Tustin Hangar 1 | USA
Images of the project
Tustin Hangar I
In early October 2013, Tustin Hangar 1 at the former Marine Corps Air Station (MCAS) experienced a partial roof collapse. Constructed in 1943, the hangar housed blimps that were used for Pacific Coast reconnaissance during World War II. At 300 ft wide at the base, 1060 ft long, and 178 ft tall at its peak, it is a massive structure.
The Historical Structure
Due to a shortage of available steel at the time of construction, it was built primarily of wood. The roof is supported by 51 reverse-catenary arched trusses spaced at 20 ft on the center, with multi-ply dimensional lumber chords and webs, ranging in size from 3×8 to 4×16. Hangar 1, along with its sister, Hangar 2, is distinguished as being the “Largest Wood Frame Structures in the World.”
During the partial roof collapse, the top four panels of the three northern-most roof trusses fell to the floor, creating an approximately 50 ft wide by 70 ft long hole in the roof and leaving the remaining portions of those three trusses cantilevered from their bases on each side.
Roof Stabilization & Monitoring
To contain the effects of the collapse, an innovative stabilization system was constructed, consisting of steel cables anchored to the affected trusses that were vertically supported by 190-ft tall steel towers placed on each side of the hangar.
Sixense was hired to design and implement a reactive monitoring program capable of tracking the displacement behavior of the remaining structure and providing early warning of any potential impending failure. AMT Cyclops and Tiltmeters were deployed, in conjunction with our web-based platform, Geoscope. This platform allowed the parties involved to see the data in near-real-time to follow the stabilization, while the trusses with missing crown portions were slowly pulled back up toward their pre-collapse location by the action of the tension in the steel cables.
Sixense’s Role at Tustin Hangar 1 Today
Our tiltmeter system has remained in place after the structure’s stabilization and it continues to collect data at 1-minute intervals. As an additonal safety measure, the system gives real-time warnings should any significant movement occur.