̽��ֱ�� of Cambridge - skyscrapers

Sowing seeds for timber skyscrapers can rewind the carbon footprint of the concrete industry

ehs33 — Fri, 28 Jun 2019 12:51:58 +0000

Recent innovations in engineered timber have laid the foundations for the world’s first wooden skyscrapers to appear within a decade, a feat that is not only achievable—according to the Centre for Natural Material Innovation—but one they hope will beckon in an era of sustainable wooden cities, helping reverse historic emissions from the construction industry.

̽��ֱ��research team based at the Faculty of Architecture, is interdisciplinary, composed of architects, biochemists, chemists, mathematicians and engineers, who specialise in plant-based material, including cross-laminated timber, arguably the first major structural innovation since the advent of reinforced concrete, 150 years ago.

Principal Investigator Dr Michael Ramage, said “Until cross-laminated timber, there was simply no building material to challenge steel or reinforced concrete. To construct cities and indeed skyscrapers, we just had to accept the good and the bad of existing materials.

“Concrete is about five times heavier than timber, which means more expense for foundations and transport; it’s resource-intensive, and contributes to tremendous carbon dioxide emissions. After water, concrete is the most consumed material by humanity. But now we have an alternative, and it’s plant-based.”

̽��ֱ��team envisage trees supplanting concrete as the predominant building material for cities, with buildings sown like seeds and cities harvested as crops, a way of simultaneously addressing climate change and global housing shortages.

Dr Ramage explained: “In England alone, we need to build 340,000 new homes each year over the next 12 years to accommodate our population. Concrete is unsustainable. Timber, however, is the only building material we can grow, and that actually reduces carbon dioxide. Every tonne of timber expunges 1.8 tonnes of carbon dioxide from the atmosphere. Doing the calculations, if all new English homes were constructed from timber, we could capture and offset the carbon footprints of around 850,000 people for 10 years.

“ ̽��ֱ��sustainable forests of Europe take just 7 seconds to grow the volume of timber required for a 3 bedroom apartment, and 4 hours to grow a 300 metre supertall skyscraper. Canada’s sustainable forests alone yield enough timber to house a billion people in perpetuity, with forested trees replenishing faster than their eventual occupants.”

Various teams around the world are hoping to produce the tallest wooden skyscraper, however the team from Cambridge is confident they’ll be the first, having done holistic work on three proposals for timber skyscrapers in London, Chicago, and the Hague, all of which are set to be showcased to the public at the Royal Society’s Summer Science Exhibition 2019, freely open to the public from July 1–7.

̽��ֱ��team’s exhibit—Timber towers of tomorrow—will embody their vision, the stand itself modelled after a typical apartment nested within their proposed Oakwood Timber Tower at the Barbican Tower, where visitors can experience life in a treehouse while talking with the team, viewing architectural models of timber towers, learning about the fire performance properties of engineered timber, and hearing about the genetic, cellular, and macroscale innovations which have led to ply in the sky designs becoming a reality.

Beyond tackling climate change and promoting sustainability, the team are eager to outline the branching benefits society stands to gain by embracing timber architecture: the psychological well-being that comes from being surrounded by wood as compared with concrete, as well as the return to an ancient building material, that’s intimate as it is natural.

A bold response to the world’s greatest challenge
̽��ֱ�� ̽��ֱ�� of Cambridge is building on its existing research and launching an ambitious new environment and climate change initiative. Cambridge Zero is not just about developing greener technologies. It will harness the full power of the ̽��ֱ��’s research and policy expertise, developing solutions that work for our lives, our society and our biosphere.

̽��ֱ��Centre for Natural Material Innovation exhibited their proposals for timber skyscrapers at the Royal Society’s Summer Science Exhibition.

Wooden skyscrapers: Sustainable homes of the future?

River Beech Tower Chicago

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Back to the future of skyscraper design

sjr81 — Wed, 01 Mar 2017 09:09:44 +0000

Newly-published, ̽��ֱ��Recovery of Natural Environments in Architecture by Professor Alan Short is the culmination of 30 years’ research and award-winning green building design by Short and colleagues in Architecture, Engineering, Applied Maths and Earth Sciences at the ̽��ֱ�� of Cambridge.

“ ̽��ֱ��crisis in building design is already here,” said Short. “Policy makers think you can solve energy and building problems with gadgets. You can’t. As global temperatures continue to rise, we are going to continue to squander more and more energy on keeping our buildings mechanically cool until we have run out of capacity.”

Short is calling for a sweeping reinvention of how skyscrapers and major public architecture are designed – to end the reliance on sealed buildings which exist solely via the ‘life support’ system of vast air conditioning units.

Instead, he shows it is entirely possible to accommodate natural ventilation and cooling in large buildings by looking into the past, before the widespread introduction of air conditioning systems which were ‘relentlessly and aggressively promoted’ by inventor Willis Carrier and rival entrepreneurs.

“ ̽��ֱ��majority of contemporary buildings have absolutely no resilience to climate at all,” he added. “To make them habitable, you have to seal them and air condition them. ̽��ֱ��energy use and carbon emissions this generates is spectacular and to a large extent unnecessary. Buildings in the West count for 40-50% of electricity usage, generating substantial carbon emissions. ̽��ֱ��rest of the world is catching up at a frightening rate, China at 31% and rising in 2017.

“Modern buildings cannot survive unless hard-wired to a life support machine, yet this fetish for glass, steel and air-conditioned skyscrapers continues; they are symbols of status around the world on an increasingly vast scale.”

Short’s book highlights a developing and sophisticated art and science of ventilating buildings through the 19th and earlier 20th centuries, including the two chambers of the Houses of Parliament, and the design of ingeniously ventilated hospitals. Of particular interest were those built under the aegis of John Shaw Billings, designer of the first Johns Hopkins Hospital in Baltimore (1873-1889).

“We spent three years digitally modelling Billings' final designs and a brilliant alternative design,” added Short. “We put pathogens in the airstreams, modelled for someone with TB coughing in the wards and we found the ventilation systems in the room would have kept patients safe from harm.

“We discovered that nineteenth century hospital wards could generate up to 24 air changes an hour– that’s similar to the performance of a modern-day, computer-controlled operating theatre. We believe you could build wards based on these principles for the NHS now. Single rooms are not appropriate for all patients. Communal wards appropriate for certain patients – older people with dementia, for example – would work just as well in today’s hospitals, at a fraction of the energy cost.”

Professor Short contends the mindset and skill-sets behind these designs have been completely lost, lamenting the disappearance of expertly designed theatres, opera houses, and other public buildings where up to half the volume of the building was given over to ensuring everyone got fresh air. Early twentieth century climate determinists like Ellsworth Huntington at Yale inadvertently promoted the export of cool, temperate climates around the world and explicitly condemned the inhabitants of hot climates as uncivilised and backward.

Much of the ingenuity present in 19th century hospital and building design was driven by a panicked public clamouring for buildings that could protect against what was thought to be the pernicious threat of miasmas – toxic air that spread disease.

Bad, malodourous air was considered lethal by huge swathes of the populace. Miasmas and other quasi-mystical phenomena were feared as the principal agents of disease and epidemics for centuries, and were used to explain the spread of infection from the Middle Ages, right through to the cholera outbreaks in London and Paris during the 1850s. Miasma theory attracted the attention of luminaries such as Florence Nightingale who believed that foul air, rather than germs, was the main driver of 'hospital fever' leading to disease and frequent death. ̽��ֱ��prosperous steered clear of hospitals.

While miasma theory has been long since disproved, Short has for the last thirty years advocated a return to some of the building design principles produced in its wake.

“ ̽��ֱ��air conditioning industry has persuaded us that you can’t do this naturally any more and that it would defy progress to do so. Huge amounts of a building’s space and construction cost are today given over to air-conditioning instead.

“But I have designed and built a series of buildings over the past three decades which have tried to reinvent some of these ideas and then measure what happens – publishing what works as well as what doesn’t.

“To go forward into our new low energy, low carbon future, we would be well advised to look back at design before our high-energy high-carbon present appeared. What is surprising is what a rich legacy we have abandoned. There is an analogy with the widespread introduction of affordable antibiotics and the relaxation in the ferocious cleanliness regimes in hospitals and the frightening consequences emerging now.”

Successful examples of Short’s approach include the iconic Queen’s Building at De Montfort ̽��ֱ�� in Leicester. Containing as many as 2,000 staff and students, the entire building is naturally ventilated, passively cooled and naturally lit, including the two largest auditoria each seating more than 150 people.

Conventional wisdom in the ventilation and heating industry was that this omission of mechanical and electrical equipment was impossible. Confounding its critics, the building was awarded the Green Building of the Year and RIBA’s Education Building of the Year in 1995 and was at the time the largest naturally ventilated building in Europe, influencing guidance in Europe and the USA. ̽��ֱ��building uses a fraction of the electricity of comparable buildings in the UK.

Following success there, Short and industry associates have also experimented with theatre design, including the Contact Theatre in Manchester, which uses the abundant heat sources of theatre lights and audience to drive air flows around the building and the passive downdraught cooled School of Slavonic and East European Studies in Bloomsbury, epicentre of the London Heat Island.

Short contends that glass skyscrapers in London and around the world will become a liability over the next twenty or thirty years’ time if climate modelling predictions and energy price rises come to pass as expected. He points to the perfect storm of the skyscraper boom in China, where huge high-rise, all-glass metropolises expand at an exponential rate. Meanwhile, 550 million people south of the Qin-Huai line in that country are not allowed to centrally heat or cool their own homes because of the energy that would demand and consume.

Short is convinced that sufficiently cooled skyscrapers using the natural environment can be produced in almost any climate, pointing to his research work on cooling an 11-storey tower at Addenbrooke’s Hospital in Cambridge. He and his team have also worked on hybrid buildings in the harsh climates of Beijing and Chicago – built with natural ventilation assisted by back-up air-conditioning – which, surprisingly perhaps, can be switched off more than half the time on milder days and during the spring and autumn.

“I think you can upscale these designs,” he added. “As you go higher, airspeeds increase and it becomes easier to control the climate within tall buildings.

“My book is a recipe book which looks at the past, how we got to where we are now, and how we might reimagine the cities, offices and homes of the future. There are compelling reasons to do this. ̽��ֱ��Department of Health says new hospitals should be naturally ventilated, but they are not. Maybe it’s time we changed our outlook.”

̽��ֱ��Recovery of Natural Environments in Architecture: Air, Comfort and Climate, published by Routledge, is out now.

Answers to the problem of crippling electricity use by skyscrapers and large public buildings could be ‘exhumed’ from ingenious but forgotten architectural designs of the 19th and early 20th century – according to a world authority on climate and building design.

̽��ֱ��air conditioning industry has persuaded us that you can’t naturally ventilate buildings any more.

Alan Short

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Post-war advertisement for air conditioning by Carrier

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Would you live in a city made of bone?

sc604 — Thu, 23 Jun 2016 13:47:51 +0000

Between them, concrete and steel are responsible for as much as a tenth of worldwide carbon emissions. Before they ever reach a construction site, both steel and concrete must be processed at very high temperatures – which takes a lot of energy. And yet, our cities are completely dependent on these two unsustainable materials.

“I fly back and forth a lot between the UK and the US, and I’d been harbouring a lot of guilt about the effect that had on my carbon footprint – I’d always assumed, as many of us do, that air travel is a huge contributor to carbon emissions,” says bioengineer Dr Michelle Oyen of Cambridge’s Department of Engineering. “But the truth is, while the emissions caused by air travel are significant, far more are caused by the production of concrete and steel, which of course is what most cities are built from.”

So what does that mean for cities of the future, as more and more of us live in urban areas? How can we continue to build while reducing carbon emissions?

Whereas some researchers are investigating ways of producing steel and concrete in more energy-efficient ways, or finding ways of using less, Oyen would rather turn the tables completely, and create new building materials that are strong, sustainable and take their inspiration from nature.

“What we’re trying to do is to rethink the way that we make things,” says Oyen. “Engineers tend to throw energy at problems, whereas nature throws information at problems – they fundamentally do things differently.”

Oyen works in the field of biomimetics – literally ‘copying life’. In her lab, with funding support from the US Army Corps of Engineers, she constructs small samples of artificial bone and eggshell, which could be used as medical implants, or even be scaled up and used as low-carbon building materials.

Like the real things, artificial bone and eggshell are composites of proteins and minerals. In bone, the proportions of protein and mineral are roughly equal – the mineral gives bone stiffness and hardness, while the protein gives it toughness or resistance to fracture. While bones can break, it is relatively rare, and they have the benefit of being self-healing – another feature that engineers are trying to bring to biomimetic materials.

In eggshell, the ratios are different: about 95% mineral to 5% protein, but even this small amount of protein makes eggshell remarkably tough considering how thin it is.

When making the artificial bone and eggshell, the mineral components are ‘templated’ directly onto collagen, which is the most abundant protein in the animal world. “One of the interesting things is that the minerals that make up bone deposit along the collagen, and eggshell deposits outwards from the collagen, perpendicular to it,” says Oyen. “So it might even be the case that these two composites could be combined to make a lattice-type structure, which would be even stronger – there’s some interesting science there that we’d like to look into.”

In her lab, Oyen and her team have been making samples of artificial eggshell and bone via a process that could be easily scaled up – and since the process takes place at room temperature, the samples take very little energy to produce. But it may be some time before we’re living in bone and eggshell houses.

For one, the collagen that Oyen needs to make these materials comes from natural (meaning animal) sources. One of the things she’s currently investigating is whether a non-animal-derived or even synthetic protein or polymer could be used instead of natural collagen.

“Another issue is the construction industry is a very conservative one,” Oyen says. “All of our existing building standards have been designed with concrete and steel in mind. Constructing buildings out of entirely new materials would mean completely rethinking the whole industry. But if you want to do something really transformative to bring down carbon emissions, then I think that’s what we have to do. If we’re going to make a real change, a major rethink is what has to happen.”

Dr Michael Ramage from the Department of Architecture is another Cambridge researcher who believes we need to expand our use of natural materials in buildings. Ramage has several ongoing research projects that are looking into the use of wood – one of the oldest building materials we have – for tall buildings.

Working with PLP Architecture and engineers Smith and Wallwork, Ramage recently delivered plans for an 80-storey, 300 m high, timber skyscraper to the Mayor of London. ̽��ֱ��proposals currently being developed would create more than 1,000 residential units in a 1 million square-foot, mixed-use tower and mid-rise terraces, integrated into the Barbican in central London.

Like other natural materials, the primary benefit of using wood as a building material is that it is a renewable resource, unlike concrete and steel. Ramage’s research is also investigating other potential benefits of using wood for tall buildings, such as reduced costs and improved construction timescales, increased fire resistance and a significant reduction in the overall weight of buildings.

“If London is going to survive an increasing population, it needs to densify,” says Ramage. “One way is taller buildings. We believe people have a greater affinity for taller buildings in natural materials rather than steel and concrete towers. ̽��ֱ��fundamental premise is that timber and other natural materials are vastly underused and we don’t give them nearly enough credit. Nearly every historic building, from King’s College Chapel to Westminster Hall, has made extensive use of timber.”

̽��ֱ��tallest timber building in the world at the moment is a 14-storey apartment block in Bergen, Norway, but Ramage foresees future cities where timber skyscrapers sit alongside those made of concrete and steel.

“Future cities may not look a whole lot different – you may not know immediately if you are in a timber, steel or concrete building,” says Ramage. “But cities might be a whole lot quieter, as most timber buildings are built off site, and then just assembled on site, and use roughly a fifth as much truck traffic as equivalent concrete buildings. In other words, what needs to be delivered in five trucks for a concrete building can be delivered in one truck for a timber building. That’s an incredible advantage, for cost, for environment, for traffic and for cyclists.”

“ ̽��ֱ��material properties of bone and wood are very similar,” says Oyen. “Just because we can make all of our buildings out of concrete and steel doesn’t mean we should. But it will require big change.”

̽��ֱ��cities of today are built with concrete and steel – but some Cambridge researchers think that the cities of the future need to go back to nature if they are to support an ever-expanding population, while keeping carbon emissions under control.

Just because we can make all of our buildings out of concrete and steel doesn’t mean we should. But it will require big change

Michelle Oyen

Abdul Rahman

City

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Timber skyscrapers could transform London’s skyline

sjr81 — Fri, 08 Apr 2016 08:33:58 +0000

Researchers from Cambridge ̽��ֱ��’s Department of Architecture are working with PLP Architecture and engineers Smith and Wallwork on the future development of tall timber buildings in central London.

̽��ֱ��use of timber as a structural material in tall buildings is an area of emerging interest for its variety of potential benefits; the most obvious being that it is a renewable resource, unlike prevailing construction methods which use concrete and steel. ̽��ֱ��research is also investigating other potential benefits, such as reduced costs and improved construction timescales, increased fire resistance, and significant reduction in the overall weight of buildings.

̽��ֱ��conceptual proposals currently being developed would create over 1,000 new residential units in a 1 million sq ft mixed-use tower and mid-rise terraces in central London, integrated within the Barbican.

Dr Michael Ramage, Director of Cambridge’s Centre for Natural Material Innovation, said: “ ̽��ֱ��Barbican was designed in the middle of the last century to bring residential living into the city of London – and it was successful. We’ve put our proposals on the Barbican as a way to imagine what the future of construction could look like in the 21st century.

“If London is going to survive it needs to increasingly densify. One way is taller buildings. We believe people have a greater affinity for taller buildings in natural materials rather than steel and concrete towers. ̽��ֱ��fundamental premise is that timber and other natural materials are vastly underused and we don’t give them nearly enough credit. Nearly every historic building, from King’s College Chapel to Westminster Hall, has made extensive use of timber.”

Kevin Flanagan, Partner at PLP Architecture said “We now live predominantly in cities and so the proposals have been designed to improve our wellbeing in an urban context. Timber buildings have the potential architecturally to create a more pleasing, relaxed, sociable and creative urban experience.

“Our firm is currently designing many of London’s tall buildings, and the use of timber could transform the way we build in this city. We are excited to be working with the ̽��ֱ�� and with Smith and Wallwork on this ground breaking design- and engineering-based research.”

̽��ֱ��tall timber buildings research also looks towards creating new design potentials with timber buildings, rather than simply copying the forms of steel and concrete construction. ̽��ֱ��transition to timber construction may have a wider positive impact on urban environments and built form, and offers opportunities not only to rethink the aesthetics of buildings, but also the structural methodologies informing their design as well.

Just as major innovations in steel, glass and concrete revolutionised buildings in the 19th and 20th centuries, creating Joseph Paxton’s Crystal Palace and the Parisian arcades described by Walter Benjamin, innovations in timber construction could lead to entirely new experiences of the city in the 21st century.

̽��ֱ��type of wood these new buildings would use is regarded as a ‘crop’. ̽��ֱ��amount of crop forest in the world is currently expanding. Canada alone could produce more than 15billion m³ of crop forest in the next 70 years, enough to house around a billion people.

At present, the world’s tallest timber building is a 14-storey apartment block in Bergen, Norway. ̽��ֱ��proposals presented to Johnson included concepts for a timber tower nearly 300m high, which would make it the second tallest building in London after ̽��ֱ��Shard.

Dr Ramage added: “We’ve designed the architecture and engineering and demonstrated it will stand, but this is at a scale no one has attempted to build before. We are developing a new understanding of primary challenges in structure and construction. There is a lot of work ahead, but we are confident of meeting all the challenges before us.”

Perhaps the most obvious concern for potential residents of homes built primarily from timber is fire risk. However, the team involved in the project said the proposed building would eventually meet or exceed every existing fire regulation currently in place for steel and concrete buildings.

Recent research has also shown that timber buildings can have positive effects on their user and occupant’s health. Some recent studies have also shown that children taught in schools with timber structures may perform better than in those made of concrete.

̽��ֱ��designs for the Barbican is the first in a series of timber skyscrapers developed by Cambridge ̽��ֱ�� in association with globally renowned architects and structural engineers with funding from the UK’s Engineering and Physical Sciences Research Council.

London’s first timber skyscraper could be a step closer to reality this week after researchers presented Mayor of London Boris Johnson with conceptual plans for an 80-storey, 300m high wooden building integrated within the Barbican.

If London is going to survive it needs to increasingly densify. One way is taller buildings. We believe people have a greater affinity for taller buildings in natural materials rather than steel and concrete towers.

Michael Ramage

Conceptual image of how the building would look as viewed from the River Thames

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