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Abstrakt

Durability is essential for outdoor structures to minimize life cycle costs. Timber beams and columns can get decay and cracks due to dimensional changes through shrinking and swelling by moisture changes during exposure. Cracks can lead water into wood and thereby increase the risk for decay and reduce strength and service life. This project deals with the assessment and prediction
of development for timber structures with cracks. More than 100 test specimens are included in an outdoor test, glulam beams and columns made of Scots pine (Pinus Silvestris) or Norway spruce (Picea abies). Most specimens are placed in the north of Sweden, but also some in the southwest of Sweden. The project started during 2007. The beams and columns are measured regularly concerning cracks and surface treatment, moisture content and modulus of elasticity on-site. Weather is measured. This paper describes tests and measurements and reports some initial results. The results so far show that cracks develop for every year. Some beams, preferable the oil treated ones, have already after three years lots of cracks while some of the painted are rather intact. The
moisture content and modulus of elasticity is relatively unchanged. The research will continue.

Referanser

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