Saudi Arabia’s General Authority of Civil Aviation (Gaca) expects the concept design for the SR2.2bn ($587m) renovation work at King Khalid International Airport in Riyadh to be completed by mid-September.

Construction work on the utility tunnel, to be located underneath the existing taxiway, is also expected to commence shortly after the concept design is completed and approved, according to a source with knowledge of the project.

Lebanese consultancy firm Dar al-Handasah is undertaking the project’s concept design.

Earlier this year, a joint venture of Turkey’s IC Ictas and the local Al-Rashid Trading & Contracting was awarded the SR2.2bn, four-year contract to redevelop the four existing terminals and the airside utilities at the airport.

The team lost its bid for the contract to upgrade the terminals in 2015 to a joint venture comprising Germany’s Hochtief, local Nahdat al-Emaar and India’s Shapoorji Pallonji.

The contract with the Hochtief-led team, however, was cancelled in 2016.

Unlike the cancelled contract, which calls for the construction of new concourses, the new contract entails mainly renovation and refurbishment works that aim to expand the terminals’ capacities and improve services.

The redevelopment of the airport will be conducted in phases, starting with the unused Terminal 4.

The next phase will involve renovations for Terminal 3, which has been closed since August last year. Terminal 3 used to cater to domestic flights, which have been moved to the newly completed Terminal 5.

The next phases will entail redevelopment work for terminals 1 and 2, which cater to international flights.

Terminal 5, which was completed in 2016, is being operated and managed by Dublin Airport Authority (DAA) under a five-year contract with the General Authority of Civil Aviation (Gaca). A joint venture of Turkey’s TAV and local Al-Arrab Contracting won the $430m contract to build the terminal, which has a capacity to handle up to 12 million passengers annually, in 2012.

A new terminal, Terminal 6, is now being planned. It will be developed using a build, operate, transfer (BOT) model.

The ongoing redevelopment of King Abdulaziz International is the first of a three-phased expansion plan meant to take the airport’s annual passenger capacity from the current 20 million, inclusive of Terminal 5, to 80 million by 2035. The three-phased project initially had a total budget of $28bn.

King Khaled International processed 23.7 million passengers in 2016, up 5 per cent compared to the previous year.