Higher timber buildings are produced around the world. The interest for higher timber buildings has increased. Design in ultimate limit state is well known, but little focus has been put on serviceability limit state especially on higher timber buildings. In this report result from interviews with structural engineers/designers, timber frame suppliers, and development managers are presented. The focus has been on serviceability limit state in mid-rise timber buildings. The experience and knowledge with the respondents varies, which has given a wide perspective of the area. Some of the outcomes are summarised here:
Stabilisation and stiffness will be an important aspect when it comes to building/designing higher timber buildings. Large deformations both in vertical and horizontal directions can be an issue due to increased weight and wind load respectively but the main focus should be on acceleration and comfort criteria.
Dynamic properties will according to several respondents be a challenge and several of them questioned how to make dynamic calculations and determine damping properties of a timber building.
Connections are a crucial link and it is important to find good solutions. In general all respondent argued that connections are the weakest link but the behaviour of the connection is difficult to predict.
Comfort criteria on timber floors has shown not to be satisfying due to human sensitivity to motion. Pilot projects have shown that stiffer floors are to recommend satisfying human comfort.
Criteria regarding horizontal deformations were pointed out as missing in Eurocode but best practice was used by several of the respondent. Some criteria regarding horizontal deformation and comfort criteria due to vibration can be found in other standards and was used by some of the respondents. Criteria can also be posed by e.g. a glass supplier.
Higher timber buildings will be built and dynamic properties will be the main design focus. Analyses and measurements of the natural frequencies and the damping of existing buildings are needed to increase knowledge.
