The decision to use timber was due to its many potential benefits, such as it being a renewable and sustainable resource, reducing more carbon emissions than those of steel and concrete, providing increased fire resistance, reducing construction cost due to decrease in dead weight of the superstructure, providing aesthetical appeal, and reducing construction times and noise.
Using innovative structural engineering strategies, the 80 storey timber skyscraper project will validate the advantages of using engineered wood products over traditional reinforced concrete and steel. This first timber skyscraper will be setting a precedent on future timber skyscraper projects and pioneer the popular use of wood for years to come.
Our engineering expert bloggers at Sturdy Structural had the privilege of having an exclusive interview with the engineers at Smith and Wallwork on the 80 storey high timber skyscraper. Thank you, PLP Architecture, Smith and Wallwork, and the University of Cambridge for this wonderful opportunity and learning experience!
Its quick and quite to build with. It is a lightweight form of construction that can maximise the advantages of prefabrication.
What type of engineered wood would the project use?
The project would use engineered timber, with the volumes proposed we are looking at structural softwood such as spruce. In some of the high stress areas we would considered using higher grade timbers. The tower structural design relies on the stiffness of timber as well as strength. In this respect using a higher strength timber does not solve some of the tower sway challenges.
What are some mechanical properties and failure types of timber that would be an area of concern to this project?
Timber is a complex material and the size of elements that a tower of this size require have not been used before in buildings. We would have to carry out new research and testing of large scale timber elements and their connections. We would also look to learn from timber bridge building techniques where significant structures have been built in Scandinavia and central Europe.
What sort of construction methods will you use to construct the skyscraper?
The design takes advantage of the positives of building with timber; a quicker and quieter construction process is expected. Timber elements would be delivered to site in pre-fabricated elements, minimising the number of site connections where possible.
What are the different treatments for chemical attacks, for exposure to moisture, and for resisting fire that would be used for the timber products in this project? How would the timber be kept in adequate quality during operations and maintenance?
The structural timber would be contained within the façade of the building, not exposed to the external environment. Moisture control during construction would need to be controlled. Large scale timber elements have an inherent fire resistance and as such opportunity would exist to exposed the timber structure as part of the building architecture.
How does the load path of the skyscraper look like? What are the main lateral resisting system and its supporting foundation type? How will they be connected for the load to transfer?
The structure is based on a buttressed mega-truss design to resist lateral loads and also to shed load to the perimeter of the building. The lightweight nature of the structure allows us to take advantage of foundation savings. Foundation designs would be based around a deep piled raft, where possible all within the footprint of the tower.