RMD KWIKFORM IBÉRICA GOES UNDER IN SPAIN AND OVER IN PORTUGAL WITH TWO DISTINCT PROJECTS
For RMD Kwikform Ibérica, spanning the gap from Spain to Portugal is one of many challenges the formwork and falsework specialist has overcome, thanks to its expertise in delivering solutions for complex bridge and viaduct projects throughout the region.
Given the dual challenge of engineering a formwork and falsework design for the construction of the Ferreras Viaduct in Asturias, Spain and the Bridge over the river Homem in Braga, Portugal, the expertise and innovation of the design team at RMD Kwikform Ibérica was certainly put to the test.
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.
The first of the two projects to be 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 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.
RMD Kwikform Ibérica technical director, Santiago Palmero: “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. 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.
“Once the viaduct was formed, in order to facilitate the removal of the falsework, we supplied hydraulic cylinders capable of withstanding 250Tm with step strokes of 25cm. These cylinders were placed in between the beams that went through the piers and the transversal HEB-800 beams that acted as support for the girders,” added Santiago.
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.
Santiago: “Once we were able to combat any girder deflection, we completed the design of the interior of the box shape using a combination of SuperSlim and T200 beams. This allowed concrete to be poured for the first phase of the viaduct construction, which covered the bottom soffit and stems. Panel formwork, made up of steel panels mounted on special beams and turnbuckles, were then used to form the base for the second phase pour, which formed the top soffit.”
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 safe access to key parts of the system, allowing them to be monitored and measurements to be confirmed. With the final pour completed and equipment now removed from site, the successful on-time construction of the Ferreras Viaduct has enabled work to progress on the remainder of the A8 motorway project, with some sections already open to traffic.
Whilst RMD Kwikform Ibérica staff were busy working with colleagues at UTE Ballota to complete the Ferreras Viaduct Project, across the border in the Braga region of Portugal, engineers were helping to design the complex and eye catching formwork system used to construct the bridge to cross the river Homem.
Part funded by the European Union the construction of the bridge represents a significant step towards the completion of the regions road network and economic growth strategy, as it links the Municipal of Vila Verde with the City of Terras de Bouro, forming part of a route that will later link to the Ponte de Lima and the highway Porto / Valencia.
Constructed by Portuguese construction and public works specialist Sá Machado and jointly funded by Câmara Municipal de Vila Verde and Câmara Municipal de Terras de Bouro the 25 month, 2.4m euro project began in February 2006.
Due to the steep inclines and nature of the river valley, which was situated in a very rocky and mountainous area, in order to construct the bridge, a robust yet flexible system of formwork and falsework had to be designed to closely follow the contours of the terrain. This involved the use of a number of steel shoring, beam and girder products from RMD Kwikform Ibérica’s comprehensive equipment range. These included Superslim Soldier and standard steel beams, H33 girders, Megashor and Kwikstage shoring.
Spanning 130m, with a bridge elevation of some 40m from the centre of the valley, the height of the structure alone was a challenge for the team of engineers working on the project. As an extra dimension to consider, the preparation of the site was severely restricted due to its location in an environmentally protected area.
Santiago: “Often when clients talk about environmental challenges they more often than not relate to the impact of changing and extreme weather conditions. With this project not only did we have to contend with these issues, we were also faced with working on ground that could not be properly prepared, as the environmental protection given to the site eliminated the felling of trees or excavating. This therefore had a major impact on heavy crane access, which was not permitted. The levels of the river and nature of its path also meant that equipment could not be floated into place. This created a real challenge for our design engineers and Sa Machado’s erection teams, as there was a restriction on the weight of equipment that could be moved at any one time.”
With weight restrictions and limited crane access, RMD Kwikform Ibérica had to work closely with the Sa Machado team to utilise the strength and versatility of its Kwikstage shoring product, in order to design a system that could be easily erected, whilst providing the structural integrity needed to support the main bridge slab and sloping piles.
Santiago: “In order to support the client’s formwork for the sloping piles, we mounted a Kwikstage shoring structure onto a span of H33 girders. As a modular system, its versatility allowed us to work efficiently with the varying heights required to achieve the overall design. With a significant amount of Kwikstage shoring used within the design, its high leg capacity allowed us to combine other components within our portfolio to achieve the significant height requirements which ranged up to 40m.
“Constructed in phases the overall formwork and falsework design was secured to the base of the valley using H33 girders, which were positioned horizontally using jacks mounted on a small concrete base. Building up from the girders to achieve the required height for phase one, Kwikstage shoring was mounted and fixed to the H33 girders using adjustable base jacks. Once work on the abutment was completed, equipment including steel beams, girders and Superslim Soldiers was then used to create a platform from the abutment to the pile on each side of the valley.
“It was at this stage that our design challenge had to incorporate some specially fabricated formwork that the customer already had within its portfolio. Making the link between our equipment and the customers steel supports was made simple thanks to the flexibility of our Superslim steel beams, which are manufactured in nine different lengths from 10mm to 3600mm, and come complete with standard fixtures and clamps, to make the fabrication of virtually any length of support simple and effective.
“From a practical point of view the fact that formwork ties and other components can be fixed virtually anywhere along the length of a Superslim soldier gives our engineers the freedom to work within tight tolerances and site challenges, allowing them to optimise their design for the application at hand. In relation to the bridge design we were able to work with the very varied slope and rock formations of the valley to design a formwork system that was robust enough to cope with the required loads that could be dissipated into the valley walls, whilst having little impact on the overall remedial work required.”
Once the erection team had completed the second phase of the design to construct the formwork from the abutment to the pile on each side of the valley, Megashor towers were constructed to allow H33 girders to be fixed on top for the next elevation. Santiago: “Again, unlike other bridge designs, due to the restricted access issues we had to design alternative solutions to support the overall construction. Here we used a combination of Megashor towers, steel beams and Kwikstage shoring to provide the necessary support and structural integrity required for safe construction.”
Following the completion of the two main abutments, the main span of the bridge was erected using a number of H33 girders fixed together to create a central girder support some 24m long, over the river. Santiago: “In order to move the central girders into place, we had to overcome one very large hurdle, the fact that we could not bring in heavy cranes to lower them into place.
“This is where the RMD Kwikform engineering team came into its own, designing a specialist auxiliary scaffolding structure, which would allow us to erect the girders. With the surrounding conditions and elevation making moving the individual girders quite unstable, in order to make this process as simple and safe as possible, we positioned each girder into place one by one. Once the central span of girders was completed Kwikstage shoring was erected on top to a height of up to 20m in order to support the formwork that would then give the bridge its definitive and distinctive form.”
Santiago concluded: “When it comes to bridge and viaduct design making the simple into the iconic is what we are all about. Whether it is the challenge of tight deadlines, restrictions placed on work by environmental need or the remoteness of a location, each project we work on receives its own special engineering and design effort, particularly in this case, as both jobs had very different but exacting needs. As a business it is by taking this approach that we can play to our strengths, experience and product range, that allows us to provide equipment and designs that not only meet our customer needs but exceeded their expectations.”