Harper's Ferry Bridge Project
WV DOH Project S319-340-14.65 00

Development of innovative technique to excavate 12'6" rock sockets for bridge caissons utilizing large diameter air rotary drilling techniques.

Corman Construction Corporation
12001 Guilford Road
Annapolis Junction, MD 20701

This project called for the excavation of seven 12'6" diameter shafts through bedrock to support the new Route 32 bridge over the Shenandoah River. The caisson shafts were required to be excavated within the river channel, and on each embankment. The requirement for excavation within the channel itself placed strict restrictions on the methods of excavation that would be allowed, due to environmental concerns. The design of the caissons themselves prevented the use of blasting or mass excavation techniques to remove the rock. In addition the General Contractor had established an aggressive schedule to complete the project which would require double shifts and night work.

COOK developed an excavation method that addressed the environmental, engineering/design and schedule concerns simultaneously. The versatility and speed of this method allowed COOK to meet the project schedule even when differing site conditions where encountered which required the Owner to redesign one of the caissons.