The research field Historic structures at the Department of Building Technology focuses mainly on historic wood and masonry constructions built using a pre-industrial technology.
Historic masonry constructions
The need for research in the field of historic masonry structures in Sweden is partly about them as load-bearing structures and partly about material technical problems in the masonry. As load-bearing structures, masonry structures differ in principle from those of steel, wood and reinforced concrete, which can carry load by tension. This means that the calculation methods and tools normally used by structural engineers are not applicable when masonry structures are to be analyzed.
Today, computer-based analysis methods based on thrust line analysis are being developed. These provide new opportunities to analyze and describe the mode of action, which we see a great need for in various assignments.
The material technical problems are due to the fact that there is a profound degradation following the extensive restorations of the 20th century using cement joints on ruins and churches. Thus, there is a great need to scientifically describe the problem, develop methods for inventory and evaluation, map and evaluate material properties, and define methods and materials for measures.
Historic wooden constructions
In Sweden, there are a large number of roof constructions of wood from the Middle Ages that have carried their load and functioned for more than 500 years, in some cases as long as for 900 years. This cultural heritage is unique in an international perspective in many ways.
If we move closer to our time, there are a large number of roof constructions preserved and in original function from the 17th, 18th and 19th centuries. These time horizons are completely different from the economic lifetimes that are mentioned in construction today. The structures are also built with renewable materials and they also function as carbon sinks. In today's situation of critical climate change at the door, we should be able to learn a lot from these, from several perspectives, very long-term sustainable structures.
The preservation of our oldest roof constructions can be put in relation to the museum preservation of our cultural heritage, where the clearest counterexample is the royal ship Vasa and the Vasa Museum. When Vasa made its maiden voyage in the 17th century, the roof structure of the Forshem church had supported the roof for almost 500 years. A central issue is thus how we can make the conditions more museum-like for the oldest wooden constructions, to ensure their preservation in the environment they are in.
When preserving historic wooden structures, a recurring problem is whether it is possible to rely on the strength of traditional carpenter's connections that are locked with wooden dowels, wedges and/or forged nails. When restoring historic timber structures, it is often desirable to use techniques and materials that are consistent with those used in the structure when it was erected, which means that studies of this type of structures are needed.