Qatar’s Public Works Authority (Ashghal) has invited companies to express interest in the construction contracts on its estimated $12bn Sharq Crossing scheme.

The 12-kilometre-long crossing, which was officially launched in December 2013, is one of the biggest infrastructure schemes planned in Qatar. It involves building three bridges interconnected by subsea tunnels across Doha Bay, which, when completed, will link Doha’s new Hamad International airport with the city’s cultural district of Katara and the central business area of West Bay.

The works will be split into eight packages:

1. Land-based enabling works contract
2. Marine-based enabling works contract
3. West Bay approach and bridge contract
4. Cultural City approach and bridge contract
5. Sharq approach and bridge contract
6. Immersed tunnel and marine interchange contract
7. Surface street modifications contract
8. Systems integration contract

There will also be an operations and maintenance contract.

The most significant packages are the design and build contracts covering the West Bay approach and bridge, the Cultural City approach and bridge, the Sharq approach and bridge, and the immersed tunnel and marine interchange contract.

It is understood the bridges, which will be between 600 metres and 1,310 metres in length, are steel deck bridges and will be attractive to contractors from South Korea.

Ashghal still has to hire a consultant to finalise the packages and prepare the tender documents. That role will involve working closely with Spanish architect Santiago Calatrava, which prepared the concept designs for the bridges.

The authority has appointed US-based Fluor Corporation as the programme management consultant to supervise the construction.

Work on the project is expected to be completed before the Fifa World Cup in 2022.