To support the construction of the major new Doha water infrastructure project in Qatar, known as Messaimeer RPS and associated pipelines, Qatar Building Company has used a range of formwork and shoring solutions from RMD Kwikform to cast slabs on four large concrete reservoirs.
As an extension to the existing GTC299 city infrastructure programme, the Messaimeer RPS and associated pipelines, incorporated the construction of four circular concrete reservoirs, eight metres high and each with a diameter of 125 metres.
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 to fulfil the customer needs. The RMD Kwikform Qatar based design team, worked with QBC engineers to design the solution for both Alshor Plus and Rapidshor tables, ensuring the Superslim and GTX decking 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 decking to be reused across all four reservoirs.
Commenting on the challenges of the project, the QBC project manager said: “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.
“Having worked with RMD Kwikform for over 5 years and 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 7.5 metre 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.”
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 7.5 metres. The slab formwork was designed to incorporate the casting of 418mm thick, 3 metre by 3 metre column pads. These were then cast at the same time as the main 2.5 metre thick 1.25 metre diameter main slab.
In total, there were up to 550 tables used to construct the slab. The majority of these tables were made up of six legs, braced with frames, to create a table measuring 6.3 metres long, 3.6 metres wide and up to 7.5 metres high. Once each table was erected and fixed into the right location, the 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, allowing for a table drop of 12mm. The 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 also 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.
Commenting on the project Izzet Ataol, sales manager for RMD Kwikform said: “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. 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.”