RMD Kwikform Ibérica uses the flagship shoring system Megashor for two innovative projects
For RMD Kwikform Ibérica, making a conference call whilst in a viaduct is commonplace, thanks to the combination of its latest two projects, designing formwork and falsework solutions to simultaneously construct the Princess Letizia Congress Centre and Ferreras Viaduct in Asturias, Spain.
The two distinctively different projects have one thing in common, as the solutions designed to support their construction have both relied on the use of components from RMD Kwikform Ibérica’s flagship Megashor heavy duty shoring system and beam ranges.
Designed by the famous architect Santiago Calatrava, the contract for the construction of the Princess Letizia Congress Centre was awarded to Spanish construction firm UTE Buenavista in June 2003. UTE Buenavista then selected RMD Kwikform Ibérica to design the unique shoring system required to provide support for a key element of the construction phase. Made up of two main buildings, housing an exhibition and congress centre, council offices, a hotel and shopping centre, it was the landmark oval shaped main congress centre, with its mobile roof, constructed with no fewer than 31 white steel ‘ribs’, that provided the falsework challenge for RMD Kwikform Ibérica.
In order to safely construct the roof sections, a strong and flexible propping system was designed to allow 23 of the 31 steel ‘ribs’ to be manoeuvred via crane and remotely secured in the relevant position within the structure. Each of the specially fabricated ‘ribs’ were individually supported by Megashor towers, designed to provide a secure and accurate platform for the whole roof structure to take shape.
Precision design engineering was required to develop a solution that met the exacting required angles of placement and support for the transmitted forces attributed by each ‘rib’, which varied dramatically from 31Tm to 91Tm. It was the scale of these forces and the restrictive nature of the design, that created the major challenge for RMD Kwikform Ibérica engineers, as Technical Director, Santiago Palmero explained: “The solution we had to provide was restricted by two main issues; the first was the maximum footprint the Megashor towers could have on the ground, as we needed to be able to lift them out of the roof structure after it was completed, without damaging a ‘rib’. This footprint turned out to be less than 1.4m across to allow a crane to lift out the entire tower.”
“The second issue related to the positioning of the Megashor towers, which had to be placed directly above the pillars that were constructed in the lower levels of the complex, on a grid measuring 8.25m x 8.25m. With each of the Megashor towers weighing a number of tonnes, this was extremely important, as we had to make sure we had adequate support for their weight. Using all of these parameters and understanding the capabilities of Megashor, which is able to support axial loads of 1,000kN/m2, we devised a solution involving Megashor towers of dimensions 2.986m x 1.010m, placed at 8.25m intervals.”
Completing the design, a special jig, beam and girder system was mounted onto the towers, with RMD Kwikform Ibérica beams of 9.0m and 12.0m in length, complementing the use of girders from UTE Buenavista for those axes where loads were greater.
Santiago continued: “To complete the design, we erected a secondary level of shoring and brackets on top of the jigs, that held the “ribs” directly. Taking this approach, we were able to make sure the system could support the ‘ribs’ and manoeuvre them into the precise location required.
With the final ‘rib’ now fixed in place and the Megashor towers removed, a key part of the construction of the Princess Letizia Congress Centre has been completed, leaving the remainder of the five-year development on course to be finished by August 2008.
Not far from the Princess Letizia Congress Centre, already squared off and recently opened for use, is the box shaped Ferreras Viaduct, constructed by UTE Ballota, a joint venture between Spanish construction firms Aldesa, Tapusa and Dicaminos.
Situated on the Ballota-Cadavedo section of the A8 motorway widening scheme, the Ferreras Viaduct was constructed using an integrated formwork solution, comprising a range of RMD Kwikform Ibérica equipment, including Megashor shoring, R700 girders and specially fabricated HEB 800 beams.
Based around a design incorporating gantry style falsework, the major challenge to this project was the development of a solution that did not require the use of intermediate supports, due to ground preparation issues. Measuring 11.5m in width, the formwork and falsework solution was designed using interior formwork and split into five spans of lengths between an axis of 25.5m-28.5m-31.5m- 28.5m-25.5m. In total the length of the viaduct between stop ends was 141.3m, with the maximum height of the bridge approximately 30m.
“The fact that we couldn’t use intermediate supports for this project, meant we had to take a totally different view of the challenge we faced,” explained Santiago. In order to overcome the obstacles, we took an innovative approach to supporting the construction of the five different spans, using complete spans of R700 girders, supported by a row of Megashor feet on the foundations of the abutments. We then incorporated specialist transversal HEB-800 beams, reinforced with triple webs into the design. The HEB-800 beams loaded onto beams that went through the piers in their upper part. This was made possible thanks to windows in the structure that the client prepared, enabling equipment to be adequately sited.”
Due to the complex nature of the angles and fixings involved within the design, in order to adapt to the variation in longitudinal and transversal slopes and to correct the deflections of the girders, RMD Kwikform Ibérica developed a system of double Superslim Soldier beams in the base of the formwork. Special parts were then fabricated to connect Slimshor bases to the beams to allow adjustments to be made according to girder deflections.
With a complex design requiring various adjustments at different stages in the project, in order to ensure the highest levels of safety, RMD Kwikform Ibérica designed a complete access system, including stairs and brackets that was made up of Superslim and T200 beams, anchored to the piers. This allowed complete
Santiago concluded: “Each of these projects required a major engineering and design effort, as both had very different but exacting needs. By playing to our strengths, experience and product range, we were able to provide equipment and designs that not only met our customer needs but exceeded their expectations, further enhancing our reputation to deliver cost effective formwork and falsework solutions.”
