The new outdoor infantry immersion trainer (O-IIT) at Camp Lejeune in North Carolina is a 5-acre complex of 51 buildings with 129 rooms, located next to the Mobile Military Operations on Urbanized Terrain training complex. The O-IIT is used to immerse marines in the sights, sounds, odors, and physical environments of urban battlefields.
At Camp Lejeune, which already had an indoor infantry immersion trainer, the new O-IIT will provide soldiers with a level of realistic training on par with the training offered at Camp Pendleton in California. Marine units will be able to work with the infantry immersion trainer support center to craft training scenarios geared toward the needs of their planned deployments or future missions.
To add realism to training, the O-IIT’s village setting features a sound system, a centrally controlled LED lighting system, and an odor-generation system that can simulate the smell of gunpowder or odors one might encounter in open-air markets. No live fire is used, but units use blank ammunition. The decision-making environment includes urban structures designed to replicate geographic locations; in addition, virtual simulation and video instrumentation are used. At the end of each training session, the units are given a DVD of after-action reviews for further study.
The mock village includes precast concrete structures and modified shipping containers, courtyard walls, a modular after-action review building, and storage containers. Given the widespread use of concrete as a building material around the world, it made sense for precast concrete to be specified. Also, precast concrete can endure the rigors of marine training, as well as the coastal environment of Camp Lejeune, and the inherent durability of precast concrete allows for future modifications and reconfigurations at the training site.
A variety of forms, colors, and faux appurtenances were used during manufacturing to create a geospecific appearance for the precast concrete structures. The one and two-story buildings are designed to withstand all loads, as well as rotor wash, fast roping, and other training techniques. The labyrinth of buildings replicates an authentic North African village. Eschewing their typical building code criteria, the design team incorporated nonstandard stairs, doors, and window openings.
Architect Roy Selvidge, AIA, principal of LS3P, says the layout is more organic than rectilinear to challenge marines as they move through the buildings. “The rooms are different sizes, and you don’t really have a clear view through them,” says Selvidge.
Precast concrete satisfied all the requirements of the U.S. Marine Corps for the O-IIT. To obtain military funding, the project team had to ensure that the buildings would be relocatable. “Precasting the concrete into transportable sizes and shapes that allowed for future relocation was the only feasible solution,” says Joshua Schmitt, project manager for GATE Precast Company . “It was necessary to disassemble the buildings, transport them, and reassemble them, using integral footings and bolted connections to ensure their functionality,” he adds. “By using a minimal amount of welding, the connections could be removed and returned to their original locations with no additional welding needed in the future.” Continuous corbels were cast on the front and rear faces of the panels to support the second story and roof slabs. Many of the precast concrete panels included a large number of openings, which required post-tensioning. Strongbacks were used liberally throughout the job.
Most panels were shipped on their side edges, but about 20% of the panels had to be shipped flat, which posed an extra challenge because of an integrated footer. The precast concrete producer developed an innovative series of “teeter-totters” to allow the panels to absorb the twisting of the trailer. For panels transported on their side, the footer helped balance the panels and also served as a convenient location for running out the live ends of post-tensioning strands, where needed.
Even though the O-IIT’s village looks like a war zone, the precast concrete buildings required high-quality workmanship. Various production techniques were used to create the mock village. The buildings were designed to appear damaged, and some had holes in the walls to replicate explosion-related damage, which added to the realism.
While there was some replication in the building components, many of the pieces were unique. A large variety of colors were used and the formliners were often nonlinear, so coordination was required to ensure that the patterns and colors correctly lined up from one panel to the next. The precast concrete producer and the architect worked together to determine different levels of roughness and texture for use throughout the village.