sockets. At Philadelphia International Airport, friction piles were selected instead of extending foundations through a deep drinking-water aquifer to bedrock. At Mustin Field, wick drains and surcharge preloading helped accelerate settlement, with piezometers and settlement plates used to monitor performance.<br /><br />Construction challenges included railway coordination and limited access, high water tables, unexpected existing foundations, and traffic and weather constraints during investigations. Other projects required adjustments for corrosion-related pile section loss, uplift and downdrag, lateral soil movement, contaminated soils, and the need to match existing bridge foundations.<br /><br />Overall, foundation design depended on the consistency of overburden soils, bedrock depth and competence, groundwater and aquifer constraints, and environmental conditions. Spread footings and predominantly end-bearing H-piles were common, while friction piles were appropriate where deep bedrock or aquifer protection made end-bearing solutions unsuitable.

Keywords

deep foundations

Philadelphia

Wissahickon Schist

karst

groundwater

H-piles

drilled shafts

settlement monitoring

corrosion

pile foundations