After months of nominations from top industry figures and frantic voting in our online poll, you have chosen computer aided design and computer aided manufacture to take the joint title of being the greatest advance in construction. Alexandra Wynne talks to industry experts on why they champion the age of the computer.
Six months ago, Construction News along with sister titles Architects Journal and New Civil Engineer, in association with Corus Advance, embarked on the ambitious campaign to find out what is the all-time greatest advance in the construction world.
It was a big challenge, so the magazines invited key industry figures to put forward an impassioned plea for their nominations. What followed was a flood of suggestions ranging from the familiar (Olympic Delivery Authority chairman John Armitt’s plug for reinforced concrete for one) to the somewhat obscure (Grand Designs presenter Kevin McCloud plumped for silicone sealant).
The final short-listed ten has been subjected to months of online voting. But the public has spoken and computer aided design (CAD) with its partner in construction computer aided manufacture (CAM), has taken the top spot.
“That CAD/CAM is such a clear favourite indicates that architects and engineers recognise the value of technology to help them achieve the aims of a modern and increasingly efficient construction industry,” says Corus Construction marketing manager Roger Steeper.
“The whole process of steel construction, from manufacture, through fabrication to erection, fits perfectly with these new and improving technologies.”
In an era obsessed with bigger and better it is easy to see why three-dimensional (3D) design software is so popular in designing glamorous bridges, roofs, stadia, tall buildings and more.
“The obvious benefit of CAD is that we’re more able to build structures with a more complex geometry than before,” says fabricator Watson Steel design director Iain Hill. “Architects are more prepared to go for more advanced designs now and increasingly more complex structures are being attempted.”
He adds that it might have been possible to attempt these complex geometrical designs before, but the birth of CAD has given designers the confidence to be able to see them through.
In recent years, there have been countless examples of grand designs. From the intricately woven mass of steel at the Bird’s Nest Stadium, which ensured it became one of the biggest winners at last year’s Beijing Olympics, to the ever more challenging attempts by major cities to host the tallest, most attention seeking skyscrapers.
London’s geometrical cigar-like skyscraper at 30 St Mary Axe (more familiarly known as The Gherkin) and Dubai’s the sail-like frontage of the Burj Al-Arab in Dubai may be two of the more famous benefactors of CAD and CAM.
Meanwhile the London 2012 Aquatics centre with its S-shaped roof along with the World Trade Center’s Freedom Tower are both under-construction projects that most likely promise to become beacons of computer aided success. Even Paris – not typically associated with tall buildings – looks set to get its own CAD/CAM influenced skyscrapers as plans were unveiled last month for interlocking twin towers that will be triangular in plan.
The principal way CAD enables all of this, according to architect Make founder and partner Ken Shuttleworth, is because of the variety of perspectives it gives, which was previously impossible with drawings on paper or cardboard models.
“Without question it has made the biggest difference to how we work,” he says. “And it has allowed buildings to be more flamboyant because it produces a single 3D model that you can chop into to get different sections throughout the building,” he says.
Rather than simply encouraging convoluted structural visions to be explored, the experts also laud the success of CAD and CAM in improving the design process.
Structures expert and Atkins practice manager Charles Johnson says: “Any unusually shaped building is difficult to visualise and draw without CAD. It’s definitely allowed us to take a big step forward and has added to the accuracy of what we do.”
Shuttleworth and Hill both say that there have been a lot less errors since people began relying on computers. “We don’t get anywhere near as many nasty surprises on site anymore,” says Shuttleworth.
Hill attributes this to the built-in clash detection checks, which mean the design team knows what is going to happen with the structure in a 3D environment before it even gets built.
Johnson adds: “In the old days we were stuck with paper. It is now easier to identify clashes that cause a lot of trouble on site – now they can be dealt with in the design office.”
To illustrate, Hill says: “Imagine you need a steelwork beam to connect to a steel column with bolts. Before CAD, you would likely have a draughtsman drawing the column and another draughtsman working separately on the beam.
“In the end you could very likely find out that one has drawn a different bolt arrangement from the other and they column and beam won’t fit together on site. That error just doesn’t exist anymore. There could still be other errors, but we know it will at least fit together.”
Shuttleworth says he wished it had been possible to use CAD when he worked on the Hong Kong and Shanghai Bank (HSBC building) in the 1980s. Tolerance levels were at +/-40mm compared to much higher levels of accuracy on the Gherkin. “The brackets and frame – everything was dead centre and dead accurate [on the Gherkin],” he says. “No tolerance was used whatsoever.”
As well as eradicating errors and improving accuracy, CAD is being name-checked in the fight for sustainability. Greater accuracy means less waste of materials.
“For structural engineers one of the biggest benefits is the ability to make steel frames much lighter [leading to less steel being used], because every force in every member can be analysed,” says Shuttleworth.
The experts quickly dismiss the critics who challenge the trend of designing to impress with geometrical wizardry and lament the loss of the old workman’s tools of chalk, pencils, tape measures and drawing boards?
“It’s really old fashioned and dismissive to say the craft is lost,” says Shuttleworth. “People can now craft things with a mouse in the way you might with a pencil.
“Plus there’s an amazing crossover now between the different disciplines of architecture, filmmaking, graphic design and art. So many people working in our firm have experience in the film industry. It’s opening up the industry like never before.”
Hill says fabricators are more than capable of adapting to change. “The process now is less labour intensive. It used to be guys on the shop floor measuring with chalk and a tape measure. Those guys are now more familiar with computer controlled drawings and they have total workstations that are effectively like an electronic theodolite.”
CAD/CAM has paved the way for more changes to building in the future – something that has started with the evolution of building information modelling and will likely continue with more innovations in software and technology.
The experts put forward their CAD successes
Ken Shuttleworth: St Paul’s Cathedral information centre
“It’s a little kiosk outside the cathedral but its success was being designed using very complicated 3D drawings.”
Charles Johnson: Dubai Metro stations
“There were a lot of very complex steel canopies above the stations, which to build would have been a very tedious process without CAD. It could have been done by hand but the time we’d have had to spend on the project before would have been enormous.”
Ian Hill: Emirates Stadium roof
“Yes, we could have built it without CAD but that would have meant a greater potential for errors. And this way it was much quicker.”