Metal Bleachers and Grandstands in Dubai: Turnkey Fabrication
A metal bleacher or grandstand is a prefabricated structure made of steel supports, steps, seats and guardrails, designed to accommodate spectators at sports and mass events. Unlike permanent concrete grandstands, metal ones can be assembled in a few days, dismantled after an event or moved to another venue. In Dubai, metal bleachers are used at football stadiums, basketball and volleyball arenas, ice rinks, concert venues, school gymnasiums and exhibition centres. The main types of bleachers on the UAE market include fixed, telescopic, mobile and demountable.
Types of Bleachers
Fixed bleachers are installed on a permanent basis at outdoor stadiums and large indoor arenas. They have a concrete foundation and a fully welded steel frame. Such bleachers are designed for decades of use and withstand heavy loads.
Telescopic bleachers fold and unfold like an accordion. When folded, they take up minimal space and tuck away against the wall. When unfolded, they create a full spectator section with several rows. Telescopic bleachers are used in multi-purpose halls where the space is used for different activities, such as basketball today, a concert tomorrow and an exhibition the day after.
Mobile bleachers are assembled from individual sections that can be moved from place to place. They do not fold, but they can be easily disassembled into parts and transported on trucks. Mobile bleachers are used at temporary venues, festivals and travelling events.
Demountable bleachers sit between fixed and mobile. They are bolted to the floor or foundation but can be unbolted, dismantled and moved elsewhere if needed. Demountable bleachers are chosen by tenants and schools that are not sure the hall configuration will remain the same after a few years.
Construction and Components of Bleachers
A bleacher consists of a load-bearing frame, steps, seats and guardrails. The load-bearing frame is welded from hollow profile tube and channel. This includes supports, longitudinal and transverse beams that hold the entire structure. Steps are made from chequer plate steel or from aluminium planks with anti-slip coating. Step width ranges from eighty to one hundred twenty centimetres depending on how many spectators pass along the row. Step depth is at least eighty centimetres so that spectators can pass in front of seated people without bumping. Riser height between rows ranges from thirty to forty centimetres. Seats come in two types: continuous plastic benches for budget bleachers or individual chairs with armrests and backrests for high level stadiums. Guardrails are installed along the edges of bleachers and in aisles. Guardrail height is at least one hundred ten centimetres from the step to the top of the handrail.
Standard Dimensions and Requirements
Bleacher width must be a multiple of 2.3 metres, which is the standard section size. Depth of the first row from the guardrail to the first seat is at least forty centimetres so that spectators do not lean over the guardrail. Depth of all subsequent rows is eighty centimetres. Centre to centre distance between seats in a row is at least forty six centimetres. Seat backrest height is at least thirty centimetres. The height of the bleacher in rows must be a multiple of twenty or forty centimetres. For bleachers with a canopy, the clearance from the canopy to the last row is at least two metres.
What Bleachers Are Made From
The bleacher frame is made from steel hollow profile tube with square cross section from forty by forty to eighty by eighty millimetres and wall thickness from three to five millimetres. For main load-bearing beams, a channel with a height of one hundred to two hundred millimetres is used. Steps are made from chequer plate steel with a thickness of four to six millimetres. The chequer pattern prevents shoes from slipping on wet metal. Guardrails are made from hollow profile tube twenty by twenty or twenty five by twenty five millimetres. Seats are supplied separately, either plastic or aluminium. All steel elements undergo sandblasting to remove mill scale and rust, then are primed and coated with powder coating. For bleachers at outdoor stadiums in Dubai, the coating must be resistant to ultraviolet radiation and temperature variations. Hot dip galvanising of the frame is available upon customer request for maximum corrosion protection.
How Bleachers Are Designed
Design begins with measuring the room or outdoor area. Engineers record the length and width of the available space, ceiling height for indoor bleachers and the type of substrate, whether concrete, asphalt or soil. The client specifies the number of spectators to be accommodated. Based on this figure, the number of rows and the length of the bleacher are calculated. For sports events, the standard is one spectator per sixty centimetres of row length for continuous benches. For individual chairs, one chair per fifty to fifty five centimetres. Then the sightline angle is calculated. The optimal row rise gives each subsequent row an elevation of thirty to forty centimetres so that the head of the person in front does not block the view. At the same time, the load is calculated. For bleachers in Dubai, the live load from spectators is taken as four hundred to five hundred kilograms per square metre depending on the event category. Based on the load, the cross sections of all frame elements are determined.
How Bleachers Are Fabricated
Metal cutting. Hollow profile tube, channel and plate are cut to the dimensions shown on the drawing using band saws or CNC plasma cutters. Length tolerance is plus or minus one millimetre.
Bending and preparation. Tubes for handrails and guardrails are bent on a pipe bending machine to the required angles. Holes for bolted connections are drilled in components for demountable sections.
Section assembly. The bleacher is divided into transportable sections up to 2.3 metres wide and up to six metres long. Each section is assembled on an assembly jig. Supports are levelled, and beams are welded or bolted to the supports.
Welding. Welding is performed using a semi automatic welder in a carbon dioxide atmosphere. All welds on load bearing joints are double sided and continuous along the entire length of the connection. After welding, the welds are ground down to clean metal.
Quality control. Every weld undergoes visual inspection for cracks, porosity and lack of fusion. On step to beam connection joints, selective ultrasonic inspection is performed. The finished section is checked for geometry: horizontal alignment of steps, vertical alignment of guardrails, and section diagonals.
Corrosion protection. Finished sections are sandblasted to Sa 2.5 standard, meaning clean metal without rust or mill scale. Then primer is applied using airless spray. The finishing coat is powder coating. Coating thickness ranges from eighty to one hundred microns. For outdoor stadiums in Dubai's coastal zone, hot dip galvanising is offered.
How Bleachers Are Installed
Installation begins with preparing the substrate. Anchor points for supports are marked on the concrete floor. Holes for anchor bolts are drilled. Anchors are installed and tightened to the calculated torque. If the bleacher is fixed and very large, separate concrete foundations are poured under the supports. Then the sections are installed. Sections are bolted together. Steps, which are chequer plates, are placed onto the beams and welded or screwed down. Guardrails are installed after all steps are in place. Guardrail posts are attached to the ends of the steps or to special brackets on the beams. Handrails are welded to the posts. Seats are installed last. For continuous plastic benches, the material is cut to the row length and screwed to the steps. For individual chairs, each chair is attached to a bracket. After installation is complete, all bolted connections are checked and a walk test is performed. The bleacher is loaded with staff to check for squeaking, play or deformation.
Who Our Bleachers Suit
Owners of sports clubs and stadiums who need fixed bleachers for several thousand spectators. Schools and universities who need telescopic bleachers in gymnasiums for competitions and school assemblies. Concert and festival organisers who need mobile or demountable bleachers for temporary venues. Owners of exhibition centres who need telescopic bleachers that tuck away against the wall when the hall is used in exhibition mode. If you have the dimensions of the room or site and the required number of spectators, we provide a design and a commercial proposal.
