The author’s intention is to contribute to the general discussion on timber multi-level commercial buildings. Interest in this topic is expected due to the environmental advantages of timber construction when compared to concrete and steel. This paper looks into three timber based systems for resisting lateral loads for buildings to six storeys, that will ensure relatively ‘open’ floor spaces. In this paper, three proposed lateral load resisting systems are termed ‘frame’, ‘circular core’, and ‘shear walls’. Only low stresses occur in the three systems and they can be made with timber below ‘structural grade’ which is more economical. The concept of reinforced concrete ‘socket’ foundations, for returning columns to their original locations, is briefly explained. The paper considers the lateral load resisting systems from the viewpoints of structure, architecture and economics. Architecturally, the most flexible arrangement would be a ‘frame’ system on each external wall. It would leave the floor areas free except for internal columns; and windows can be placed within the frame construction allowing light to enter the building. Assumptions have been made, such as the deflections due to joint slippages and these will, at some stage, need to be studied and their accuracy checked.
This research involves testing for a new structural system based on CLT (cross-laminated timber) panels to provide taller, economical and more useful timber high-rise buildings. The point of difference of the system compared to recently constructed CLT high-rise buildings is a central core which is comprised of vertically aligned but integrated CLT panels. The central core, which runs the full height of the building, is effectively a very large vertical cantilever with a rectangular hollow section, and is the main element for resisting lateral forces. This arrangement produces taller timber buildings with more open floor areas. For seismic events, the core is designed to a ‘damage avoidance philosophy’, to re-centre, and to minimise costs of building repair. The testing reported in the paper is for the ‘fuse’ connections of the core to the foundations which are designed to be ‘replaced in place’ and provide the required ductility to the timber which is a nonductile building material.
A worldwide interest in timber multi-storey buildings is expected due to the environmental advantages of timber construction when compared to buildings in concrete and steel. Cross-laminated Timber, or CLT, was developed in the early 1990’s and glues and clamps timber planks in alternate layers to form large panels. The cross-laminating ensures reliable strength and stability. CLT construction has been used successfully for the nine storey Murray Grove Stadhaus building in London and the ten storey Forte building in Melbourne. The paper proposes a new type of structural system that utilises CLT for buildings to twenty levels. The floor plan with a central rectangular core and columns at the perimeter is similar to a typical RC commercial building. There are considerably more open spaces than for existing CLT multi-level buildings which rely on multiple shear walls.
This research investigates a new structural system based on a central core of CLT (cross-laminated timber) panels to provide more useful multi-level timber buildings that are taller and with open floor areas. Because pinus radiata is a suitable timber for the manufacture of CLT panels, the system has the potential to add value to planted NZ forests and to earn overseas currency. Timber elements are proposed for the entire building structure – central core, columns, floor beams and floor joists. The vertical timber core is a very large square (or rectangular) hollow section that extends the full height of the building and is the main element for resisting lateral forces. Various aspects of the system are discussed in the paper. An analysis of the structure is reported and the paper concludes that the proposed structural system with CLT elements is suitable for buildings to at least twenty levels.