page_title: Scaffolding
section_title: Ties
hierarchical_section_title: Scaffolding / Scaffolding today / Ties
caption_attribution_description: English: took using my mobile, 16 Aug 2008, in Vladimir. This is the Holy Trinity Church in central Vladimir.
context_page_description: Scaffolding, also called scaffold or staging, is a temporary structure used to support a work crew and materials to aid in the construction, maintenance and repair of buildings, bridges and all other man-made structures. Scaffolds are widely used on site to get access to heights and areas that would be otherwise hard to get to. Unsafe scaffolding has the potential to result in death or serious injury. Scaffolding is also used in adapted forms for formwork and shoring, grandstand seating, concert stages, access/viewing towers, exhibition stands, ski ramps, half pipes and art projects.
  There are five main types of scaffolding used worldwide today. These are Tube and Coupler components, prefabricated modular system scaffold components, H-frame / facade modular system scaffolds, timber scaffolds and bamboo scaffolds. Each type is made from several components which often include:
  A base jack or plate which is a load-bearing base for the scaffold.
  The standard, the upright component with connector joins.
  The ledger, a horizontal brace.
  The transom, a horizontal cross-section load-bearing component which holds the batten, board, or decking unit.
context_section_description: Scaffolds are only rarely independent structures. To provide stability for a scaffolding (at left) framework ties are generally fixed to the adjacent building/fabric/steelwork.
  General practice is to attach a tie every 4 m on alternate lifts (traditional scaffolding). Prefabricated System scaffolds require structural connections at all frames - i.e. 2–3 m centres (tie patterns must be provided by the System manufacturer/supplier). The ties are coupled to the scaffold as close to the junction of standard and ledger (node point) as possible. Due to recent regulation changes, scaffolding ties must support +/- loads (tie/butt loads) and lateral (shear) loads.
  Due to the different nature of structures there is a variety of different ties to take advantage of the opportunities.
  Through ties are put through structure openings such as windows. A vertical inside tube crossing the opening is attached to the scaffold by a transom and a crossing horizontal tube on the outside called a bridle tube. The gaps between the tubes and the structure surfaces are packed or wedged with timber sections to ensure a solid fit.
  Box ties are used to attach the scaffold to suitable pillars or comparable features. Two additional transoms are put across from the lift on each side of the feature and are joined on both sides with shorter tubes called tie tubes. When a complete box tie is impossible a l-shaped lip tie can be used to hook the scaffold to the structure, to limit inward movement an additional transom, a butt transom, is placed hard against the outside face of the structure.
  Sometimes it is possible to use anchor ties (also called bolt ties), these are ties fitted into holes drilled in the structure. A common type is a ring bolt with an expanding wedge which is then tied to a node point.
  The least 'invasive' tie is a reveal tie. These use an opening in the structure but use a tube wedged horizontally in the opening. The reveal tube is usually held in place by a reveal screw pin (an adjustable threaded bar) and protective packing at either end. A transom tie tube links the reveal tube to the scaffold. Reveal ties are not well regarded, they rely solely on friction and need regular checking so it is not recommended that more than half of all ties be reveal ties.
  If it is not possible to use a safe number of ties rakers can be used. These are single tubes attached to a ledger extending out from the scaffold at an angle of less than 75° and securely founded. A transom at the base then completes a triangle back to the base of the main scaffold.
caption: The Holy Trinity Church in Vladimir, with scaffolding wrapped in safety mesh.
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