Pumping contractor Cross Enterprises, Inc., Melvindale, MI, completed work on the largest silo in North America after 14 days of non-stop concrete construction. The new silo will house cement for one the nation’s largest building materials manufacturers, LaFarge North America. The structure is only one of several projects on the same site. The group of completed projects will eventually become LaFarge’s cement terminal, located along the Dertroit River in Delray, MI.

Under the supervision of general contractor Graycor, Inc., Homewood, IL, Cross placed an estimated 7,000 yards of 5,000 psi concrete during the monolithic effort. The contractor utilized a truck-mounted BPL 4000 pump to supply a 28-meter separate placing boom mounted on a zero elevation frame that rode the slip forms. The boom was fed through a hard line that ran up the side of the silo. Crews added sections of pipeline as construction moved upward.

Cross Vice President Frank Ferretti says Cross convinced project owners of the benefits of the Schwing equipment when contractors proposed the specs. “They were going to use a spider,” said Ferretti, “But when we took a look at the size of it, and the size of the interior and exterior walls, we decided that the combination of the pump and the boom was the most efficient way to go.”

As the largest silo in North America, the silo measures 183 feet in height and 104 feet in diameter. To support the giant structure, the walls of the silo measure 24 inches wide near the bottom of the silo, gradually decreasing to 12 inches near the top.

Cross manned the round the clock effort with three crew members on site at all times; one pump operator, one placing boom operator, and one relief operator. A total of six Cross operators swapped shifts during the 14-day period.

With ready-mix supplied by Koenig Fuel & Supply Co., Detroit, Graycor completed an estimated 12 inches each hour with the combination of the pump and the placing boom. Koenig hauled concrete from one Detroit-based batch plant for most of the project, and utilized a second when production called for quicker supply. LaFarge supplied the cement for the mix.

Koenig President Peter Fredericks estimated crews supplied 7,000 yards of concrete for the slip form application. “The hardest part of the whole ordeal was the 24-hour schedule,” he said.

Because slip forming is a deliberate and slow process, truck mixer dispatch consisted of simple radio communication between truck operators. “It was different each day, depending on where they were at. During box outs and column pours, production slowed and we were forced to wait it out. Typically, as one truck got close to nearing the end of a load, they’d either radio dispatch or the operator en route,” said Fredericks.

As a seasoned veteran of the pumping industry, Cross’s Frank Ferretti was impressed with the performance of the pump over the long process. “Twenty-four hours a day. Non-stop. That thing didn’t slip up once. We just turned it on and let it go.” The BPL 4000 is equipped with the Schwing patented Rock Valve, the concrete valve that has proven to increase uptime for pump owners throughout the industry. Partnered with the slow-start feature and 7-inch diameter cylinders, the pump lessens the impact on concrete and avoids pipeline shock. These features were particularly important as crews pumped through a vertical pipeline to reach the placing boom.

Schwing’s auto-greasing system was also vital to pump performance. With this optional system, all of the Rock Valve’s lubrication points are greased automatically, and grease timers are adjustable to ensure proper grease flow from each feeder. Owner Charlie Cross swears by the system: “I wouldn’t buy a pump without an auto-greaser. It’s peace of mind knowing the parts are greased – especially when you’re pumping for two straight weeks around the clock.”

As of February, portions of the silo, including sections of the roof, had yet to be completed. Contractors are currently bidding on the other projects within the new cement terminal. LaFarge North America provides a full line of construction materials including aggregate, asphalt, cement and cement related products as well as specialty products for erecting and finishing projects as well as material recycling and waste management. LaFarge North America is a division of LaFarge Group, providing materials in 75 countries.