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Building BonesWestern Archrib's added value glue-lam products form the structural backbone of many large-scale structures throughout Canada.By Tony Kryzanowski
These structural wood products, such as beams, trusses and archribs, are an important value-added wood product and are shipped to markets worldwide. For example, Western Archrib provided the structural beams for the sports centre built for the Nagano, Japan 1998 Winter Olympics. Its efforts have not gone unnoticed among peers in the wood manufacturing industry. Company chairman Jim Fargey was recent ly presented with the 1999 Paul Bunyan Award by the Canada Wood Council for his leadership in developing new sources and markets for glue laminated products.
Western Archrib has been in business since 1951 and started out filling the need for glue laminated beams in farm buildings and community centres in the postwar period. But even in those early years, the company was constantly looking for new marketing opportunities. That in turn led to the development of new products. By the mid1960s, they played a major role in the development of the potash industry in Western Canada, supplying the arches for large storage facilities. These buildings were typically 200 feet wide, with spans from 700 to 1,800 feet long.
"The reason that these big span arches were really suitable for potash storage is that wood is chemically inert, whereas steel corrodes badly with the salt," says Fargey. When potash mining development slowed in Western Canada, Western Archrib continued to supply the industry as it moved east and began developing in New Brunswick.
The company has also provided the structural arches for a massive terminal in Vancouver which stores potash prior to loading it on ocean freighters. The process of producing glue laminated wood products begins with the company's relationship with the sawmills that can supply raw material to their exacting standards. They purchase spruce and pine in dimensions from 2x4 to 2x12. Its moisture content must not exceed 15 per cent to ensure proper glue bonding, requiring sawmills to deviate from their normal practice of drying down to about 19 per cent moisture content. Uniform planing is absolutely crucial. Fargey says they pay a significant premium for the wood they purchase "but the mills have to get it right, or it doesn't work for us. We get a lot of cooperation from the mills, but it doesn't fit into every mill's program ."
Once the lumber arrives from the mills, it is placed in covered storage. As it rolls into production, it is warmed to room temperature and each board is subjected to a number of tests. The thickness of each board is measured and it is also tested for strength and moisture content. Each piece is then labeled according to those test results and conveyed to a sorting station. An employee manually sorts the lumber according to grade and weeds out those pieces that are rejected because of visual or strength defects. He will also pull those boards with moisture content over 15 per cent.
These are redried to specification and returned to the grading station at a later time. The manufacturing process actually begins in the office where technical staff produce a computer-generated schematic to match load requirements for a specific structural lumber order. When a schematic arrives at the lay up station, an employee will follow its directions like a road map and feed the exact combination of graded lumber onto a conveyor system that sends the lumber to a finger jointing machine, supplied by Industrial Woodworking in Texas. Over time, Western Archrib has doubled the capacity of its finger jointer feeding table and has become more automated wherever possible.
At present, the company has 80 employees. Fargey says they needed twice as many employees to manufacture the same amount of product prior to their move toward automation 20 years ago. The finger jointer saws a joint pattern on each end of individual boards, applies the glue, matches each board end to end and then conveys the finger jointed lumber to the radio frequency (RF) tunnel. Once in the tunnel, the glue line is heated to about 210 degrees Fahrenheit, causing each finger joint to cure in about 30 seconds. After the RF tunnel, board lengths encounter a chop saw so that each piece of finger jointed lumber is the exact length required. An employee then ensures that the correct number of board lengths are stacked one on top of the other prior to conveying each combination to the surface glue application station. Glue is applied to the face of each board length, and they are once again stacked one on top of the other. From this point, they will either be transported to the pressure clamping station, if no bending is required, or to the pressure clamping and bending station.
In order to bend the wood to achieve a particular design, Western Archrib first prepares a plywood template. A glued beam is placed on the template and, with the use of overhead cranes, the finger jointed boards are carefully bent to achieve the required shape. "At this point, nothing has bonded yet," says Fargey. "Instead of being clamped up straight, the beam is clamped up curved so that when the wet glue cures, it holds its shape. The clamping and bending has to happen within a certain window. You have about an hour of open time and, by that time, you should have your clamping complete ."
Clamped wood sits overnight. The next day, the beams pass through a planer to provide a finish suitable for most uses. However, all beams are then visually inspected and wood filler is applied if necessary. Recent improvements involve the installation of an inline sander. The curved beams are still hand planed. The final process is application of a sealer for water repellency and to help beams retain moisture in dry conditions. The finger joints and beams undergo a number of stress and bonding tests throughout the manufacturing process to meet CSA and international building standards. Given the growing range of engineered wood products and development of total structural wood systems, Fargey sees a bright future for glue laminated wood products. Their products are still in great demand with residential, commercial and institutional builders. However, Fargey has learned to live with the industry's ups and downs, as well as the fact that they will always be in competition with steel and concrete products. "Demand is cyclical," he says. "Church arches were popular in the 1960s and 1970s. They weren't so popular in the 1980s, and now they are back again. One of the pluses of wood, and laminated wood in particular, is the variety of architectural or aesthetic uses it can be put to by shaping it. We have that advantage over almost any other structural product ."
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