Tensioned membranes can be used for the characteristic, lightweight covering, shading and decoration of structures of any dimensions and in any style, on the basis of custom plans.
Tensioned membranes are temporarily or permanently installed lightweight structures that have many advantages in contrast to other structures made of conventional building materials. The variety of shapes makes it possible to implement any architectural ideas, and their installation is much faster in contrast to conventional building materials.
Perfectly suitable for covering spaces or hallways between two buildings, but may also form an individual and spectacular part of any smaller or larger square, park or other public space by mounting to structures with proper dimensions.
This is one of the most spectacular and popular pieces of modern architecture, since the density and depressing nature of steel structures can be compensated perfectly by entirely exploiting the advantages of the material, and by using lively tensioned membranes of different shapes.
Tensioned membranes are always custom manufactured and implemented in accordance with the architectural concepts and local conditions.
Tensioned membrane structures can be used in the most diverse shapes and in the greatest extent: available in single- and multi-layered versions (with two-three-four layers) depending on the intended use.
ADVANTAGES OF USING TENSIONED MEMBRANES
- favourable quality/price ratio compared to conventional structures
- the membrane structure has lighter dead weight and smaller transport volume
- can be installed with lower assembly costs
- long-lasting with minor maintenance demands
- energy-efficient heating and cooling of structures with closed interior spaces
- inner air-conditioning as required by applying different thermal insulation procedures
- aesthetically (material+shape+colour) adapted to the built or natural environment
- suitable for advertising purposes
- special lighting provides extraordinary visual effects
- easy maintenance and cleaning
STRUCTURE AND SHAPES
The supporting structure of tensioned membranes is always a fitted supporting structure, which could be made of steel, wood, concrete, wire rope or any other solid material capable of tolerating the tension forces of the membranes. The type of the supporting structure is determined by the architectural concepts, the budget and the function.
When using steel support, the tensioned membrane usually has the shape of a saddle, the final shape of which is determined by the arched steel or wooden support installed between the two main supports.
The curved barrel-shaped tensioned membranes are also anchored to a fixed support, while the supporting structure of butterfly-, sail- and spire-shaped tensioned membranes is usually anchored with wire ropes, with supporting structure of pendulum bearing. Usually, no intermediate reinforcement is required for inflated structures, depending on the size of installed membrane units, and on what meteorological loads will have be taken into consideration during the planning. The final shape of the tensioned membrane will depend on the material and the anchoring method, regardless of the size. The material used in this case is a UV-resistant and dirt-repellent material with proper tensile strength, which can be expanded in both directions, and which has been developed specifically for architectural membrane applications. The anchoring is always designed according to the shape of the membrane and the nature of the supporting structure.
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.