Democrats say President Trump's wall would either be too costly, too laborious, or too complex to complete. And yet, America is now living in the age where Marines at Camp Pendleton can successfully 3D-print a reinforced concrete bridge in just 14 separate hours.
According to Fox News, in December of last year, U.S. Marines assembled the first ever 3D-printed bridge on site in the Western hemisphere. Typically, such bridges are printed in a factory. A Marines spokeswoman told Fox News that construction took 14 separate hours over 3 days with breaks and sleep in between rather than 14 continuous hours.
"They didn't run the printer for 14 continuous hours," she explained. "So it took about 3 days, working for 8 hours per day, and going home at night."
Once the printing had finished, the bridge was left to "settle" for 36 hours before it could be assembled, which the spokeswoman said "took less than 4 hours." Fox News further described the construction process:
The footbridge was printed as part of the Corps’ annual Steel Knight exercise. Marines were trained to use the Automated Construction of Expeditionary Structures (ACES) 3D-printer.
Members of the 1st Marine Logistics Group worked on the project with the Marine Corps System Command Advanced Manufacturing Operations Cell and the Army Corps of Engineers.
Marines were also helped in the construction effort by sailors from Naval Mobile Construction Battalion 5 at Port Hueneme, Calif. The Seabees brought a volumetric mixer to the Camp Pendleton site, saving about six Marines from mixing large amounts of concrete.
In a statement, Capt. Matthew Friedell, AMOC project officer, said the project had two goals: teach Marines to operate equipment on their own and to lower the number of hands necessary for completion.
"One of our goals was for Marines to learn to operate the equipment on their own, which they did and it was great," said Capt. Friedell. "Another goal is that each time we do one of these tests, we use [fewer] people. Ultimately, we want one person standing there who hits ‘print,’ and the machine does all the work. We’re getting there."
"This shows how close 1st MLG and the Marine Corps are to the bleeding edge of innovation," he continued. "We didn’t seek to break any new ground, but with Marine ingenuity, we sure did."
A previous job in August 2018 had the Marines conduct a barracks hut print, which Friedell said was more difficult due to the concrete-mixing.
"The barracks hut print was more difficult because Marines had to mix the concrete [themselves]," Friedell said. "They had to take five-gallon buckets of gravel, pour them into a bigger bucket, and then use a fork lift to lift them up into the big mixer. The mixer had to mix it and then dump it into the pump. For [the bridge project], we used the volumetric mixer, which did all the gravel, mixed all the concrete and got it ready to pump without anyone doing the really hard work."
The project was a 3D-print for a 500-square-foot barracks. Marines completed the work in just 40 hours.
The bridge is just the latest example of 3D-printing innovation by the Marine Corps. Last year, for example, Marines used a specialized 3D concrete printer to print a 500-square-foot barracks room in just 40 hours.