A.H. Beck installs drilled shafts under the foundation of a wooden bridge over Shoal Creek in Neosho, Montana.
The existing KCSRR Bridge (K172.4) is approximately 433ft long, 331 feet of which, is built on a timber trestle. The project included rebuilding the timber bridge with ballast deck concrete spans supported on drilled shafts. All drilled shafts were designed such that they can be installed outside of the timber bridge and caps can be installed under the wooden bridge. The new foundations consisted of drilling (20) 42” diameter cased drilled shafts with 36” diameter rock sockets and (3) 24” diameter shafts with 18” rock sockets. Each shaft was drilled to a depth of roughly 30 feet, with 10 feet being rock socket. The unconfined compressive rock strength being drilled ranged from 6,000-15,000psi. A. H. Beck drilled out the rock sockets using rock augers, core barrels, roller barrels and a European style, track mounted drill rig.
