World's tallest timber tower gets go ahead

Materials World magazine
,
1 Sep 2016

The tallest timber tower

The world’s tallest timber tower, standing at 240ft, 21 storeys high, will be built in Amsterdam as part of the city’s bid to become carbon neutral. Team V Architectuur hopes to begin construction of the tower, named HAUT, in the latter half of 2017.

In keeping with the theme of environmentalism, Team V Architectuur aims to store three million kilograms of CO2 within the cross-laminated timber used to build HAUT. The architectural firm has also stated that the tower will include ‘energy-generating façades’, although further information has not yet been made available. In addition to the collection and purification of wastewater, Team V Architectuur is aiming for a BREEAM Outstanding rating for HAUT.

However, Team V Architectuur’s claim to the world’s tallest timber high-rise could be challenged should a PLP Architecture and the University of Cambridge-designed concept for a 984ft timber tower be approved for construction in London.

Dr Michael Ramage, Director of Cambridge University’s Centre for Natural Material Innovation, said, ‘If London is going to survive, it needs to increasingly densify. We believe people have a greater affinity for taller buildings in natural materials rather than steel and concrete towers. The fundamental premise is that timber and other natural materials are vastly underused and we don’t give them nearly enough credit.’

The plans were presented to former London mayor Boris Johnson in April 2016, but it is not known whether his successor, Sadiq Khan, is considering approval of the project.

Greening brownfield sites 

A derelict paper mill site in Otley, UK, is being regenerated with the development of a new hydroelectric turbine, which will generate electricity from the adjacent river weir to offset the carbon emissions. Two 10-metre Archimedes screws have now been installed at the West Yorkshire site, which will function by allowing water from the weir to pass through the top of the screw, with the weight of the water pushing on and forcing downwards in a helical flight. The water will then fall to the lower level, causing the screw to rotate. An electrical generator connected to the main shaft of the screw will extract the rotational energy. 

The two screws are each the length of a single-decker bus and almost twice as wide. They are expected to generate up to 1,300MWh per annum, making the site carbon neutral. Other environmental initiatives at the same site include an otter holt, bat chamber and a fish pass to help protect local wildlife.

Bendable concrete could ramp up construction 

Scientists from Nanyang Technological University (NTU), Singapore, have developed a new type of bendable concrete they claim could speed up construction times and reduce maintenance. The ConFlexPave contains polymer microfibres that are thinner than a human hair to allow the concrete to flex and bend under tension, while also enhancing its skid resistance.

Professor Chu Jian, Interim Co-Director at NTU, commented, ‘We developed a new type of concrete that can greatly reduce the thickness and weight of pre-cast pavement slabs, enabling speedy plug-and-play installation, where new concrete slabs prepared off-site can easily replace worn out ones.’

Typical concrete comprises cement, water, gravel and sand and can be prone to cracks if too much weight is applied. By adding the microfibres, the group was able to achieve a bendable, stronger and more durable mixture than regular concrete. 

According to the team, understanding how the components of the materials interact with one another mechanically on a microscopic level led to the discovery. ‘We can then deliberately select ingredients and engineer the tailoring of components, so our final material can fulfil specific requirements needed for road and pavement applications,’ explained Professor Yang En-Hua, who led the study. 

‘The hard materials give a non-slip surface texture, while the microfibres distribute the load across the whole slab, resulting in a concrete that is tough as metal and at least twice as strong as conventional concrete under bending.’ 

The ConFlexPave can be pre-cast in slabs for quick installation. Having tested it in the lab, using tablet-sized pieces, the team now plans to install full-sized slabs around the University to test pedestrian and vehicular traffic in the next three years.