When a building is erected, scaffolding is used to provide external structural support for both the building-in-progress and the people working on it. Materials, such as metal piping or tubing, are often used as the back bone of scaffolding, in addition to couplers and boards. Regardless of material, however, scaffolding must adhere to European standards for performance requirements and structural design methods. Because scaffolding must be compatible with a wide array of buildings and structures, there are numerous kinds of scaffolds to meet specific building requirements. However, all scaffolding is comprised of the same basic elements, though the manner in which they are designed and the way such elements fit together can vary.
Basic scaffolding elements include three general components: standards, ledgers and transoms. A standard is a long pipe or tube that connects the mass of the scaffold directly to the ground, and it runs the length of the scaffolding. The base of each standard is connected to a base plate, which helps distribute the weight each standard bears. In between each standard, running horizontally, is a ledger, which adds further support and weight distribution. Transoms, placed on top of ledgers at a right angle, come in several different forms. Main transoms provide support for standards by holding them in position as well as supporting boards. Intermediate transoms are placed alongside main transoms to lend additional board support.
In addition to standards, ledgers and transoms, there are several other supportive elements that serve to reinforce the fundamental scaffolding. Braces, such as Cross braces, façade braces, and additional couplers, can be used in varying combinations to support the structure in several ways. Cross braces run diagonally between ledgers and securely attach to standards to increase a structure’s overall rigidity. However, the can also secure themselves to ledgers, in which case they are simply called ledger braces. Façade braces help prevent a structure from swaying, and are attached on the face of the scaffold, running the length of the face of the structure and securely attaching at every level.
Couplers help connect structural elements, and come in several variants. To connect a ledger or transom to a standard, a right-angle coupler should be used. If a transom supports a board and must be connected to a ledger, a putlog or single-coupler should be used to connect the ledger to the transom. For any other angle of connection between scaffold piping, a swivel coupler is recommended.
The length, width, and height of each scaffold element can vary with each building, but there are several basic measurements for each basic component. General width of a scaffold is typically determined by the width of the scaffolding boards. The height between ledgers, also called lift height, is usually between 2 and 2.7 meters. Transom placement depends on board thickness. If the board is 38 mm thick, transoms should be 1.2 meters apart, at the most. A 50 mm thick board requires that transoms be no more than 2.6 meters apart.
In addition to the basic structural elements of a scaffold, there are multiple kinds of ties that secure a scaffold to the adjoining building. As a general rule, ties are attached every 4 meters on alternating lift levels. However, depending on the kind of scaffold, the tie patterns and types of ties used can vary. Through ties, for example, can be used to secure a scaffold to a building by entering a building’s open window. Box ties help secure a scaffold by attaching to a building’s external features, such as strong pillars.
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