It’s widely reported that the Metropol Parasol in Seville, Spain is the world’s largest freestanding wooden structure. Some argue that the Daibutsu-den or Great Buddha Hall of the Todaiji Temple complex in the Nara, Japan is larger. Other worthy contenders are the LTA (lighter than air) craft hangars or airdocks, constructed at various US air bases during World War II.
Today seven of the original seventeen hangars remain at 4 US air bases (Moffett Field, Tustin, Tillamook and Lakehurst).
Built during a time of steel shortage, the airdocks are reputed to be the largest clear span timber structures ever built.
The two remaining airdocks at Moffat Field each comprise 51 Douglas fir timber trusses resting on concrete bases. The space each encloses is 340 m long by 115 m wide by 52 m high - a volume of more than more than 2 × 106 m3.
Structurally, the hangars feature an inverted catenary arch truss with a Pratt truss configuration. The cords comprise sawn boards joined by steel split-ring connectors and bolts. Fire-retardant salts were used to treat all timbers.
Surprisingly, after the prototype was completed, the remaining 17 hangars were finished within a year - which is testimony to the speed of building with wood.
