A plyscraper, or timber tower is a skyscraper made (at least partly) of wood. They may alternatively be known as mass timber buildings.
A plyscraper, or timber tower is a skyscraper made (at least partly) of wood. They may alternatively be known as mass timber buildings.
There are four main types of engineered wood used for mass timber including cross-laminated timber (CLT), glued laminated timber (glulam), laminated strand lumber (LSL), and laminated veneer lumber (LVL). Of these three wood systems, CLT is the most commonly used. [1]
When other materials, such as concrete or steel, are used in conjunction with engineered wood, these plyscrapers are called “hybrids”. For hybrid buildings, there are some approaches to how different materials can be used including the “Cree’s System” which was developed by Cree Buildings, and the “Finding the Forest Through the Trees" (FFTT) construction model” developed by Michael Green. Cree's System combines the use of concrete and wood mainly in its hybrid flooring systems. In some instances, concrete can also be used as a core or for the foundation of a building because wood is too light. The FFTT construction model incorporates a wooden core and wooden floor slabs mixed with steel beams to provide ductility to the building. [1] [2]
When considering which engineered wood system to use for a plyscraper the individual benefits of each must be compared. CLT has a high fire resistance due to the fire-resistant adhesive used and the surface char layer that forms when it is exposed to fire. The surface char layer protects the interior of the wood from further damage. Glulam is typically used for columns and beams as an alternative to commonly used steel and concrete. [1] [3] This is because it has a greater tensile strength-to-weight ratio than steel and can resist compression better than concrete. LVL also has the same strength as concrete. [4] As plyscrapers are made from wood, they sequester carbon during construction and are renewable if the forests that they are sourced from are sustainably managed. [1] [3]
Despite these benefits, there are bound to be some drawbacks when using the various engineered woods. Steel overall has a greater strength and durability for the same sized profile when compared to its wood counterpart. [5] Thus, a building made with steel beams would require smaller beams than the same building constructed with wooden beams. Walls and columns in the interior spaces of these plyscrapers can get so thick that the size of said interior space gets heavily reduced. This issue however, does not occur within shorter buildings.
Over the years, many plyscrapers have been constructed, each becoming taller than the last. In 2017, the tallest habitable plyscraper was Brock Commons Tallwood House, on the campus of the University of British Columbia near Vancouver, Canada and measured 53 meters tall (174 feet). [6] It was overtaken in 2019, when the Mjøstårnet was built in Brumunddal, Norway. The Mjøstårnet measured 85.4 meters (280 ft). [7] However, in 2022, the title of the tallest habitable plyscraper shifted once again when the Ascent MKE Building, located in Milwaukee, Wisconsin was built measuring 86.56 meters (284 ft). [8]
The use of mass timber has been popular in Europe for a few years but has started to gain traction in the United States as knowledge of engineered woods has developed and experience with them as construction materials has increased. [9] Plyscrapers are still in their infancy stage, but as we learn more about mass timber and become more proficient using it, many mass-timber buildings are currently being proposed. In fact, they are becoming increasingly popular among contractors and builders due to the ease of construction, as putting together a plyscraper is faster and quieter compared to its steel and concrete counterparts. [8]
Several proposals to create more plyscrapers have been made all over the world. For example, in Tokyo, a plyscraper that is 350 meters (1,150 ft) tall called the W350 Project has been proposed with plans to be complete in 2041. [10] The W350 Project plans to be a hybrid plyscraper using only 10% steel and the remainder engineered wood. In London, research and planning are underway for the Oakwood Tower which is estimated to be 300 meters (980 ft) tall. [11] This would be an 80-story building integrated into the London skyline. In Chicago, there is a concept proposal for a 228-meter-tall (748 ft) building called the River Beech Tower. [2] The team designing this building plans to implement a system called the exterior diagrid system which would take advantage of the natural axial strength of timber allowing for efficient load distribution throughout the whole building.
A skyscraper is a tall continuously habitable building having multiple floors. Modern sources define skyscrapers as being at least 100 meters (330 ft) or 150 meters (490 ft) in height, though there is no universally accepted definition, other than being very tall high-rise buildings. Historically, the term first referred to buildings with between 10 and 20 stories when these types of buildings began to be constructed in the 1880s. Skyscrapers may host offices, hotels, residential spaces, and retail spaces.
Lumber is wood that has been processed into uniform and useful sizes, including beams and planks or boards. Lumber is mainly used for construction framing, as well as finishing. Lumber has many uses beyond home building. Lumber is referred to as timber in the United Kingdom, Europe, Australia, and New Zealand, while in other parts of the world the term timber refers specifically to unprocessed wood fiber, such as cut logs or standing trees that have yet to be cut.
Engineered wood, also called mass timber, composite wood, human-made wood, or manufactured board, includes a range of derivative wood products which are manufactured by binding or fixing the strands, particles, fibres, or veneers or boards of wood, together with adhesives, or other methods of fixation to form composite material. The panels vary in size but can range upwards of 64 by 8 feet and in the case of cross-laminated timber (CLT) can be of any thickness from a few inches to 16 inches (410 mm) or more. These products are engineered to precise design specifications, which are tested to meet national or international standards and provide uniformity and predictability in their structural performance. Engineered wood products are used in a variety of applications, from home construction to commercial buildings to industrial products. The products can be used for joists and beams that replace steel in many building projects. The term mass timber describes a group of building materials that can replace concrete assemblies.
Glued laminated timber, commonly referred to as glulam, is a type of structural engineered wood product constituted by layers of dimensional lumber bonded together with durable, moisture-resistant structural adhesives so that all of the grain runs parallel to the longitudinal axis. In North America, the material providing the laminations is termed laminating stock or lamstock.
This page is a list of construction topics.
A flitch beam is a compound beam used in the construction of houses, decks, and other primarily wood-frame structures. Typically, the flitch beam is made up of a vertical steel plate sandwiched between two wood beams, the three layers being held together with bolts. In that common form it is sometimes referenced as a steel flitch beam. Further alternating layers of wood and steel can be used to produce an even stronger beam. The metal plates within the beam are known as flitch plates.[1] Flitch beams were used as a cost-effective way to strengthen long-span wooden beams, and have been largely supplanted by more recent technology.
In structural engineering, the tube is a system where, to resist lateral loads, a building is designed to act like a hollow cylinder, cantilevered perpendicular to the ground. This system was introduced by Fazlur Rahman Khan while at the architectural firm Skidmore, Owings & Merrill (SOM), in their Chicago office. The first example of the tube's use is the 43-story Khan-designed DeWitt-Chestnut Apartment Building, since renamed Plaza on DeWitt, in Chicago, Illinois, finished in 1966.
Cross-laminated timber (CLT) is a subcategory of engineered wood panel product made from gluing together at least three layers of solid-sawn lumber. Each layer of boards is usually oriented perpendicular to adjacent layers and glued on the wide faces of each board, usually in a symmetric way so that the outer layers have the same orientation. An odd number of layers is most common, but there are configurations with even numbers as well. Regular timber is an anisotropic material, meaning that the physical properties change depending on the direction at which the force is applied. By gluing layers of wood at right angles, the panel is able to achieve better structural rigidity in both directions. It is similar to plywood but with distinctively thicker laminations.
Stadthaus is a nine-storey residential building in Hackney, London. At nine stories, it is thought to be the second tallest timber residential structure in the world, after the Forte apartment complex in Melbourne, Australia. It was designed in collaboration between architects Waugh Thistleton, structural engineers Techniker, and timber panel manufacturer KLH.
Framework was a planned mixed-use building in Portland, Oregon, United States, that would have been located in the Pearl District neighborhood. Designed by Lever Architecture, it would have been the tallest timber building in North America, and was called the "nation's first high-rise building made of wood". This project was cancelled in 2018 due to a funding shortfall.
Carbon12 is a wooden building in Portland, Oregon's Eliot neighborhood, in the United States. The eight-story structure built with Oregon-made cross-laminated timber (CLT) became the tallest wood building in the United States upon its completion.
Pres-Lam is a method of mass engineered timber construction that uses high strength unbonded steel cables or bars to create connections between timber beams and columns or columns and walls and their foundations. As a prestressed structure the steel cables clamp members together creating connections which are stronger and more compact than traditional timber fastening systems. In earthquake zones, the steel cables can be coupled with internal or external steel reinforcing which provide additional strength and energy dissipation creating a damage avoiding structural system.
Mjøstårnet is an 18-storey mixed-use building in Brumunddal, Norway, completed in March 2019. At the time of completion, it was officially the world's tallest wooden building, at 85.4 m (280 ft) tall, before being surpassed by Ascent MKE in August 2022. Mjøstårnet translates as "the tower of lake Mjøsa". The building is named after Norway's biggest lake, which is 100 km away from Oslo.
cadwork informatik CI AG is a multinational software company headquartered in Basel, Switzerland. It develops and markets software products primarily for the construction industry. These products include timber industry products in computer-aided design (CAD) and computer-aided manufacturing (CAM) as well as products in building information model (BIM) and virtual design and construction (VDC). These products are suitable for designers, structural engineers, construction engineers, civil engineering draftspeople, building contractors, and in the case of BIMTeam VDC, the construction crews.
Brock Commons Tallwood House is an 18-storey student residence at the Point Grey Campus of the University of British Columbia (UBC) in Canada. At the time it was opened, it was the tallest mass timber structure in the world.
Michael Green is a Canadian architect, co-founder of Michael Green Architecture which he leads with firm partner Natalie Telewiak, and an author of books on mass timber construction. The Case for Tall Wood Buildings is a case study on using materials such as cross-laminated timber panels and engineered glulam wood beams to build skyscrapers as tall as 30 storeys, originally prepared in 2012 by Green, Equilibrium Consulting, LMDG Ltd. and BTY Group. Green also coauthored Tall Wood Buildings: Design, Construction and Performance, which was published by Birkhäuser in 2017. In March 2020, Birkhäuser published the second and expanded edition of this book. In 2013, Green gave a TED talk titled “Why we should build Wooden Skyscrapers’. In 2014, Green received an honorary doctorate degree from the University of Northern British Columbia.
The W350 Project is a proposed wooden skyscraper in central Tokyo, Japan, announced in 2018. The skyscraper is set to reach a height of 350 meters with 70 floors, which upon its completion will make it the tallest wooden skyscraper, as well as Japan's tallest building. The skyscraper is set to be a mixed-used building including residential, office and retail space.
Ascent MKE is a mass timber hybrid high-rise apartment building in Milwaukee, Wisconsin. The 284-foot, 25-story high-rise is the world's tallest mass timber structure, edging out Norway's Mjøstårnet. It features 259 luxury apartments, retail space, an elevated pool with operable window walls, and a sky-deck.
Limberlost Place, formerly known as The Arbour, is a new addition to George Brown College's Waterfront Campus. It is set to open in summer 2024, and will be home to the college's architecture and computer technology students. With a planned occupancy for nearly 3,400 users, the 225,000 square-foot building will feature classrooms, study areas, staff support spaces, and a daycare facility. The is project designed by Moriyama & Teshima Architects alongside Acton Ostry Architects.