Cross Concrete Pumping, operating from their Melvindale, MI plant, is a year and three months into a two-year contract on a retention basin project commissioned by Oakland County, MI. The George W. Kuhn Drain project will require a total of 108,000 cubic yards of pumped concrete, including one giant 4-foot thick mat, 600 20-foot high columns, walls, and decks.

Three of Cross’ long boom pumps have been on the project since the beginning, and have completed over 20 large base mat pours, several large deck pours and the accompanying walls and columns. Ready-mix supplier Michigan Foundation Company (MFC), with locations in Detroit, Trenton and the Wayne/Canton area, has provided air-entrained concrete throughout construction. MFC’s Vice President of Operations John Formentin estimates the project was nearly 80 percent complete in late October.

The Construction Management team from Walbridge Aldinger Company, headquartered in Detroit, has been overseeing work on the drain site since September of 2001.

Contractors’ efforts include the widening of the existing underground basin, which measures 60 feet wide by 20 feet high by two miles long. Before work commenced, the retention basin held a total 60 million gallons of rainwater for eventual processing in the county sewage system. Walbridge Aldinger, with the help of Cross and ready-mix supplier Michigan Foundation Company, Detroit, has invested several years in a project to widen a 1200-foot span of the existing structure. In the end, a total 108,000 cubic yards of concrete and 13,000 tons of reinforced steel will widen the span by a total 250 feet. Walbridge Project Manager Brian Pass says this expansion will increase the basin’s capacity by 30 million gallons.

Once construction on the expansion is completed, the entire basin will be covered with dirt and serve as a holding tank for the excess rainwater. As the treatment plant can handle the volume, the rainwater will be released from the basin into the disposal.

MFC’s John Formentin commented on the bulk of the project. “This is a huge concrete project,” he said, “The capacity of this thing is absolutely enormous. It feels like we’ve been on this job forever, and we’ll still be supplying through the winter.”

For one year and three months, Cross has utilized the same three pumps for the basin’s concrete projects; the contractor’s S 58 SX and two 55-meter boom pumps have been called to the site since the beginning. Approximately once every three weeks, Cross operators set up around the open-cut excavation at 7:00 am. To complete a typical 2500 to 3500-yard large base mat pour, pump operators clock in a seven-hour day. The KVM 55s are custom carrier mounted concrete pumps with overhead Roll & Fold® 4-section placing booms and provide horizontal reach of 151 feet, generous enough for pump set up virtually anywhere on the site. The S 58 SX boom pump, which boasts Schwing’s second-longest boom, provides a reach of 162 feet. The pump’s Super-X outriggers provided a compact 29’-2” set up in and around the drain excavation. With the tight job site and specs changing daily, the long boom’s small footprint was essential. Cross’ maintenance supervisor reports that the pumps receive normal maintenance and are always up and running for on-call duty when the project calls.

Contractors have been working in segments to complete concrete construction. The long booms complete work on portions of the mat, followed by the 20-foot wall forms, which are reinforced with steel. Work on the structure’s columns follow completion of the walls. The decks of the basin are then constructed, measuring in at between 700 and 900 yards per pour.

To supply pumps for the larger base mat pours, MFC commissions 24 of their 85-truck fleet to haul ready-mix from one portable batch plant on site and their Detroit plant, an estimated 30-minute one-way commute. Lane closures and minor traffic re-routing has allowed easy access to the job site.

MFC has had to carefully control the quality of the ready-mix, which consists of 4000 psi air-entrained Type 1 cement with GGBFS mix. “We have a very proactive quality control department,” said Formentin. “We have NRMCA certified concrete plants. We have testing facilities we use to make sure the concrete performs. We’ve been working hard to ensure we use only top-quality products and procedures to provide this mix.” The manufacturer’s patented Rock Valve handled the tough mix with no problems.

According to Brian Pass, Project Manager for general contractor Walbridge, soil retention for the walls of the excavation proveed to be no problem. Pass estimate that the area’s earth caries strength of around 9000 psf, and has required very minimal earth retention.

Walbridge and several subcontractors are also progressing on new screening and treatment facilities to ensure the environmental soundness of the expansion. The drain should be fully operation in late 2005.