The story of glulam’s success
The first glued laminated timber construction we know of as of today is the meeting hall of the King Edward College in Southampton in 1860. In 1906, Otto Hetzer acquired the patent DRP No. 197773 for curved, glued laminated beams composed of two or more lamellas which are also inextricably glued under moisture.
With the Hetzer construction method one no longer had to stick with the length or cross section requirements of the component imposed by the nature of trunk diameter. Weaker timber could be processed in static and design aspects in a desired form into long-span structures. Otto Hetzer had consequently exploited these advantages. The structures were dimensioned according to the static stress, and almost always had beam heights corresponding to static stress, by consistent belt cross-sections. The cross-section was always an I-section.
The Hetzer construction method, discovered in the beginning of the previous century, revolutionized timber construction and triggered a new era of building with timber. The production of timber components spanned up to 40 meters was now possible, in contrast to traditional carpenters constructions.
For a long time no one knew any highly durable and at the same time rigid joining means. Hetzter solved the problem in this way: he glued multiple individual cross sections, with which the twisting and tearing of thin-walled wood cross sections could be prevented, and he developed a glue that was stronger than the wood itself.
Remarkable buildings in Glulam
- German railway hall for the World Exhibition in Brussels 1910
- Elephant House in Cologne (Köln)
- Bridge over the Main-Danube Canal near Essing
- Swimming pool Ensched
- Earth's magnetic field simulator for the German
- Marine in Rendsburg
- Expo roof at the Hanover Fair
Hüttemann buildings in Glulam
Hetzer's technology was further developed in the second half of the 20th century into today's glued laminated timber, for the production of which mostly European spruce is used. The boards are first kiln dried in large drying chambers in the wood gluing plant three to four days at a temperature of about 70 degrees Celsius. As the humidity in the buildings is about 11%, the boards are dried to this value, in order to later avoid major changes in humidity during their use.
Modern glued laminated timber, a technologically demanding product, has established itself as a building material especially for buildings with large span lengths over 100 m. With glulam any desired shapes, like in the saltwater pool in Bad Schwartau, the indoor swimming pool in AquaFun Soest, and the Elephant House in Cologne can be implemented. It allows column-free roofing of large sports facilities, as in the 60 m x 120 m large SAP Arena in Mannheim. With glued laminated timber numerous bridges are built, an outstanding example of which is a 200 m long and 73 m cantilevered pedestrian bridge over the Main-Danube Canal in Essing.
The technology in glulam construction is continually progressing. To connect fully utilized new components, particularly sustainable connection means are developed. Steel fasteners or high-strength plastics can be glued and allow the transmission of greater forces than it was possible with conventional fasteners. Fully automatically controlled joinery and processing machines provide millimeter cuts of any shape with never seen before accuracy. These developments give the high-tech product of glued laminated timber enhanced application areas, with virtually unlimited potential.