of glulam truss construction

and 5-ll8" x 7" webs and support a panelized roof overhead. The entire roof system was left exposed because of its pleasing visual appeal to visitors who will take guided tours through the winery.

which requires no welding or special inspection. The purlins and girders were spaced to accommodate the wood panelized roof system, which installs significantly faster than a steel deck over steel beams or open web steel trusses."

A DVOCATES for steel construcfa,tion like to say that steel has won the construction battle against wood in California commercial buildings. However, recent trends indicate glued laminated beams and trusses are staging an impressive comeback in light commercial construction.

In Plymouth, Ca., for example, architects and structural engineers specified exposed glued laminated beams for roof girders, purlins and roof trusses for the new 35,000-sq. ft. Montevina Winery. The wood system was selected for aesthetics, and because it resists the humidity and fermentation fumes which could corrode steel framing. Humidity is kept artificially high for winemaking purposes inside the winery.

The longest wood girders, spanning 48 feet, are 8-3/4" wide by 39" deep. The purlins span 33'and are 6-3/4" wide by 33" deep. The laminated wood trusses span 48 feet with 5-118" x 12" top and bottom chords

Carl Christofferson of Summit Engineering, Inc., the structural engineers, says that the glulam beam roof system was installed abolt207o faster than comparable steel framing. "Most connections used with the glued laminated beams are commercially available, requiring no custom design or fabrication, which results in significant savings in cost and lead time," he explains. "The roof's plywood diaphragm is nailed directly to the glued laminated purlins and girders,

STRUCTURAL engineers say the winery's wood roof installed about 20% fasler than a comparable steel system.

Subcontractor L. E. Boyd, Boyd Roof Structures, said the glued laminated trusses were assembled with hardware connections at QB Corp., Salmon, Id., and then taken apart for truck shipment to the job site. "Wood is the only material that would have permitted us to assemble the trusses at the plant and then put them back together at the site," Boyd notes. He said the ability to assemble, break down and re-assemble the trusses provided major cost savings because of truck transportation economies.

Near Fairfield, Ca., a new plastic bottle manufacturing plant started out as a 200,000-sq. ft. building and was redesigned nearly double that size, utilizing timber framing. It is the 360,000-sq. ft. Schmalbach Lubeca plant, with a panelized roof on parallel chord wood trusses that span 50 ft. between glued laminated roof girders up to 82 ft. long.

The architect and structural engineer said they selected all-wood roof construction for the building design rather than a steel girder and purlin system in order to simplify the details and speed up the schedule.

The roof system is set up with a bay spacing of 50' x 60', and has a clear height requirement of 35 ft. The glued laminated beams are 6-314" wide and vary in depth from 38" to 44". The roof purlins are open web wood trusses which span the 50 ft. dimension. The remainder of the panelized system is comprised of 2x6 wood joists spaced at 2.0' on center with l/2" plywood sheathing. The roofpitch is 1/4" per foot.

According to Tim McPartland, ATM Engineering, Sacramento, the fact that the roof structure was planned utilizing all wood construction enabled the redesign of the building from 200,000 to 360,000 sq. ft. in six calendar days. The design change was needed in order to accommodate the needs of Schmalbach-Lubeca. If the plan had been steel construction, the redesign could have caused a greater delay on the c.onstruction schedule.

"Steel purlins and girders require three to four weeks longer lead time in comparison to the relatively prompt delivery of glued laminated timbers," says McPartland, adding that timber framing requires less labor time for detailing than steel.

Project architect Jon Hamilton, Hamilton Van Niekerk Architects Inc., Rancho Cordova, Ca., says, "The open web wood trusses provided competitive cost, fast availability, and simple installation." He notes that it is easier to make adjustments at the job site with wood framing rather than rewelding joints on steel bar joist construction.

Craig Silva, project manager for L. E. Boyd Roof Structures, says the glulam roof framing also reduced costs because of the type of insulation that is used. Steel roofs usually require rigid insulation on top of the roof deck, while wood designs call for batt type insulation below the deck. "The construction time we saved with the timber system is important because every week you can save on a project this size makes a big difference," he adds. "The savings amounts to about 40 cents a square foot lower cost for wood systems compared to competitive materials. We like the simplicity of timber frame construction."

"Wood is the only material that permitted us to assemble the trusses at the plant and then put them back together at the site."