McCrossin Foundations, LLC (MFL) was contracted by Lane Construction Co. to complete various scopes of work for the I-70 Reconstruction Project at the I-79 South Junction in Washington, PA.
This contract included construction of 8-each drilled shafts for the support of two mainline bridge piers over an active Allegheny Valley Railroad track. The shafts consisted of 54-inch diameter soil sections with 42-inch diameter rock sockets. There were several challenges with these drilled shafts that complicated construction.
One of the biggest challenges was the variable depth to bedrock. The variance in the depth to rock in adjacent shafts was 10 feet, which posed a major challenge when planning the temporary casing needed in each shaft. There were also three different diameter reinforcing cages in the drilled shafts to further complicate matters. The tolerance on the top cage which embeds into the pier column was essentially zero. MFL decided to utilize a construction joint at the approval of the DOT in order to set this top cage “in the dry” to guarantee proper placement.