Bearing capacity for timber parts with cracks Timber parts with cracks can be found now and then at the inspections of timber bridges. The question is how the bearing capacity should be calculated and judged for these parts, as well as how the cracks will develop under different circumstances. Cracks are a consequence of varying moisture content in the wood, and occur most often when the wood is exposed to sun and rainfall. The bearing capacity of timber is usually not directly affected by small cracks. The cracks have primarily influence on the moisture intrusion in the wood, which in course of time can affect durability and bearing capacity. The resistance of joints in timber structures can also be influenced by cracks in the wood. Structural parts in timber bridges can be protected against direct sunshine and rain by coverings, but in some bridges the wood is protected with surface treatment. Glulam structures with surface treatments that are exposed to weather often receive cracks on the surface, usually close to the glue lines. The cracks make the treatment less tight, which opens the way for water and fungi. A tight treatment makes it difficult for moistture in the wood to dry, and the influence of different treatments on the development of cracks and durability should also be investigated. The aim of this pilot project is to study the crack formation in timber parts and influencing factors in order to decide the bearing capacity and durability. The project work consists of a literature study, calculations, tests and evaluations of some beams. The result from the study will be presented in a report. The ambition is to form the basis for a continued more comprehensive research project.