Guaranteeing Qatar with a steady supply of clean water for its population is proving fertile ground for formwork specialist RMD Kwikform as the Gulf state rolls out a series of desalination plants and reservoirs.
Providing drinking water to the people of Qatar is a challenge. Demand is high, it’s hot, living standards are good, and water bills - as with all bills and taxes in the Gulf - are kept low, so there is little restraint on consumption.
There is no watercourse anywhere in Qatar and the groundwater is aggressive and not potable. So the nation relies on desalination plants, which in turn rely on power supplies, which can, in turn, be vulnerable.
In short, it needs back up. And it is getting it through a massive QR10bn (£1.7bn) investment from Qatari government.
Last year power and water company Kahramaa awarded Hyder a £16.8M contract to design a series of massive reservoirs to store treated water from the country’s desalination plants and project manage their construction (NCE 5 April 2012).
“This project is absolutely fundamental to the future of Qatar,” Hyder head of utilities Neil Kemble told NCE last year. “At the moment there is some storage, but not a lot. This project is designed to give resilience in the same way that in the UK we have natural reservoirs.
To get that level of storage is an immense undertaking, demanding huge civils structures.
We had four months to get the job done and we knew we needed to source a significant amount of equipment
Barry Elliot, QBC
There are 31 reservoirs spread across five sites, each measuring up to 1km2.
A total of 1M.m3 of concrete will be needed across the five sites. On the case on one of them - Messaimeer - is RMD Kwikform. There, contractor Qatar Building Company has used a range of formwork and shoring solutions to cast slabs on four such reservoirs.
Each is 8m high and has a diameter of 125m.
Having worked with RMD Kwikform on similar slab projects, Qatar Building Company (QBC) specified a combination of Alshor Plus and Rapidshor shoring tables, with Superslim Soldiers and GTX timber beam supported formwork. This equipment was used to complete the slab construction simultaneously on all four reservoirs, with the table form approach reducing cycle times by up to 50% compared to standard use.
With a tight programme of just four months to complete the slab construction, RMD Kwikform sourced product from across its Middle East businesses, storing it in its Qatar depot. The Qatar-based design team, worked with QBC engineers to design the solution for Alshor Plus and Rapidshor tables, ensuring the Superslim and GTX formwork panels could be used across both systems.
This approach eliminated the need for additional work and by standardising the panels, allowed QBC to assemble just four different variants onsite. In-turn this reduced the need for additional works and allowed panels to be reused across all four reservoirs.
“For this project it was all about time and scale. We had four months to get the job done and we knew we needed to source a significant amount of equipment, get it to site swiftly, erect it and get it offsite efficiently, once the job was completed,” says QBC construction manager Barry Elliot.
“Having worked with RMD Kwikform for over five years and more recently on a similar reservoir project, we knew they could design a solution to meet our needs.
Having previously used Alshor Plus in particular, we knew our site staff would also be familiar with the product and therefore faster in the erection and dismantling processes.
“Due to the simultaneous nature of the project and the amount of equipment needed, we opted for a combination of Alshor Plus for the first two slabs and Rapidshor shoring for the second set, with interchangeable slab formwork. For both solutions we opted for a table approach, erecting Alshor Plus and Rapidshor into 7.5m high table sets, that could be struck and moved on special castor units to the next slab section. This reduced the need for erection and dismantling, cutting up to 50% off the time from one pour to the next.
We were all confident with the solution and equipment. The main challenge, however, was the huge amount of equipment needed for the job
Izzet Ataol, RMD Kwikform
With internal columns already cast to support the main soffit slab, the team onsite constructed Alshor Plus and Rapidshor tables to support a slab height of 7.5m.
The slab formwork was designed to incorporate the casting of 418mm thick, 3m by 3m column pads. These were then cast at the same time as the main 2.5m thick 1.25m diameter main slab.
In total, 550 tables were used to construct the slab. The majority of these tables were made up of six legs, braced with frames, to create a table measuring 6.3m long, 3.6m wide and up to 7.5m high. Once each table was erected and fixed into the right location, the formwork panels were lowered into place and fixed using U head connectors.
To support the striking process, long jacks with standard quick strike mechanisms were used at the base of each table, allowing for a table drop of 12mm. The site team then used the Alshor Plus castor units to move tables into the next pour position.
The sequencing of the slab construction started in the centre of the structure, with tables then moved accordingly to support the completion of the slab. The tables were then dismantled using a specially designed access system.
In addition, to design support and equipment delivery, RMD Kwikform provided site services personnel, who were used to assist the teams on the erection and movement of the tables, to ensure this was completed safely.
“Having previously worked with QBC on a similar job to this, we were all confident with the solution and equipment.
The main challenge, however, was the huge amount of equipment needed for the job,” says RMD Kwikform sales manager Izzet Ataol.
“Logistically we had to work very quickly to co-ordinate the delivery of equipment. We then liaised with the QBC team to ensure we delivered the right amount of equipment to site, when it was needed.”