Problem: The box beam above the hangar doors was experiencing degradation and decay. Sagging resulted causing the doors below not to open. Continued decay would lead to structural instability of the box beam and eventual failure.
Solution: An innovative inverted bowstring truss with a post-tensioned bottom chord built in-place, was designed and constructed. Incorporating post-tensioned technology used in major bridge structures, the truss design actually provided lift of the box beam and a net tension upward to counteract initial sagging.
Stressing the post-tension cables with 500,000 lbs. of force!
The Tillamook Blimp Hangar was built at a time when nonrigid airships had a vital role providing protection from enemy submarines. Today, this massive facility is certified in the Guinness Book of World Records as the largest wooden building in the world, standing 21 stories high.
Kramer Gehlen & Associates
400 Columbia St, Suite 240 • Vancouver, WA 98660-3413