FREDERICKTOWN — Located within the heart of downtown St. Louis is Tucker Boulevard.
Unknown to most who travel this roadway, beneath it lies a massive tunnel that was constructed in 1931 and 1932 by the Illinois Terminal Railroad. It starts at the St. Louis Post-Dispatch near Washington Avenue and goes to Cass Avenue.
The original purpose of the tunnel was to alleviate traffic congestion between automobiles and streetcars and to transport commercial goods and materials. According to the St. Louis Post-Dispatch, the trains stopped running in 1958.
Over time the tunnel was used less and less for transportation and eventually became a passageway for utility transmissions. In the last years of its life, it was used as shelter for homeless people.
"Time has taken its toll on the tunnel," said Patrick Rosener, one of the owners of a Fredericktown Company called Versa-Tech Inc. "The walls that support the tunnel have become unstable and threaten the stability of the tunnel, the roadway above and those multistory buildings lining its street level route."
He said the engineering solution was to fill the tunnel.
Commonly referred to as geotechnical fill, this sort of ground stabilization is typically achieved with dirt, rock or lightweight concrete.
He said detailed calculations revealed that filling the tunnel with these sorts of heavy materials, (usually 125-200 pounds per cubic foot) would create lateral pressure sufficient enough to push the original tunnel walls outward and actually accelerate its collapse.
"The solution was to find a material strong enough to support a roadway and yet light enough so as not to create outward pressure on the walls," he said.
He said engineers decided to use 1.5 to 2 pounds per cubic foot of expanded polystyrene foam blocks to fill the tunnel.
The project attracted competition from every major manufacturer of this foam, but the Fredericktown company was fortunate enough to win the bid for material supply.
The first phase of this project is underway and is slated to use more than 3,300 blocks totaling 675,000 cubic feet of foam.
"We are extremely proud that our small company has been viewed as the best choice nationwide for this project," Rosener said. "Our campus is now home to an outside inventory of nearly 2,400 blocks and counting. The storage consumes several acres."
The 2,400 blocks on hand are being stored both inside and outside. They are going to wait until the project starts before they produce the last 1,000 or so.
There are plans to build a new four-lane road on top of the tunnel that will eventually connect with a new Mississippi River bridge north of downtown.
Versa-Tech Inc. has been around for 10 years. It was formed in March of 2000 as a partnership between Jeff Geile, John Moorman and Rosener.
"All three owners remain full-time employees and are active in all aspects of the daily operations," Rosener said.
It started in a small empty building on Sargent Drive and has expanded in the location several times. The manufacturing facility is 65,000 square feet. It's outfitted with the latest in molding, curing, fabrication and packaging equipment.
It normally employs 35 to 40 people.
Rosener said expanded polystyrene geofoam is becoming common as a long-term, cost effective solution for roadway stabilization, embankment construction, foundation settlement challenges. The foam has been used in highways and airport runways for about 20 years.
It is used as insulation for roofs and refrigerated grocery cases, or as floating concrete barges.
They also make shipping coolers for Dippin' Dots Ice Cream. Their products are used in floral arrangements and in boat seats for buoyancy.
The manufacturing process starts with small pellets of plastic that look like sugar. The petroleum-derived raw resin is purchased from all over the world, depending on the commodity market.
The resin often comes in 2,500 pound bags. After going through the manufacturing process, the tiny beads increase 45 times their original size.
The first step is softening the beads by exposing them to steam and pressure so they are filled with more air than plastic. Next they are placed in a dryer.
From there the material is stabilized and staged for molding. After that the material is introduced to even more steam and pressure which causes the beads to fuse together.
The foam comes out in large blocks almost as tall as the ceiling.
The blocks come in a range of densities, with some of these large blocks weighing in excess of 300 pounds. The foam can be cut into various shapes and sizes.
Versa-Tech is a big recycler of the product. Scrap products go into a machine where they are remodeled and compacted for recycling.
"We don't throw anything away," Rosener said. "Nothing goes to the landfill."