From new metros in Riyadh and Doha to super sized sewers in Abu Dhabi and Bahrain and road tunnels and pipelines in Oman, the Middle East tunnelling sector is buoyant. And although it is busy now a lot more work is set to come. Cities around the region are all planning metros and using the third dimension will be critical as authorities seek to limit disruption above ground .
For some states mechanised tunnelling is a new proposition but success on schemes such as the metros in Cairo and Dubai and sewer project in Abu Dhabi are giving clients the confidence to bring in TBMs to deliver their infrastructure. Data from the Construction Intelligence Center and research by Tunnels shows that there are over USD 63bn of tunnelling projects currently underway in the region driven by oil and gas, water and transport. This figure includes the enormous USD 22bn Riyadh metro scheme, which involves the simultaneous construction of six new metro lines, to be undertaken by three consortia. The full extent of the tunnelling requirements on this project is yet to be revealed but in all there will be 175km of new light rail laid throughout the city. Major development contracts were awarded in mid 2013. Lines One and Two will be delivered by the BACS consortia consisting of US Bechtel, Saudi Arabia’s Almabani, Athens headquartered contractor Consolidated Contractors Company (CCC) and Germany’s Siemens. The overall contract value is approximately USD 10bn.
Line Three running over 40km will be delivered by the Ariyadh New Mobility Consortia which consists of two groups. The electrical and mechanical equipment for the driverless metro will be delivered by the Electrical Works Group (EWG), whose members are Spain’s Ansaldo STS and France’s Bombardier; and the systems infrastructure is being delivered by the Civil Work Group (CWG) consisting of Italy’s Salini- Impregilo, India’s Larsen & Toubro and Saudi Arabia’s Nesma. Lines Four, Five and Six are to be developed by the FAST consortia led by Spanish contractor FCC with South Korea’s Samsung, France’s Alstom, Strukton from The Netherlands, Freyssinet Saudi Arabia and engineering consultants Typsa from Spain and French firm Setec. The contract is worth USD 8.2bn.
FIRST AMONG EQUALS
But for now the biggest scheme under construction is undoubtedly the Qatari capital of Doha’s metro which has seen the procurement of 21 earth pressure balance tunnel boring machines from Germany’s Herrenknecht. Between them the machines will excavate 113km of the emirate’s soft ground made up of Simsina limestone, Rus Formation and shale, creating three new metro lines in the process. And this is just the first phase of the scheme with the lines being extended and a new blue line added by 2026.
For the Gulf these new metro schemes owe much to the local pioneer of light rail, the Dubai metro. The first 52km red line opened in September 2009 and the second, 23km green line opened in September 2011. The contractor consortium was led by Japan’s Obayashi Corporation, with Kajima Corporation, Mitsubishi Heavy Industries and Turkey’s Yapi Merkezi. Despite experiencing cost and time overruns the project remains a major achievement for a region with no previous experience of TBMs or light rail. Of the first 70km of light rail system, 13km were tunnelled using three 9.56m diameter Mitsubishi EPBMs over ten separate drives.
Plans for extensions of the metro were put on hold as Dubai weathered the financial storm battering its state owned development companies and affecting governmental infrastructure spending, however the award of the World Expo 2020 has given a renewed impetus to the project. France’s Systra with US Parsons International are currently doing preliminary engineering for a new line out to the Expo site, which is adjacent to Dubai’s new Al Maktoum International Airport.
STEP
More recently however tunnelling activity has been focussed in neighbouring Abu Dhabi, which along with plans for its own light rail system, is nearing the completion of its new sewer network. Known as the ‘strategic tunnel enhancement programme’ (STEP), it is designed to replace the existing pumped wastewater network with a new gravity sewer system. A total of six contracts were awarded including three for the main 41km sewer, two for the connection pipework and one for a new pumping station. Tunnelling was achieved using 8 TBMs on 5km bores delivered in three contracts.
Upon introducing the project to the market in 2008 the scheme attracted over 45 expressions of interest and this was narrowed down to a list of 15. In September 2009 Italy’s Impregilo became the first contract winner, securing the AED 891M (USD 243M) contract for package T02. Involving three major work shafts, three additional access shafts and a total of 15.5km of tunnelling this section formed the centrepiece of the sewer and ranges in depth from 43m at the north end at work shaft five (WS5) to 61.9m at the southernmost point work shaft seven (WS7).
The deepest section of the sewer was also awarded to Impregilo, this time in November 2010. The contract involved construction of work shafts eight and nine and a 9.7km bore between them. The deepest shaft, number nine goes down to 79.7m. This drive is slightly larger than T02 with a 6.98m external diameter providing space for a finished internal tube of 5.5m diameter.
Both of these contracts are now complete with the final section, known as T01, which was awarded to Samsung C&T Corporation in February 2011, due for completion at the end of 2014. It included construction of five work shafts, three access shafts and three major tunnel bores making up a total section length of 16.1km. "All 41km of deep tunnel have been excavated without a single incident – the last breakthrough was last October (2013)," says Robert Marshall, STEP programme manager for the US firm CH2MHill. "The two Zublin contracts (for link sewers) should be complete by mid 2015 – although we have been given an additional 3.1m internal diameter section of link sewer connecting Al Reem Island into the system, which will extend the completion of Contract LS-01 to the end of 2015. We have nine TBMs of varying sizes on the link sewers, so with the eight TBMs on the deep tunnel contracts, we have used a total of 17 TBMs on the job."
So successful has Abu Dhabi’s experience been that Qatar is also using a similar strategy for its own super sewer, better known as the Inner Doha Resewerage Implementation Strategy (IDRIS). Once again CH2MHill is programme manager for the 40km sewer and 70km of link sewers which will serve the south of Doha. Like Abu Dhabi the scheme will use a single major pump station to transfer flows and requires a new wastewater treatment works to treat the sewage. The project budget is in excess of QR 10bn (USD 2.7bn). The eight year project is set for completion in 2019 and to date several major firms have been prequalified for the main trunk sewer which like Abu Dhabi has been split into three packages.
According to data from the Construction Intelligence Centre Qatar has the largest volume of tunnelling underway in the region at the moment, mainly thanks to its metro. The overall tunnelling market is estimated at USD 27.9bn and according to CIC the forecast compound annual growth rate in construction to 2017 is eight per cent per annum. This is closely followed by Saudi Arabia, again strongly boosted by Riyadh’s metro. However other metros are getting underway which will see other markets gain in value. Amman (Jordan), Kuwait City, Baghdad (Iraq) and Tehran (Iran) and Jeddah (Saudi Arabia) are all planning metros and are expected to require large tunnelling elements.
With so many projects planned and several underway it is no wonder that the industry is excited about the regional opportunity. From microtunnelled link sewers to EPBs for new metros the market in the MIddle East remains busy.
