Development of dry composite construction systems based on steel in residential applications

This Final Report of the ECSC Project "Development of Dry Composite Construction Systems Based on Steel in Residential Applications", addresses new forms of construction in which light steel members and sheeting are designed to act compositely with 'dry' materials, such as boards and gypsum products. The research covers the composite action of light steel frames with floor and wall boarding, the development of timber steel composites for roofing, and cladding-frame interaction in typical housing with brick facades. The results of the various parts of the project are described as follows: A review of requirements and standards in the participating countries has been undertaken. This shows substantial differences between the countries, partially due to climatic differences but also due to different traditions. The use of light steel in housing varies also considerably between the countries, but is increasing in Scandinavia, France and UK. Building components of light steel, such as floors, external and internal walls have been studied concerning their general design and their functionality in different respects such as load bearing resistance, fire resistance, stiffness, vibrations, acoustics, thermal and hygrothermal performance. The components were tested in laboratory and also in completed buildings to compare with lab test results. Floors The floors studied have C- or Z-profiles as beams and different boards as surface material. The cavity is usually filled with mineral wool in order to improve the acoustic performance. Practical behaviour is governed by vibration limitations and design guidance for vibration control is given, which is deemed satisfactory for single family houses. For multi-storey buildings, expectations of the tenants are higher and stricter limitations may be needed. Measures to increase the stiffness have been studied such as improving lateral load distribution, embedding floor joists into brick walls and gluing the joints in the floor boarding. As the span increases above 6-7m, it becomes increasingly difficult to find practical solutions. A damping device has been developed and tested in the project and it may be one way to achieve longer spans. Fire tests have been performed and solutions for REI 30 and 60 are available. The acoustic performance has been tested with airborne sound and impact sound. In order to obtain a good sound insulation, it is necessary to have many layers in the floor element. One efficient solution is to use a suspended ceiling with flexible hangers. An analytical model for predicting the impact sound insulation has been developed. External walls Various forms of constructions based on studs, mineral wall and boards have been developed in which some insulation is placed external to the frame and some between the studs. The different walls have been studied regarding thermal and hygrothermal properties as well as airborne sound insulation. The heat resistance calculations have been performed with different methods which has given the opportunity to compare 2D and 3D calculations.