Glued laminated timber
The partnership for this project lead to the creation of Unit Structures Inc., a construction firm for glulam owned by both the Hanisch and Thompson families.
A second project, this time for the Forest Products Laboratory (FPL), gave Unit Structures the opportunity to prove the strength and stiffness of glulam members to architects and engineers.
Full-scale load tests conducted by placing 14.3 tonnes (31,500 lb) of sandbags on the roof exceeded the design specs by 50%.
At this time, I-sections featuring plywood webs and glulam flanges became popular in Europe while rectangular sections became the norm in America.
In 1942, the introduction of a fully water-resistant phenol-resorcinol adhesive enabled glulam to be used in exposed exterior environments without concern of glue line degradation, expanding its applicable market.
In 1952, leading fabricators of engineered and solid wood joined forces to create the American Institute of Timber Construction (AITC) to help standardize the industry and promote its use.
After the resins have cured, the lumber is cut to length and planed on each side to ensure smooth surfaces for gluing.
For straight beams, the resinated lumber is stacked in a specific lay-up pattern in a clamping bed where a mechanical or hydraulic system presses the layers together.
[6] When glued laminated timber was introduced as a building material in the early twentieth century, casein glues (which are waterproof but have lower shear strength) were widely used.
[7] Also, there is today another technique for gluing green wood (of high moisture content) to fabricate such laminated products.
[9] Computer numerical control (CNC) allows to cut glued laminated timber into unusual shapes with a high degree of precision.
Prefabrication is invariably employed and the structural engineer needs to specify methods for delivery and erection of the large members at an early stage in the design.
Eastern Kentucky University's Alumni Coliseum was built in 1963 with the world's largest glued laminated arches, which span 93.967 metres (308 ft 3+1⁄2 in).
The Kingsway Pedestrian Bridge in Burnaby, British Columbia, Canada, is constructed of cast-in-place concrete for the support piers, structural steel and glulam for the arch, a post tensioned precast concrete walking deck, and stainless steel support rods connecting the arch to the walking deck.
[23] As an alternative to new-felled oak trees, glued laminated timber was proposed as the structural material in the replacement spire of Notre-Dame de Paris, destroyed by fire in 2019.
[24][25] Glulam is used extensively in public facilities due to its ability to span large spaces without the need for intermediate supports.
The exposed wooden beams can be crafted into elegant arches or intricate patterns, adding to the visual interest of the space.
Structural Strength: Glulam's high strength-to-weight ratio allows for the creation of large, open spaces free of columns or other supports that could obstruct views.
Versatility in Design: Glulam can be shaped into various forms, including curves and angles that traditional solid wood might not easily achieve.
[27] The roof of the Centre Pompidou-Metz museum in France is composed of sixteen kilometers of glued laminated timber intersecting to form hexagonal units.
[29] In January 2002 the roof of the Siemens velodrome arena in Copenhagen collapsed when a joint between glulam trusses failed at the point of its dowel fastenings.
