Shotcreting an Artificial Reef
Innovation and a Schwing stationary pump are creating artificial reef structures that will be placed along the Texas coast to provide marine life habitat. The Deepwater Horizon Oil Spill Resource Damage Assessment created after the BP spill in 2010 is providing the funds. The Texas Parks and Wildlife Department (TPWD) is the administrator for the project that will be the largest artificial reef ever placed in Texas waters. The 381-acre reef will be positioned six miles offshore from the Port O’Connor jetties and Matagorda Island in waters 10 miles or less from the Texas coast. Atlantis Marine Habitats LLC, Arcola, TX has been hired to construct a portion of the reef including manufacturing the reef components and placing them in the Gulf.
“We have done a lot of reefing business,” according to Wayne Bauer, Jr. co-owner of the company, ”Most of our work has been providing the barges and cranes to deploy the reef structures, but for this project we decided to manufacture the components for the first time.” Prior work utilized poured concrete components placed along the coast. “We designed a new structure with the help of Tom Hilton, who designed the pyramids that are eight-feet tall and 10-feet wide at the base.” The State of Texas originally ordered 2400 of the pyramids to be built and placed but recently added 500 more structures to the project.
“My original design for the pyramid utilized rebar tied together to form the desired shape, “ according to Hilton, “But the material blow through during shotcreting caused too much waste.” In order to sell the Texas authorities on the design, the company needed a viable way to manufacture it economically in volume. “We started with a plywood form in order to produce a finished product that the State approved, “ explains Bauer, “They wanted limestone placed into the wet shotcrete to provide marine life such as worms and other invertebrates with a hard substrate to burrow into.” Apparently local grouper will also burrow under a sunken reef, then turtles will enter the burrow and end up inside the pyramid. The forms have holes for the fish to swim through and a triangular hole to provide a means for sea turtles to escape.
After the State’s approval of the design, Atlantis Marine Habitats leased space near the coast and began large scale manufacturing with a batch plant, an SP 500 Schwing stationary pump and no experience in shotcreting. “We had a lot of help from Joseph Lowry from Six Brothers Concrete Pumping in Houston,” said Bauer. Six Brothers is a line pumping operation that does commercial and residential work in Houston and surrounding areas. “They contacted me and needed a concrete pump,” Six Brothers owner Lowry explained, “I told them to get a Schwing because production was critical and change out of a Rock Valve’s wear parts happens very quickly.” Six Brothers currently operates two new SP 1000 Schwing trailer-mounted concrete pumps. “I also encouraged them to get their operators ACPA certified,” Lowry adds, “All of my operators are certified as well as myself.”
In January of 2016 Atlantis Marine went into full-scale production with five welded steel forms. The batch plant produces a yard of shotcrete every seven minutes. “I had the pleasure of holding the shotcrete line and applying the mix to the forms, “ Bauer says, “And I quickly realized there had to be a better way.” The company designed turntables that would allow the form to be rotated at the push of a button and secured the shotcrete nozzle to a man basket supported by a forklift. The nozzle rotates with a set of handlebars. As the operator begins shotcreting from the bottom up, he rotates the turntable to apply 3-4 inches of material on the form and the forklift raises the basket until the form is covered. Plugs are inserted in the holes. “When we started, it took 21 working days to create 100 structures, then with the turntables we reduced it to 9 working days for 100 pieces and now we are able to produce 100 pieces in five working days,” according to Bauer.
The operation is set up in two temporary structures on the eight-acre site that is adjacent to the Gulf at Freeport. “There was a learning curve,” admits Bauer, “We discovered after a few plugs in the line that consistent grading of the 3/8-inch aggregate was critical to continuous production, so we began purchasing the stone from a supplier that would dedicate our deliveries to one driver who would make sure the truck was real clean before loading our rock.” The crew is shooting the structures through 2-inch line but plans to try 2.5-inch delivery hose. The company also modified the hopper of the pump by adding 10-inches to the sides. The mixing drum on the batch plant discharges directly into the pump for continuous operation. “With a half-yard of shotcrete in the enlarged hopper we discovered that by the time the shotcrete on the top worked its way into the valve it was a little too dry so the operator adds water during the charging process.”
The system has operated continuously for 14 hours per day during the beginning of the manufacturing process but now operates on 10 hour days. They have patented the design of the forms and are on schedule to complete the 2900 pieces and deploy them in the Gulf this year. “We were complete novices when we undertook this venture and have overcome lots of obstacles thanks to the folks at Schwing and advice from Joseph Lowry,” Bauer explains, “The pump has over a thousand hours on it and it hasn’t missed a beat.” The SP 500 is equipped with an 80 hp CAT diesel and has the capability to pump up to 45 cubic yards per hour and apply up to 1100 psi on the material. Its 20 gallon fuel tank allows it to run all day without a fill up.
“This will be the largest deployment of reef material in nearshore waters off Texas in the history of the Texas Artificial Reef Program,” said Dale Shively, director of the TPWD artificial reef program, “The project will provide much-needed habitat for all types of marine life as well as provide increased recreational fishing opportunities.” Bauer has invited Shaun Nelson, Schwing’s regional manager in Texas and Carl Walker, owner of Long Horn Line Pumps LP, Schwing’s distributor located in Fort Worth, to sign a pyramid at the ribbon cutting ceremony prior to the first piece of the artificial reef going overboard in 2017.
Owner: Texas Parks and Wildlife Department
Contractor: Atlantis Marine Habitats, LLC, Arcola, TX
Equipment: Schwing SP 500 stationary pump