Scaffolding is a type of temporary structure that helps workers and moving materials during the construction, maintenance, and repair of buildings, bridges, and other structures. It’s also widely known as scaffold or staging, to most of us.
People often use scaffolds at construction sites to reach high places or areas that are difficult to access, like for example the roof or the high ends of a wall to do some paintwork.
If the scaffolding is not safe, it can cause fatal accidents, severe injuries, or even death, though there are not many reports of it. People use scaffolding for various purposes such as formwork and shoring, grandstand seating, concert stages, access/viewing towers, exhibition stands, ski ramps, half pipes, and art projects.
Today, people use five primary types of scaffolding across the world. These components are used in scaffolding systems. They include tube and coupler fittings, prefabricated modular components, H-frame, and façade modular systems, as well as timber and bamboo scaffolds. (mainly in China and India).
Usually, each type comprises various components, which may include:
· A base jack or plate is a type of base that supports the weight of the scaffold.
· The standard consists of an upright component that is connected by connectors.
· The ledger is a type of brace that is positioned horizontally.
· The transom is a part of the structure that supports weight horizontally. It holds the batten, board, or decking unit in place.
· One option for bracing is to use diagonal and/or cross-section components.
· The working platform is made using a component called batten or board decking.
· A coupler is a type of fitting that is used to connect different components together.
· A scaffold tie is a tool that is used to secure the scaffold to structures.
· Brackets are utilized to widen the working platforms.
When scaffolds are used as temporary structures, they often require specialized components to make them safe and functional.
These components may include heavy-duty load-bearing transoms, ladders, or stairway units to allow workers to get on and off the scaffold, beams, ladder or unit types to span obstacles, and rubbish chutes to remove unwanted materials from the scaffold or construction project.
A Basic Scaffold Structure
The standard, ledger, and transoms are the main components of the framework. The vertical tubes known as standards, also known as uprights, are responsible for transferring the complete structure’s weight to the earth. To distribute the load, they sit on a square base plate. The base plate, which is occasionally pinned to a sole board, has a shank in the middle to support the tube.
The horizontal rods that link the standards are called ledgers. Ledgers are supported by transoms at an inclination. The major transoms are positioned next to the standards; they support the boards and keep the standards in place. The intermediate transoms are positioned in between the main transoms to add additional support for the boards. This fashion is known as “English” in Canada. American is less common but has benefits in some circumstances because the transoms are connected to the standards.
Cross braces, which add stiffness in addition to the right-angled tubes, are positioned crosswise from ledger to ledger next to the standards to which they are attached. Ledger braces are the name given to the braces if they are attached to the ledgers. A facade brace is attached to the scaffold’s face every 30 meters or so at an inclination of 35° to 55°, extending vertically from the bottom to the summit of the scaffold, to reduce sway.
A right-angle coupler should be used to connect non-board-bearing transoms. Putlog or single couplers join board-bearing transoms to ledgers. Right-angle couplers join ledgers or transoms to standards. Tubes can be connected at any other position using swivel couplers. To prevent happening at the same level in adjacent standards, the actual joints are spaced apart.
The fundamental scaffold components are spaced pretty uniformly. The highest bay length for a general-purpose scaffold is 2.1 m, the bay area is lowered to 2 or even 1.8 m for heavier work, and a bay width of up to 2.7 m is permitted for examination.
The lowest breadth permitted is 600 mm, but a more typical four-board scaffold would be 870 mm broad from standard to standard. The scaffolding width is decided by the width of the boards. It may be necessary to use 5, 6, or even up to 8 board widths for heavier support. To close the space between the interior standard and the structure, an inside board is frequently inserted.
Although the base raise can be up to 2.7 m, the lift height, or the distance between ledgers, is 2 m. A kicker lift, which is only about 150 millimeters above the earth, is also depicted in the above image.
The thickness of the boards being held determines the transom spacing; 38 mm boards need a transom spacing of no more than 1.2 m, whereas a 50 mm board can withstand a 2.6 m transom spacing, and 63 mm boards can have a maximum spread of 3.25 m. All boards must have a minimum overhang of 50 millimeters and a maximum overhang that is no greater than 4 times the width of the board.
Scaffolding Foundation
Having a strong foundation is very important. In many cases, scaffold frameworks need more than just basic base plates to ensure that the load is properly supported and distributed in a safe manner. You can use scaffolding on concrete or other hard surfaces without base plates, but it’s always better to use them. If you want to lay a surface like pavement or tarmac, you’ll need to use base plates.
If you’re dealing with a surface that’s soft or uncertain, it’s important to use sole boards. When using a single standard, the sole board should have a minimum area of 1,000 square centimeters (160 in2) and no dimension less than 220 millimeters (8.7 in). Additionally, the thickness of the sole board should be at least 35 millimeters. (1.4 in). If you need a stronger scaffold, you may need to use larger beams that are set in concrete.
When working on an uneven surface, it’s important to cut steps for the base plates. It’s recommended to make the steps at least 450 millimeters (18 inches) in size. For a platform to be safe and functional, it needs to have certain other elements in place. The structure needs to have close-boarded walls and two sets of guard rails for safety, as well as toe and stop boards to prevent slips and falls. It is important to ensure that access is safe and secure.
Scaffold Ties
It is uncommon for scaffolds to exist as standalone structures. In order to make sure that a scaffolding framework is stable, it is common practice to attach ties to the nearby building, fabric, or steelwork.
Usually, people attach a tie every 4 meters on every other lift. (traditional scaffolding). When using Prefabricated System scaffolds, it’s important to have structural connections at every frame, which are typically spaced 2-3 meters apart. The manufacturer or supplier of the System will provide the necessary tie patterns. The ties should be attached to the scaffold as near as possible to the point where the standard and ledger meet, which is also known as the node point. Scaffolding ties are now required to support both tie/butt loads (positive and negative) and lateral (shear) loads, as per the latest regulations.
Because scaffold structures can vary in nature, there are various types of ties that can be utilized to seize opportunities.
People usually pass ties through openings in structures, like windows. A tube that runs vertically inside the opening is connected to the scaffold using a transom. On the outside, a horizontal tube that crosses the opening is known as a bridle tube. To make sure everything fits together securely, we use timber sections to pack or wedge the gaps between the tubes and the structure surfaces.
Box ties are used to connect the scaffold securely to pillars or similar structures. They added two more transoms on either side of the lift feature and connected them with shorter tubes called tie tubes. If it’s not possible to do a complete box tie, you can use an L-shaped lip tie to hook the scaffold onto the structure. To prevent the scaffold from moving inward, you can add a butt transom that’s placed tightly against the outside of the structure.
In certain situations, anchor ties (also known as bolt ties) can be utilized. These ties are installed into holes that have been drilled into the structure. One type that is frequently used is a ring bolt that has an expanding wedge. This type of bolt is then fastened to a node point.
A reveal tie is the least intrusive type of tie. These utilize an aperture in the structure but employ a horizontally wedged tube within the aperture. Typically, the reveal tube is secured using a reveal screw pin, which is a threaded bar that can be adjusted, along with protective packing located at both ends. A tube called a transom tie connects the reveal tube to the scaffold. It’s not a good idea to have too many reveal ties because they can be unreliable and require frequent adjustments. It’s best to limit them to less than half of your tie collection.
If using a safe number of tie rakers is not feasible, then one can resort to using tie rakers. These are individual tubes that are connected to a ledger and extend out from the scaffold at an angle of fewer than 75 degrees. They are firmly secured. At the base of the main scaffold, there is a transom that forms a triangle back to the base.
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