Multi-storey mixed-purpose timber housing

Sammanfattning: Since ancient years, wood has been an important construction material. In the Nordic countries, like e.g. Sweden, timber has an essential role and more than 90% of all single family houses are built with timber. Another situation is for multi-storey buildings where the market for timber is about 7% in Sweden, and most of these buildings are two-storey only. The reason for this is that timber has been disqualified for a long time in construction of multi-storey houses by restrictive fire regulations imposed after a number of Swedish cities were burned down in the late 19th century. Today the Swedish government has created a strategy to increase the use of timber in multi-residential and commercial buildings.

Nowadays, on the current Swedish market, there are three types of building systems for multi-storey timber buildings. The panel system is based on pre-fabricated planar building elements like walls or floor elements. The volumetric system is principally utilizing the light frame system or solid wood, and the whole volumetric units are assembled off-site and transported to the building site for erection. These systems are mainly used for residential buildings, student apartments, and buildings like schools and offices. The beam and post system is common for industrial and commercial halls because it is suitable for large span structures. It is a system based on a load-bearing net of beams and columns.

This Master thesis presents a conceptual and structural design of a multi-storey building combining two different timber based building systems. The first two floors will be built in a new post and beam system called trä8 developed by company Moelven Töreboda. The remaining three storeys will be built using volumetric modules. It will allow making mix buildings with large spans in the bottom of them, for commercial uses, and dwellings in the top part.

The used methodology consists in, firstly, some hand calculations to learn how to design in timber structures in a traditional/conservative way and, secondly, the computer calculations were performed with the use of Finite Element software, FEM- Design, to analyze the connection between trä8 and volumetric system. Moreover, literature study was performed to achieve the basic knowledge to perform the above calculations.