Ted Piepenbrock, head of Ove Arup & Partners’ earthquake engineering and advanced technology arm, said: “Turkish building codes are among the best in the world. The weak link was the implementation and enforcement of the regulations, and the responsibility for that lies with the municipal authorities.”
He added: “We shouldn’t blame contractors. They’re going to build to minimum standards. That’s the nature of contractors; it’s the nature of the game. I’m not trying to defend them but society must impose the standards.”
Piepenbrock, who returned from visiting Ove Arup’s Turkish office last week, said the main reason for the lack of enforcement was that local authority building inspection services had too few resources to keep pace with the increase in building.
He said that although corruption was a factor in the disaster, its role should not be overstated. “Corruption is everywhere, it’s just a bit more perhaps in Turkey. Academics in Turkey predicted that this would happen and were unpopular for saying so. Going after cowboy builders in a witch hunt won’t bring change.”
Piepenbrock said many building regulations had been ignored. Contractors had been allowed to “pancake” or “lollipop” two-storey buildings, increasing their height by adding storeys without official approval. “Regulations are not the first thing on a municipal authority’s agenda. They needed to build homes quickly for a rapidly expanding area,” he said.
In addition, many of these buildings were constructed as “soft storey”. This means the lower levels that sit directly on foundations often had stronger and heavier structures built on top, causing the lower part of the building to crumble when the tremors began. Piepenbrock noted that many older “hard-storey” buildings, notably ancient mosques, had withstood the impact.
He added that many of the new buildings lacked adequate steel reinforcement and many buildings had been constructed with the wrong type of steel. A number of the collapsed buildings were found to have been built using smooth instead of ribbed rebar. Ribbed rebar gives concrete greater strength and resistance to movement and cracking. It has been in use for more than 50 years.
Piepenbrock said there was evidence that most of the concrete used in recently constructed buildings was too weak as contractors had used unwashed sand from the sea shore that contained high levels of moisture.
Piepenbrock added that one of Ove Arup’s largest projects in Turkey, the Toyotasa car plant in Adapazari, was built on the earthquake’s fault line but suffered no structural damage and was scheduled to open for business this week. “It is on top of the epicentre and was unaffected by the earthquake,” he said.
Piepenbrock said Ove Arup was assessing the structural safety of nearby residential buildings without charge. He said the total bill for reconstruction could be £80bn.