Manufacturing and construction of tensioned external covers of facilities and stadiums hosting sports events and concerts for domestic and international markets, on the basis of custom plans.
During the designing and construction of 21st century stadiums, beyond the local conditions and the demands of the local sports club, the spectators’ needs and convenience should also be taken into consideration. Not only national-, worldwide- or Olympic-level sporting events are hosted in most of the stadiums nowadays: these buildings provide venue for a number of recreational events as well, such as concerts, performances, shows etc. In case of a well-functioning, comfortable stadium, the shading of the auditorium seating, and the special covering of VIP and VVIP sections can turn a standard stadium or arena into an architectural attraction with exceptional impression. The combination of membrane roof and tensioned facade membrane cover results in a building with a particularly modern appearance.
The partial or full covering of a stadium or sports complex render the building capable of hosting planned events in adverse weather conditions as well, and the sight of the roof structure ensure a lively, natural impact with good ventilation.
Although the UEFA and FIFA regulations do not require the mandatory covering of stadium grandstands and grounds, almost every newly built or renovated stadium grandstand and field are covered to increase utilisation and the visual experience of the visitors/spectators.
Beyond the increase of visual experience and shading, it is recommended to cover the possibly largest area for acoustic considerations as well. The so-called membrane covers - tensioned shell-structured covers - manufactured by Graboplan mitigate noise effects of an auditorium seating during public gatherings, and reduce the levels of external environmental noises as well.
ADVANTAGES OF USING STADIUM MEMBRANE ROOFS
- provides a unique appearance to the building
- unconfined visual possibilities
- leaner supporting structures will suffice
- made of light-transmitting, UV-resistant material
- surface can be used for advertising
- reflective effect - less illumination required at night
- ensures good solar exposure
- cost-efficient, durable solution
STRUCTURE AND SHAPES
When establishing the roof structure of stadiums, typically 5-100,000 square metres of surface areas have to be covered (could be even more or less), where usually complex custom-designed steel structures or supporting structures of wire ropes should be built. For the best results, the large spans, the shape of the membrane covers (which provide the final shape of the building), and the location of the covered area (auditorium seating - fields) have to be managed simultaneously when the nature of the structure is determined.
The supporting structure of the membrane roof can have a so-called compressing-clamping ring design, where the upper external and the lower compressing rings are connected to the inner clamping ring through upper and lower radial cables. In this case, the membrane usually has an arched shape. The arch is determined by the height of the supports between the two radial cables and by the distance between the radial cables (Gallery: Olympic stadium Berlin, Bucharest stadium). A lower membrane shell is often installed in the case of this structural shape - this ensures the covering of technical equipment under the roof (sound systems, ventilation, cables etc.).
The supporting structure of the membrane roof can be cable mesh structure, being either a supporting or a suspensory steel structure. Arched-, spire-, triangle- or square-shaped membranes can be designed for the cable structures.
In case of a rectangular auditorium seating - which is rather typical for stadiums with smaller capacity -, the supporting structure is usually made of steel main supports, on which, several membrane shapes can be designed, depending on the intended effect, the technical capabilities, the loads the membrane and the structure have to tolerate etc.
The application of so-called sliding mobile membrane roofs has nowadays become increasingly popular not only in the case of field covers, but for covering grandstands as well. In this case, the membrane moves on a guide-track, on so-called sliders fixed to a steel structure or to a wire rope mesh. The roof, adapted to the weather, can be moved via PC control.
The lightweight tensioned membrane cover can be used not only for covering auditorium seatings, but for covering the facade surfaces of stadiums and sports complexes as well. For facade covers, the side membranes can be used as spectacular visual elements (Gallery: Nagyerdei stadium), technical lighting elements (Gallery: Bratislava stadium, Wroclaw stadium, Kosice stadium) or as advertising surfaces (Wroclaw stadium).
High-tensile technical textile with PVC coating on both sides
Heavy duty material; tensile strength usually ranging between 2500 and 10000 N/5 cm; the surface is treated with UV-resistant additive; B-s1-d0 or B-s2-d0 fire classification; colour is usually white due to its light transmission features and accommodating effect; the lifetime of the material is averagely 15 years depending on the weather conditions.
High-tensile textile glass with PTFE (teflon) coating on both sides
Heavy duty, long-lasting material; tensile strength usually ranging between 3000 and 8000 N/5 cm; the UV-resistant and dirt-repellent additives of the surface and the teflon-coating of the ground texture (textile glass) ensure a lifetime of 25 to 30 years or more. It is often used for covering stadium grandstands and fields due to its durability; since it requires no maintenance, its costs are guaranteed to return with long-term application.
High-tensile textile glass with silicone coating
Similar characteristics as PTFE products, however, its production technology is closer to that of PVC-coated products.
Tenara fluoropolymer architectural membrane
Covered with high-tensile PTFE-based flexible fluoropolymer coating, particularly high light transmission, exceptionally long lifetime. This material is perfectly suitable for manufacturing sliding membrane roofs.
ETFE foil without cloth substrates
The heavy duty, UV-resistant and dirt-repellent ethylene tetrafluoroethylene foil without cloth substrate can resist most chemicals. It is used often in highly transparent colour to cover the field-close parts of covered grandstands (parts near the inner ring) as illuminating sections, so that it can provide adequate amount of natural light for the growth of grass. In case of stadiums, the foil is used as lighting section in 1 layer. ETFE material can be used to make complete roof or facade covers in 2-3-4 layers with inflated cushion design, so that the building can meet the thermal absorption and heat transmission specifications by constant aeration (with compressed air) between the layers.
The manufacturing technology of the materials used for stadium roofs is different in each stage.
Material testing protocols and test assessment shall be adapted to the project before cutting; the treatment of the materials during the cutting, the method of cutting (manual cutting or PC-controlled automated cutting with automatic cutter) and the determination of compensation values are all different.
The cut pieces of different sizes are assembled with so-called welding seams. Demands concerning welding technology, machines, and auxiliary materials providing welding strength are different for each material. Graboplan has the machines and hardware capacity required for the assembly of different materials.
In the final stage of the manufacturing, that is, in the stage of folding and packaging, the different materials are folded and packed in accordance with the order of on-site assembly and technology.
An important aspect during the folding of the materials is to avoid folding rough edges in order to maintain the integrity of the coating and of the fibres.
Graboplan provides the following services with regard to the covering of stadiums:
COUNSELLING, CONTRIBUTION TO THE PLANNING
The advices of our experienced engineers and manufacturing specialists concerning the roof structural and anchoring requirements of the subsequent membranes (reduction of the amount of steel required for the primary supporting structure, concept design of secondary auxiliary supports on the main support) should be taken into consideration at the stage of concept planning.
DEVELOPING THE CONCEPT, FORM-FINDING
The ideal membrane shape is developed by taking the local conditions – structure, anchoring, meteorological loads, roof type – into consideration with 3D form-finding analysis.
Preparation of scale model: before finalising the concept, it is possible to prepare a life-sized model to eliminate occasional planning errors and technical solutions that wouldn’t work in practice.
SELECTION OF MATERIALS, DETERMINING METHOD OF ANCHORING
The strength, quality and type of the load-bearing material required for the given roof or facade cover can be specified on the basis of preliminary static calculations, after the assessment of material tests. The type of the membrane anchoring can be finalised on the basis of the selected material, the type of the primary support, and on the basis of the preliminary static calculations.
ESTABLISHING THE BUDGET
The budget for the roof or facade membrane cover of a project can be prepared in light of the materials and the anchoring method.
DATA PROVISION FOR AUTHORISATION PROCEDURE
We prepare the membrane drawings, data provision concerning dynamics and preliminary designs for the authorisation design documentation of the construction as agreed.
PREPARATION OF PRODUCTION PLANS
The manufacturing of the tensioned membrane and of the anchoring will be performed on the basis of elaborated plans approved by the customer.
PREPARING PRODUCTION PLAN AND ASSEMBLY CONCEPT
Simultaneously with the selection of materials will the preparation of the manufacturing technology and assembly concept start, which, among others, shall include the performance of tests before, during and after the production, the determination of product control processes, procedural and final inspections, manufacturing technology, welding processes, folding and packaging concepts, the manpower and machinery needs of the on-site assembly, and the elaboration of proper assembly technology.
Technology and manufacturing capacities adapted to the dimensions and technical requirements of the project, using state-of-the-art machines: CAD/CAM computer-controlled plotter, high-frequency welding machines (for PVC-, PE- and PU-coated materials), pressing machines (for PTFE- and silicone-coated and Tenara materials).
We arrange the delivery of ordered products to any part of the world with shipping by road, by air or by sea.
Our group of experienced mechanics will perform the assembly of our tensioned membranes in any country of the world, under the supervision of Graboplan project managers: our mechanics have IRATA certificates, they are qualified to perform work at height, to operate machinery, they have personal protective equipment and special equipment for assembly.
PREPARATION OF DELIVERY DOCUMENTATION
Preparation of as-built drawings, specifications of materials installed, technical data sheets, declarations of performance with product-related user-maintenance instructions.