Enabling Works Notes

ENABLING WORKS Definition: Works carried out before construction that are needed to enable the main works to be carried out effectively. Temporary Roads - allow drainage - future road foundation for permanent way - strengthen existing roads for HGV traffic Demolition: - Blast it down (explosives) - Take it down (hand tools/piecemeals) - Knock it down/ Push it down (Swinging ball, pusher arm) Circular economy – Reduce, Reuse, Recycle, Repurpose TEMPORARY WORKS Definition: 1. To support or protect an existing structure/permanent works during construction 2. To support the vertical sides/side slopes of an excavation 3. To support an item of plant/equipment 4. To provide access EARTHWORK SUPPORT SYSTEMS Battered Excavation Propped Sheeting (Shoring)  Cross Lot Bracing  Rakers  Ground Anchors Sheet Piling - Steel sheets with interlocking edges driven to the ground Permanent or Temporary support Strutted Cofferdam - Used for the construction of repairs of dams, piers and bridges Two of the mai diaphragm w - to provid excavati permane round level are ng ve ground prior to n element of the Diaphragm W In diaphragm walling the wall is constructed in panels between 600 mm to 1500 mm thick and 5 metres long excavated with a specially designed clamshell grab to achieve the deep excavation depths required. The work commences with the construction of guide walls. The sides of the excavation are supported by bentonite slurry, which is introduced into the trench as the excavation proceeds and then removed and returned for reuse as the concrete is placed. In its most straightforward form, constructing alternate panels gives a straight joint between panels, and these are almost certain to allow water to seep between the panels. The introduction of steel tubes at the ends of the panels that are removed and grouted when the panels are complete helps to seal the joint against seepage. It is also possible to produce more shaped joints to provide interlocks to improve the structural integrity of the wall and its susceptibility to seepage. Contiguous and Secant Piles Soldier Piles (H-Piles) - Wide flanged H sections spaced 2-3m apart, driven prior to excavation - Horizontal timber sheeting/concrete planks (lagging) is inserted behind the flanges. FORMW Tempora sh conc FALSEW Support tructures SCAFFOLDING Provides safe and convenient working area, 2 metres above ground, for the workforce along with the materials and equipment. - A scaffold is a framework constructed from steel, fibreglass or aluminium tubes and connected by couplers – also called fittings – to support a work platform - Scaffolds may also be constructed from timber (up to 5 m high), and a range of proprietary systems are available. The vertical tubes are called standards and are connected by couplers to longitudinal horizontal tubes called ledgers and transverse horizontal tubes called transoms. - The work platforms may be either timber or steel, and are supported on transoms and putlogs – additional transverse tubes. - Top guard rails must be at least 900 mm above the work platform. Where mid-rails are used, they must be located so that the gaps between guard rail and mid-rail, and between mid-rail and platform are no more than 500 mm. - Toe boards are installed at the platform level so that tools or materials cannot fall off and be a hazard to anyone below. Toe boards must be continuous and a minimum of 150 mm high. If infill panels are used, they must have either a kick plate or a separate toe board. - Scaffold systems need to be secured by being braced or tied to a support structure or by using stabilisers. They must be braced in at least two directions, that is, longitudinal (or face) braced, traverse braced or plan braced. - When the scaffold height is more than three times the width of the base, the scaffold must be tied to a supporting structure. Alternatively, stabilisers or outriggers can be used to increase the base width. TYPES OF SCAFFOLDING 1. Single Scaffolding - Generally for brick masonry - Parallel to wall about 1.2m 2. Independent/Double Scaffolding - For stone masonry - The first row is 20 – 30 cm away from the wall and the other one is 1m away from the first row. 3. Putlog Scaffolding - The blade end of the putlog is usually placed horizontally and inserted fully into the brickwork joint, ensuring a full bearing is achieved 4. Cantilevered Scaffolding - the standards are supported on series of needles and these needles are taken out through holes in the wall. - Conditions: -When the ground does not have the capacity to support standards, -When the Ground near the wall is to be free from traffic, -When upper part of the wall under construction. 5. Trussed Out Scaffolding - A trussed-out scaffold is one of scaffolding the higher leve building without transferring the ground Edge Protection on Roof Scaffolds - Edge protection normally consists of guardrails and toe boards extended from an existing scaffold or installed and fixed into the perimeter walls or the edge of the roof. TWC AND TWS TWD The Temporary Works Designer is in charge of the ‘fit for purpose’ design of temporary works.