Engineers leading the design work on the new Daniel Libeskind building said that they had learnt the lessons from the 11 September disaster.
Steel diagrids and concrete encased steel framed lift cores are set to be key features of the reborn World Trade Center.
'The tower will have a concrete core with a steel perimeter. This is the case for WTC7 being rebuilt too, and is quite a big change of philosophy for New York buildings which were traditionally steelframed, ' said Arup principal in charge David Scott.
He said Arup had completed preliminary concept design and analysis work on the structure, such as lateral load analysis, and preliminary assessment of vibration and deflections. He countered some critics, saying that a 'cost-efficient and effective structure will be built'.
'We have done enough work to know the building will be efficient, cost-effective, robust and with plenty of redundancy, ' he said.