One Theater Novelty Not Even Shakespeare Knew-G1ued Lraminated Roof Arches

Striking and beautiful examples of a new and growing industry in the building field-the built-up wood arch industry-are the glued laminated Douglas fir arches which support the auditorium roof of the new Penthouse Theater now being brought to completion on the southwest corner of the University of Washington campus, Seattle.

The theater is an unusual project in many respectsadding as it does both novelty and charm to a campus already world-famed for its architectural distinction-but, in the words of the University of Washington Daily, it is "the roof truss construction in the new theater which is attracting wide attention from builders and designers all over America."

Rising vertically twenty feet, the roof supports are anchored on the outer rim of the auditorium. They converge in a "hub" at the peak of the structure, supporting the roof over an octagonally designed auditorium without the use of center supports and thus eliminating "behind the pillar" seats common to the ordinary theater. When complete, the auditorium will seat an audience of. 20O persons on circular tiers of seats around a center stage, in the classic Greek manner. It will be opened to the public May 16, 1940.

The arches were designed by Sergius Sergev, associate professor of Civil Engineering of the University; and the project was under the supervision of Charles C. May, superintendent of buildings and grounds, and his assistant, C. K. Weidner.

It is of particular interest to note, too, that the eight laminated supporting arches were fabricated by WPA workers on the project under the supervision of the University. Charles North was senior project supervisor for the WPA.

Port Orford Cedar

(Also known as White Cedcr or L<rwaon Cyprees)

Crossing Plcmls

Decking

Tunnel Timbers

The arches are made of Douglas fir boards, nine-sixteenths of an inch thick and five and one-half inches wide. These boards are of random lengths and scarf-spliced with glue to form a piece long enough to extend from the heel to the crown. The arch curve in each case was made by bending the laminations in a clamping jig which also supplied the pressure.

Although this type of construction has been used with success in Europe for more than thirty years-even such structures as vehicular bridges and railroad sheds being built with laminated trusses-it rvas the construction of an experimental service building for the U. S. Forest Products Laboratory, at Madison, Wisconsin in 1935, which marked the real beginning of the present increasing use of the built-up wooden arch in this country, according to T. R. C. Wilson, senior engineer of the Laboratory.

Since then-Mr. Wilson points out in Technical Bulletin No. 691, called "The Glued Laminated Wooden Arch" and just published by the U. S. Forest Service-around 1@ buildings or halls of the same general type have been built in midwestern states, including churches, community halls, gymnasiums, g'arages, dance halls, and Gothicstyled dairy barns. The arches in these buildings vary widely in shape but not in design principle.

Don G. Abel, Washington State WpA Administrator, in telling newspaper men about the new Penthouse Theater on the University of Washington campus, said: .,shipbuilders are already showing interest in the new trusses tor possible use in manufacturing wooden ships' ribs.',