Understanding soil conditions can make or break proper press pit and foundation construction
Above: A geotechnical report is the first to-do item on a checklist for building a press pit that can properly support a large tonnage press like this 3,000 ton machine.
Understanding soil conditions can make or break proper press pit and foundation construction
October 2015 - The Cambridge Dictionary of American English defines the idiom “out of sight, out of mind” as not able to be seen so not thought about. If you dig deeper the reference states, “problems in remote places can be out of sight.” It’s an astute observation that could explain why some manufacturers purchasing a large stamping press tend to skip the all-important geotechnical report—a crucial step on the checklist for proper press pit and foundation construction.
“People look at the surface of the ground and think it’s fine,” says Tom Lytle, vice-president of Delta Industrial. Headquartered in Chesterfield, Michigan, Delta Industrial is a foundation contractor for most major machine and press manufacturers. “But there are a lot of variables to consider when you are talking about a press that can weigh several thousand tons.”
Collapsible soil, saturated sand or loose stone may lurk just below surface. Evaluating soil stability, the presence or absence of ground water and whether an existing subgrade has to be modified can impact foundation construction costs.
“It would be very unfortunate to skip the soil analysis, get your press up and running and then find out you have a ground problem,” says Lytle. “At that point, the foundation would have to be reworked or removed. Loss of production hours and additional rigging costs are just for starters. A foundation project for a larger press can start at $100,000. A large press line with a bolster, feed-line, stacking equipment and scrap conveyor can exceed $1 million in foundation work. When you weigh that against a geotechnical report that typically costs anywhere from $3,000 to $5,000, it’s an excellent value—the best money a company will spend.”
Changing of the guard
The temptation to skip steps is due in part to the way companies are doing business these days, says Lytle. “We used to work directly with owners, plant managers and floor managers,” he says. “Over the last five to 10 years this role has been turned over to purchasing agents. These individuals can effectively crunch numbers for a project but they don’t generally have a lot of equipment or shop floor knowledge. We work to educate them about foundation design and the myriad details involved with a press installation.”
With a geotechnical report, Delta Industrial can evaluate press load and soil bearing, compare the data to press tonnage and determine “what needs to happen with the foundation based on existing soil conditions,” explains Lytle. “We can make assumptions without the report. In that type of situation we dig to depth but we still have to have a third party perform a soil bearing study to determine capacity at depth.”
In addition to a geotechnical report, press type, process application and the machine’s sensitivity to existing plant operations top the checklist. Potential removal of a company’s concrete floor, the type of equipment needed for construction, the best excavation method for a deep foundation, construction routes in and out of the facility, housekeeping and dust control, potential interference with existing building column footings and utilities and the addition of processing equipment like scrap handling and material storage are also part of the equation.
“It’s like a puzzle,” says Lytle. “If you don’t consider all the pieces the press will never perform correctly.”
Delta Industrial has plenty of experience solving puzzles. Providing pits and foundations for stampers comprises nearly 50 percent of its business. Lytle estimates total sales for the company at $30 million.
“Market growth in the stamping arena has remained very consistent,” he notes. “Our first quarter 2016 workload is strong. Fourth quarter, which can sometimes slow a bit due to year-end budgets, has also been strong. The automotive market dictates a large part of our stamping pit and foundation work but we also do a good bit of business in the aerospace and medical arenas.”
Lytle adds the company has also attracted a number of new prospects. “Customers are finally starting to make a profit, which isn’t a dirty word,” he says. “People are regaining their footing and are able to make better decisions moving forward.”
Ford Motor Co. has been a major contributor with its consumption of aluminum for body components and structural parts. The push has a number of facilities making equipment adjustments to add stamped aluminum to their product offerings.
Tech tightens tolerances
Using aluminum requires specialized material handling, scrap removal and raw material storage.
“The stamping environment has to be very clean,” explains Lytle. “The right scrap removal method is also critical. Aluminum is a high-dollar material so you want to make sure you are recouping every dollar from your scrap. We’ve developed underground scrap removal systems that allow the operator to switch out components if they decide to run aluminum. This allows them to ensure their scrap remains pure.”
Hot stamping continues to be a high activity area for Delta Industrial. The process forms metal heated in excess of 900 degrees Celsius then quenches the material in the die to create high-strength steel. Forming high-strength steel can affect foundation requirements, as can the newer smart machines, which may need to be isolated from other equipment and forklift traffic.
While the press, production and process may be different for each application, Lytle says Delta Industrial’s checklist remains relatively unchanged.
“We want to determine maximum efficiency of press operation and space so operators don’t have to move material more than once,” Lytle says.
Delta Industrial is also integrating technology into its own operations to achieve tighter tolerances and gain efficiency. “We rely a great deal on technology,” Lytle says. “We use AutoCAD to develop construction drawings from excavation to assembly and steel detailing. We can provide customers with a complete drawing package.”
Advanced surveying equipment has replaced tape measures and string line. “We used to pull measurements off a building column with a tape measure, mark the floor and put up a string line,” Lytle says. “The evolution of technology has allowed us to achieve tighter tolerances.”
Delta Industrial has also put the power of the tablet into the hands of its foremen. “We have projects all over the country,” Lytle says. “If I have a foreman in Texas for example, he can transmit safety information, equipment inspection details and checklist data to our office and communicate with us in real time. We have 20 foremen but the boost in their accuracy and efficiency outweighs the cost of the tablets.”
In today’s cost-driven business environment, Lytle says understanding how construction processes will impact plant flow and production should be the first consideration when a company is planning a large equipment purchase. FFJ
