PACIFtC r MAIItSON LUMBER COITIPANY

7ll7 East Firestone Blvd. DOWNEY, C,olif. SPruce 3-2292 P.O. Box 243 TOpoz 1-6701

"SERVICE is our poromount stock-in-trode"

Steel cable drawn taut through the Iength of a wooden beam can add substantially to the beam's strength by a process called "prestressing," says the LI. S. Forest Products Laboratory.

Bending strength of glued laminated beams can be increased up to 30 percent by prestressing them with the steel cable, the lab reports. Varial'ility in strength hetween beams is reduced by nearly one-half, experiments reveal.

In practice this should mean, say the FPL engineers, that either smaller beams can be used in designing buildings {or specific roof or floor loadings, or load ratings of building can be proportionately increased when prestressed beams of a given size are used, other things being equal.

Some of the beams used in the research were made from common lumber with knots and other characteristics that impair strength. The lower quality beams actually were improved more greatly in strength than those made of higher quality material.

The steel cables are installed in special grooves cut beforehand in boards installed near one edge of the beam. When drawn taut against metal endplates, the cables tend to make the beam arch slightly. In construction, the beams are installed so that load bears against the arch, thus tcnding to flatten and deflect the beam in the opposite direction.

Wood ond the Polqris Missile

Vood is now being used to form the nose cone of the ner' Polaris missile which is fired Irom submarines and carries a nuclear explosive warhead.

This new use of man's oldest and most reliable building material resulted from research conducted by the Forest Products Laboratory at Madison, Wisc. Materials previously used for the nose cone-titanium and beryllium metals-frequently developed cracks and were much more expensive than wood, officials explained.

ALDER + JAPANESE BtRcH + DoMESTtc BtRcH + MAHocANy +

JAPANESE ASH + DOMESTIC ASH + PACIFIC MAPLE + EASTERN MAPLE +

BUTTERNUT + SOUTHERN OAK + CALIFORNIA OAK + JAPANESE OAK +

WALNUT + TENNESSEE CEDAR + LIMBA + YELLOW CEDAR + GUM +

SUGAR PINE + PONDEROSA PINE + CHERRY + BASSWooD + TEAK +

DOUGLAS FIR + PECAN + POPLAR + MAGNOLIA AND BRUCE

PREFINISHED PLYWOOD INCLUDING HARVEST PECAN + RUSTIC WALNUT +

WALNUT + PREMIUM WALNUT + MOUNTAIN OAK + FIRESIDE oAK +

RUSTIC OAK + PREMIUM oAK + BLONDE ASH + DRIFTWOOD ASH +

PREMIUM BIRCH + ANTIQUE BIRCH + RUSTIC BIRCH + AUTUMN BIRCH +

MOUNTAIN BIRCH + FRONTIER BIRCH + TWILIGHT BIRCH +

PROVINCIAL BIRCH + DRIFTWOOD MANILA + NATURAL MANILA +

BUTTERNUT + PREMIUM CHERRY + AMERICAN CHERRY + RUSTIC CHERRY +

COFFEE ELM + COVE + STOOL + STOP + BASE + SHOE + INSIDE CoRNER +

OUTSIDE CORNER + MATCHING STAIN + PUTTY STICKS + MoULDINGS +

CASINGS NOT TO MENTION oAK THRESHOLD + oAK DOoRSILL +

OAK NOSING + OAK STAIR TREADS + oAK RISERS + BLACKBOARDS +

BULLETIN BOARDS + HARDWOOD DOWELS AND CEDAR CLOSET LINING

ADD$ UP T(l 71 $EPARATE

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