H-Bearing Piles in Limestone and Clay Shales

A pile test program was used to finalize the foundation design for railroad bridge piers founded on H-bearing piles driven through alluvial and glaciofluvial deposits in bedrock of the Pennsylvania system. Twenty-four test piles were driven for length determination and 14 piles were extracted to check for damage while driving. The design bearing capacity was verified with 10 static load tests. Adequate bearing could be obtained for a design pile load of 50 tons by either founding on a thin hard limestone stratum or driving into about 10 ft of shale. The pile capacity was not significantly altered by remolding of the shale or breakup of the limestone strata. The pile extraction program showed piles were damaged if driven through limestone strata.