The pair, together with Asian investors, are reported to have bought the 22-24 Bishopsgate site for £220m and now plan to build a simplified tower design that will be the tallest in the city.
WSP has been signed up as the structural and building services consultant with architect PLP working on the design.
The firm was also structural engineer behind the Shard and New York’s Freedom Tower.
Contractor Brookfield Multiplex was forced to abandon construction of the Pinnacle tower in early 2012 after the core reached seven storeys when funding dried up.
The complex helter-skelter design, with customised curved curtain walling, will be dumped in favour of a streamlined, more cost-effective tower.
This will involve demolishing the existing concrete core, which led to the site being nicknamed The Stump, to clear the way for a fresh start.
Early working designs purporting to be for the new 60-storey tower have been released on the Skyscraper City internet forum, where they have been criticised for lacking the striking architectural presence of the previous Pinnacle scheme.
Plans will be submitted to the City Corporation planning authorities later this year with the aim of completing the new tower by 2018. The backers hope to start construction before the end of 2015.