Mabey Inc. prides itself on the strength and versatility of its equipment. When Everett, Pennsylvania-based Cottle’s Asphalt Maintenance Inc. was chosen to perform work on a Western Pennsylvania bridge recently, MBSI really put its claims to the test.
Cottle’s was chosen by the Pennsylvania Department of Transportation (PennDOT) to overhaul and replace the State Route 4003 bridge over Mill Run in Altoona. The heavily trafficked bridge had become worn due to years of use and nearly the entire structure, including the footers, required replacement. Traffic signal upgrades and pavement improvements leading up to the bridge would also be made as part of the $1.2 million project. To complicate matters, the small stream flowing beneath the bridge consisted primarily of storm runoff and was to be allowed to continue flowing during construction. Any significant obstruction to the bridge flow could result in overflow in the event of a flash flood according to PennDOT. Cottle’s needed a way to excavate at the site of the new footers, keep the Mill Run waters off of the wet concrete and still maintain water flow.
Owner, Mike Cottle turned to the Pittsburgh office of Baltimore-based Mabey Inc. to help conquer their challenge, and product specialist Scott Robinson found the right solution. Working closely with depot manager Rick Salatino, inside sales representative Jason Gorney and engineer James Reed, Scott was able to recommend Mabey’s 23′ interlocking sheets and JC struts to shore the ground above and around the new footers. “This was a total team effort,” said Robinson. “James, Jason and Rick did an amazing job. My hat’s off to the entire Pittsburgh team.” To complicate matters, nearby homes made driving sheets a concern. Even moderate vibrations from an excavator-mounted hammer could potentially damage any nearby foundations, particularly when driving the sheets into the hard Altoona soil. To help soften the ground and make sheet installation easier, Mabey’s excavator mounted drill (EMD) was brought in to stir and churn the soil and make it more receptive to driving sheets. Once the soil was sufficiently loosened, Cottle’s was able to use Mabey’s excavator mounted vibrator (EMV) to drive the interlocking sheets down into the dirt with only minimal disturbances to the adjacent structures.
The final arrangement consisted of two cofferdams, each roughly 34′ long and 15′ wide with JC struts running between them. The soil was excavated inside each cofferdam to a depth of about 16′ to allow for installation of the footers. Because each pit was self-contained, the stream was able to remain flowing between each of the cofferdam arrangements. Cottle’s’ Mill Run project is expected to conclude before the end of 2010, but it will stand as a testament to the ability of the contractor and the ingenuity of Mabey’s entire Pittsburgh team.