Thousands of years ago, wood was the second most popular building material after stone. In fact, if we go back to the history of the first human beings, they lived in the woods. So, we can say that wood is our ancestral heritage that is again gaining popularity in the modern world of smart cities.
The use of sustainable materials for constructing buildings is not a new concept. But the current scenario, where urban areas are facing the detrimental rise in carbon emissions and intensive use of non-renewable energy, the urge to use environment-friendly materials is rapidly increasing. The smart cities are attempting to focus on using materials that reduce the energy we use in operating buildings while heating, cooling, and lighting. The Royal Institute of Chartered Engineers reports that the building materials contributes towards a high percentage of the carbon footprint from a typical modern office building – concrete and steel make up an enormous amount of it. Also, the fact is, that skyscrapers are more material hungry as they need extra structure to fight stress, wind, and earthquakes. So, here comes the real need where towers need to change with what they are built.
Therefore, to meet the existing challenges and to reinvent the use of earth-friendly and sustainable materials in the building, the Australian Smart Skyscrapers Summit 2018 is coming up with the best use of Timber in construction of high-rises. What makes timber the ideal choice for skyscrapers can be seen in the context discussed further.
The Human Element of Timber Tower Buildings
Wood is a natural living material and the first ever building material used by mankind. When living or working in a space made out of wood, we feel an emotional and physical connection with its aesthetics. Our senses spiritually make us feel that wood is good.
Unlike steel and concrete, wood grows from the earth and is 100% renewable. Not to mention, it is environment-friendly and non-polluting. It does not require a huge amount of fossil fuels and harmful emissions for its production just like other man-made building materials. Wood is extremely durable and equally strong.
Let us first take the example of the biggest wooden high-rise project of the future in Tokyo, Japan. The world’s largest timber tower, a 350-meter (70-story) tall skyscraper is being planned to be built in Tokyo centre by 2041.
The timber tower will be a hybrid structure of wood and steel with 90% of it made from wooden materials. The building will adopt a green concept where the greenery will connect from the ground to the top floor and through the balconies, offering a natural landscape in the urban setting. The interior of the building will be entirely built from pure timber, giving a cozy and warm feeling to the users. The high-rise will consist of stores, offices, hotels as well as residences in an area of 6,500 meters.
In addition, the high-rise will focus on enhancing fire and seismic resistance along with durability. The cost of construction will be reduced and trees will be grown that will be used as resources.
Such skyscrapers have tremendous benefits to offer to its users. They provide a pleasant and comfortable space for everyone to live, work and relax. They compose a natural habitat for both plants and living organisms just like a forest. The network of greenery in such buildings, attracts wild birds and insects, contributing to a unique example of biodiversity in smart cities.
Now, let us look at the existing example of Timber high-rise in Australia, which will be one of the important case studies highlighted during the Australian Smart Skyscrapers Summit.
EY Centre at 200 George Street, Sydney received a highly commended award at the World Architecture Festival (WAF) in 2017. The structure is designed by FJMT and developed by Mirvac. It is a 37-story skyscraper that sets an example of having achieved design quality and sustainability.
The high-rise is a conventional office block that has been constructed with natural products like timber, clear glass and stone that produce a warm feel. The uniqueness of the structure comprises in automated timber blinds and vertical shading panels that naturally balance with the external environmental factors. The multi-million dollar tower is designed in such a way that the round towers overlap with a timber and glass facade. The building optimizes energy and workspace efficiency while giving a human touch to space.
Upon completion, the structure received the pride of being the new breed of innovative and highly sustainable smart buildings in Australia.
A New Type of Timber – Advancements in Tall Timber Buildings
Constructing a timber tower means that it would be far lighter than concrete and steel. It would cost less and use less material in its foundations. However, although timber is highly eco-friendly, it is a wood, and wood burns which raises the questions for safety. But we have a new solution for that in the form of mass timber. Mass timber such as CLT is different in physical properties compared to traditional timber. For example, when the mass timber is exposed to fire, the exterior layer burns and turns into charcoal. Further, the charcoal layer acts as a protective barrier that absorbs heat and insulates the inner layer of timber. As exposure to fire increases, the charcoal layer burns further, while slowing down the burning rate. This fact is proven in an aftermath of a forest fire where the trunk of trees charred and turned black but the interior was still alive and living. This physical property of mass timber is highly beneficial in constructing timber buildings.
Furthermore, engineered wood products like Cross Laminated Timber (CLT), Glued Laminated Timber (Glulam), and Structural Composite Lumber (SCL) like Laminated Veneer Lumber (LVL), Laminated Strand Lumber (LSL) and Parallel Strand Lumber (PSL) are highly reliable, sustainable and safe. They offer powerful strength and consistent quality. One of the best parts is that with these materials, the level of fire resistance is predictable.
More specifically, the features of Cross-laminated Timber provide the state-of-the-art performance when used in constructing high-rises. CLT is extremely easy to process. It can be prefabricated and just brought to site for easy and quick installation. Hence, on-site hurdles are very low while generation of waste is next to zero. Also, due to is its relative strength and lightweight, it can be essentially used in filling gaps in the existing buildings or construction projects.
CLT can be used in the construction of detached and semi-detached houses, multi-story buildings, schools, commercial or religious institutions – for walls, ceilings, and roofs.
Another aspect of engineered wood such as CLT is that it is highly earthquake stable. The flexibility of advanced wood buildings allows them to sway during an earthquake instead of getting shattered – must-needed feature for skyscrapers. A test was conducted in Kobe Japan where a seven-story wood-framed condominium tower escaped a 7.5 magnitude earthquake with just a scratch. Hence, if properly designed engineered wood can substantially withstand the effect of the earthquake.
CLT and other mass timber products are the potential building materials which are not just environmentally and physically responsible but are also economical. They can help us enhance our natural landscape in smart cities and make the urban space more energy efficient.
Timber has the capability to absorb carbon dioxide through photosynthesis. These can easily stand as the living epitome of structures in smart cities.
To know more about timber and timber skyscrapers, visit the Australian Smart Skyscrapers Summit 2018 in Sydney this year. It is preparing to solve the global problems with innovation, technology, and foresightedness.