World's biggest woodpile

'fHE WORLD'S largest all-wood . l. structure. a.giant platform destineil for test use in simulating the effects of a nuclear detonation, is nearing the half-way mark at Kirtland Air Force Base, near Albuquerque, N.M.

Even the bolts and nuts are wood.

Scheduled for 1980 completion, Trestle Project, as it has been officially designated, will utilize 6.5 million board feet of glue laminated lumber, pressure treated to resist decay. Laid end to end, the timbers would reach 1136 miles farther than from Los Angeles to Vancouver.

The gargantuan structure, I 2 stories high, is engineered to support tlte 275ton weight of America's largest airplanes under stresses of up to 100 mph winds. Fractional tolerances are believed more exacting than any heretofore known to the wood fabricating field.

Wood was critical to basic preliminary planning of Air Force Weapons Laboratory experts because of its nonconductive qualities.

Test planes are to be bombarded with electromagnetic impulses of a megavolt intensity, to perfect pro- tection against inrpairment or destruction of sensitive electronic instruments such as might be carried aboard airborne command posts. equipment essential to national survival in the event of atomic attack.

Use of wood makes it possible for the test plane to appear electromagnetically as if it were in actual l1ight. To transfer shear loads, design engineers have specified use of metal split rings, so small they pose no problem in electromagnetic conductivity.

The glulams are being supplied bY Standard Structures, Santa Rosa, Ca. The order involves more than 410,000 individual pieces of lumber, forming 15,000 laminated timbers engineered to meet exacting tolerances established by the Air F-orce.

Rigid quality control dictates that edge gap tolerances not exceed l/4" for the entire length of 37-112" x 15" x 52' deck planks, composed of fouredge laminations. Other beams include l5-7 18" x 52-l12" x 126'girder members and 12" x 12" x I l1' columns.

Prior to lamination the wood segments are being pressure treated by McCormick & Baxter Creosoting Co.,

San Francisco, Ca., using the "Cellon" process as a safeguard against decay and insect attack. Cellon is a registered trademark of KopPers ComPanY, lnc., Pittsburgh, for which McCormick & Baxter is a licensee.

Bolts, nuts and gusset plates for the towering trestle, sited in a shallow basin scooped from the desert floor, are made of laminated beechwood, esPecially imported from EuroPe, and formed, under intense pressure, with phenolic resin, by Permali, Inc., Mount Pleasant, Pa.

Approximately 100 different lengths of threaded fasteners, ranging from a minimum of 12" to a maximum of 77", will be required for the structure.

Overall size of the trestle will be 1,345' long by 200' wide bY 125' high. The laminated timbers are being drilled at the site, with individual sections, fabricated on a mobile platform, being lifted by three cranes into final position atop concrete footings.

Story at a Glance

World's largest all-wood structure, 12 stories high, will use 6.5 million board feet of lumber use is for a test simulating effects of nuclear blast.