Site visit: Lusail CP5B road project
Samsung C&T is nearing completion on an infrastructure project covering main roads and utility connections for a busy section of the $50bn Lusail City project.
As contractor Samsung C&T approaches the end of a three and-a-half year programme to install infrastructure that will provide the main routes around Lusail City’s residential communities, project manager Tae Hwan Cho and construction manager Ki Young Jeong admit that it has not been without its challenges.
The fairly tight timeframe is just one part of the story; the tough conditions and the logistics of working in a district where there are scores of other contractors trying to build other things including offices, residential projects and even a new Light Rail System have also added complexity to the job.
The contract package, CP5B, was started on site in mid-January 2012 and is due for completion by the end of June. It involves the construction of four major roads, with two underpasses, as well as all utility tunnels and connections. In total, there is around 11.4km of roads that have been built around a 38km2 (3,800 hectare) site some 22km north of the centre of Doha.
The roads both encircle and dissect the huge, $4.9bn Golf City district planned for the $50bn Lusail City project launched by Barwa Real Estate at Cityscape Qatar in 2012 – initially as a joint venture but now being wholly developed by the firm.
It also services a northern residential district (5A), the main waterfront district linking to Qetaifan Island (where Samsung C&T has also installed interconnecting bridges under contract package 3A), the Fox Hills North residential project, and the northern parts of Lusail’s Energy City and the Education District.
Samsung C&T was appointed by the client, Qatari Diar-owned Lusail Real Estate Development Co (LREDC), under a contract that was initially worth $259m. However, once variation orders are taken into account, the final sum is likely to be around $353.8m.
Although the project was split into five sections, it largely consists of two different types of work. The first is the major roads, including the eight-lane highway running from a nearby motorway which will provide the main access road into Lusail City. The second is the accompanying service roads connecting this to the developments.
“Regarding the major roads, we have already completed them,” project director Tae Hwan Cho tells Construction Week. “With certain small parts excepted, the major roads are already done. The main part now is the services roads and they will be completed by the end of June,” he confirms.
Alongside the 11.4km of roads, though, there are also two major underpasses – one that is 1km long and the other 500m – as well as around 2.4km of utility tunnels. These contain potable water, sewage and an irrigation pipe network, as well as electrical cables linking five site substations, gas piping, electrical and telecoms (Qtel) ducts and wiring, district cooling and other MEP equipment including mechanical fans and traffic light sets for 16 different road junctions.
The utilities tunnels were built alongside the underpass sections and were also divided into two sections – a ‘wet’ utilities chamber containing the sewage and potable water pipes and then a ‘dry’ section with the electrical and telecoms networks. In total, the tunnels contain 176km of ducts, pipes and cables.
The stormwater drain was housed separately, running alongside the roads as it relies on gravity to pick up water accumulated in the drains (which are also used by neighbouring residential communities) and bring it down to the lowest part of the site near the coast.
“Because of that, from the starting point it is shallow but at the end it will be very deep,” explains construction manager Ki Young Jeong. “At the starting point, it is 800mm in diameter but at the end it will be 2,200mm.”
Indeed, the difference in height from the top of the site to the bottom of the deepest underpass is around 17m. Jeong says it had to work from either end of the site from the outset, and in particular to address the deepest points first.
Jeong adds that ground conditions in Qatar meant that this proved to be a challenge, particularly as some of the deeper sections were closer to the sea.
“If we go deeper and deeper, the soil is worse because this is limestone. Limestone can be easily weakened by the salt water and dissolve, so there can be cavities in there,” he says.
“So the ground is very hard but underneath is very loose. You can find big cavities and because of that we had difficulties when dewatering.”
In order to keep the site dry, Samsung C&T had to install a deep well watering system, with holes drilled into the ground and huge pumps used to extract water. Yeong explains that the extracted water is then pumped into a 100m-wide sedimentation pond, where it is allowed to settle. Once this takes place, the clean water is discharged back into the sea.
He says there were a number of contractors working on neighbouring sites including CDC, Al Jaber Engineering, Al Akharia Trading & Contracting and Spain’s FCC, and that there had been some initial issues around things like access and road use.
As a result, the group has since held regular interface meetings, which he says has helped to resolve potential problems quickly before they have a chance to develop.
Other challenges have included the climate, which was extremely hot during the summer months, with a summer working ban preventing outside work taking place from mid-June to September each year between 11.30am and 3pm.
Cho adds that logisitics has been another area that needed to be addressed to make sure all goods and equipment arrived on time. Items with a long lead time for delivery, such as some of the MEP equipment like SCADA systems and monitoring systems received the most attention, with delivery times being checked well in advance.
Samsung C&T also deployed an in-house procurement organisation where its regional base in the UAE liased with offices in source countries to make sure products would arrive on time.
Sourcing building materials within Qatar was also tricky, and it had to contend with a country-wide shortage of washed sand at one stage. But Jeong said that it put strategies in place to mitigate this wherever possible, including the use of several concrete suppliers.
“In general, we just use the one supplier because if we give them the work we will get a cheaper price. But here, we know the logistics and it is very difficult to get concrete,” he says.
For instance, when CW visited the site in February, the contractor was using three different suppliers, although Jeong explains that at peak it had been using as many as five.
Cho adds that the peak for the project took place in the latter half of 2013, between September and December, when all parts of the site were active. At that time, it had around 4,500 workers on site and was using 500 different pieces of machinery. Currently, the number of workers has dropped back to around 2,500 as the completion rate at 26 April reached 91.6%.
It has also sought to accelerate certain aspects of construction in order to meet the deadline. For instance, in the underpasses, wall heights average around 14m and are 22.5m wide. Constructing this piece-by-piece on site using traditional methods would have taken a long time, so a subcontractor has prepared huge rebar cages that can be built on one part of the site and dropped into place.
Jeong says that it fabricated a device to allow these massive rebar cages to be more easily handled and manouevred into position using cranes.
“Because if we just lifted the rebar after assembly it would be bent. The critical moment is when you lift it. After you lift, it will be fine.”
Cho adds that another unusual shortcut was taken in using precast sections for huge manholes for the stormwater drain. Precast is typically used for light and medium-weight manhole sections, as heavier ones weigh up to 40 tons. However, Samsung C&T had a 400-tonne crane on site to make sure they could be properly handled.
Finally, the firm says that health and safety has been a major priority, and that it imported a special training centre from its Korean HQ that uses all manner of gadgets from air-lines to trapdoors and collapsible platforms to show the importance of wearing PPE and proper methods of handling electricity, scaffolding and working at height.
The centre, which has won praise from LREDC, offers workers arriving on site a “basic awareness” of codes to follow.
“Obviously, it’s not a full-fledged training programme, but it makes them aware of the hazards,” says health and safety manager John Murphy. “We’ve put about 7,000 people through our safety training programme.”
Lusail CP5B in numbers
rebar 44,662 (tons)
Foul sewer 5,257m
Potable water 14,579m
66kv (HV) cable 6,536m
11kv (MV) cable 39,800m
LV cable 9,078m
ELV duct 22,293m
Qtel duct 24,547m
underpass lighting 1,443
traffic signals 16 sets
District cooling pipe 3,330m
Drainage sump pump 138
gas network 11,536m