New bridges have 'positive impact' all over Abu Dhabi
ABU DHABI // They had to look good, they had to be safe, and people had to want to walk all over them.
That was the brief for architects who designed nine new pedestrian bridges in the capital - and on top of all that, the job had to be completed posthaste.
"After winning the contract, the real work started as the client was keen to erect the nine bridges as soon as possible," says Olga Buettner, the lead architect on the project and managing director of BueTTner Architects & Engineers.
BueTTner won the architectural contract in May of last year, while the contracting company Al Jaber won the engineering, procurement and construction contract.
Ms Buettner, a German who was trained as an engineer at the Technical University of Munich and whose experience in the Emirates includes working on the Dubai Metro project, says the bridges' appearance was a matter of fitting in rather than standing out.
The idea was to fit the bridges into the urban environment by using a particular palette- white and beige, Ms Buettner says.
"People should be encouraged to use the bridge through its appealing design," she says. "The bridge should be a vibrant addition and not loud in its design language."
After gathering input from Abu Dhabi Municipality, Abu Dhabi Police, the Department of Transport and the Abu Dhabi Urban Planning Council, and considering international standards, BueTTner chose a modular structure for the bridge.
It fell to Al Jaber, with the help of a specialised engineering firm, to assemble that structure.
Sohail Bou-Ismail, projects director at Al Jaber, says a modular bridge is based on set pieces, or modules, of specific dimensions that can fit any bridge span. "In that way, a redesign is avoided every time the bridge's span changes," he says. "The design also allowed us to manufacture the modules beforehand."
Safety, appearance, sustainability, financial aspects, local sourcing, and ease of use were among the many considerations.
"The key to addressing all these concerns is to never compromise on the architectural design and beauty of a structure," Ms Buettner says. "A heavy and industrial-looking steel truss gets a new appearance through our architecture."
The framework of the bridge, which spans more than 80 metres, was based on perforated, lightweight aluminium cladding attached to a steel truss.
"Pedestrian bridges all over the world are generally not famous for their designs," Ms Buettner says. "To keep just an industrial truss will not fit the modern and sophisticated urban concept of Abu Dhabi at all."
The entire construction, she says, looks lightweight and elegant while the aluminium has an unconventional and modern design.
The underlying challenge for BueTTner and Al Jaber was to complete the project as soon as possible.
BueTTner's design allowed a bridge to be erected overnight, and moved and reassembled elsewhere.
"We completed the structures quickly, without disturbing the flow of traffic," Ms Buettner says. "But we made sure that the aesthetics of the bridge were not sacrificed."
The curved cladding appears like a net, which gives the bridge a wider shape. It also gives a feeling of extra security when a pedestrian crosses the bridge which is six metres above fast-moving vehicles. The decorative cladding also provides shade for the pedestrians.
Rows of perforation reduce the wind load on the structure. The bridges have much less space to accumulate sand dust and will require considerably less maintenance, according to Ms Buettner.
The cladding was made from aluminium that was coated and can last for years without rusting.
"Aluminium itself is resistant to corrosion," Mr Bou-Ismail notes. "It's a durable material that can withstand the severe weather conditions in the country and ventilates the walkway and is comfortable for pedestrians."
The first new bridge opened in February, across from Mushrif Mall on Airport Road.
Six more had opened by the end of June: across Muroor Road near the main bus station; across Airport Road outside the Carrefour supermarket; across Mussaffah Road at Workers' Village and near Dalma Mall; and across the Abu Dhabi-Al Ain Road at Baniyas and opposite Abu Dhabi University.
A bridge at Bahia on the Abu Dhabi-Dubai motorway should be finished next week; and the last one in the set, at Al Shahama on the same motorway, should open by the end of this month.
"As architects based in Abu Dhabi we feel great to see the positive impact of the bridges all over the city," Ms Buettner says. "It feels like being 'at home' in Abu Dhabi."
Ms Buettner will be training her sights on Dubai next: last month, her company won a tender to build 13 pedestrian bridges there.