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Shoring
Shoring is the process of temporarily supporting a building, vessel, structure, or trench with shores (props) when in danger of collapse or during repairs or alterations. ''Shoring'' comes from ''shore'', a timber or metal prop. Shoring may be vertical, angled, or horizontal. Methods Buildings Raking shores In this method, inclined members called rakers are used to give temporary lateral support to an unsafe wall. One or more timbers slope between the face of the structure to be supported and the ground. The most effective support is given if the raker meets the wall at an angle of 60 to 70 degrees. A wall-plate is typically used to increase the area of support. Foundations Shoring is commonly used when installing the foundation of a building. A shoring system such as piles and lagging or shotcrete will support the surrounding loads until the underground levels of the building are constructed. Commonly used shoring equipment includes post shores, shoring beams, and timber jacks ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trench Shield
Trench shields (also called trench boxes or trench sheets) are steel or aluminum structures used for protecting Public utility, utility workers while performing their duties within a trench and avoid Cave-in (excavation), cave-ins. They are customarily constructed with sidewalls of varying thicknesses held apart by steel or aluminum spreaders. Spreaders can be interchanged to match the width of the trench. The different materials and building designs lead to a variety of depth ratings: the depth of a trench that the shield can withstand a collapse without buckling. Depth ratings are determined by registered professional engineers. A shield should not be confused with a shore. While they may serve the same function, trench shoring is a different physical application that holds up the walls of a trench to prevent collapse. In the US, use of a trench shield is governed by Occupational Safety and Health Administration, OSHA 29 CFR Part 1926.650-.652 Subpart P-Excavations. Exte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Box Crib
A box crib or cribbing is a temporary wooden structure used to support heavy objects during construction, relocation, vehicle extrication and urban search and rescue. It is commonly used to secure overturned motor vehicles, and debris within collapsed buildings. Cribbing is often used in conjunction with other stabilization equipment, such as pneumatic or hydraulic shoring. Cribbing is also used in sub-surface mining as a roof support. Cribbing has largely been replaced by hydraulic shoring in modern mining applications. Some forms of cribbing can be used on movie sets and/or production sites for stabilizing dolly tracks, platforms, and various temporary structures when quick setup times are needed. Stability The stability of a crib is affected by a variety of factors: the material used (often a soft wood which gives audible warnings before failure), the number of contact points between the crib and the supported surface, the ratio of the footprint of the crib to its height, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
House Raising
House raising (house lifting, house jacking, barn jacking, building jacking) is the process of separating a building from its foundation and temporarily raising it with hydraulic screw jacks. The process is the first step in structure relocation in which the building is moved to a different location. House raising may also be a part of a renovation to build a foundation under an existing house or make a house larger by building a new floor level creating a two-story house. Often employed in areas that are prone to flooding and storm damage, this process can be achieved through the use of either timber piles or helical piles. Once a house is raised and supported on cribbing, a new foundation can be constructed beneath it. After Hurricane Katrina and Hurricane Sandy large numbers of houses in parts of Louisiana, New York and New Jersey were raised to avoid future flooding. Other house raising technologies include the ArrowLift structural lifting system which is an alternative to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wall-plate
A plate or wall plate is a horizontal, structural, load-bearing member in wooden building framing. Timber framing A plate in timber framing is "A piece of Timber upon which some considerable weight is framed...Hence Ground-Plate...Window-plate bsolete.." etc. Also called a wall plate, raising plate,Sturgis, Russell. ''Sturgis' illustrated dictionary of architecture and building: an unabridged reprint of the 1901-2 edition''. 1901. Reprint. Mineola, N.Y.: Dover, 1989. 159. Print. or top plate,Sherwood, Gerald E., and Robert C. Stroh. ''Wood-frame house construction''. Washington, D.C.: U.S. Dept. of Agriculture, Forest Service :, 1989. 54. Print. An exception to the use of the term plate for a large, load-bearing timber in a wall is the bressummer, a timber supporting a wall over a wall opening (see also: lintel). These are common in Australia. The terms sole plate or sill plate are used for the members at the bottom of a wall at the foundation but are most often just called ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Falsework
Falsework consists of temporary structures used in construction to support a permanent structure until its construction is sufficiently advanced to support itself. For arches, this is specifically called centering. Falsework includes temporary support structures for formwork used to mold concreteHardie G.M. (1995) Building Construction: Principles, Practices, and Materials. New Jersey: Prentice Hall. (Pg 116, paragraph 1) in the construction of buildings, bridges, and elevated roadways. The British Standards of practice for falsework, BS 5975:2008, defines falsework as "Any temporary structure used to support a permanent structure while it is not self-supporting." History Falsework has been employed in bridge and viaduct construction since ancient times. The Romans were renowned for its use, as at the Limyra Bridge in Turkey. Until the turn of the 20th century almost all falsework was constructed from timber. To compensate for timber shortages in different regions and to rati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dog (engineering)
In engineering, a dog is a tool or part of a tool, such as a pawl, that prevents or imparts movement through physical engagement. It may hold another object in place by blocking it, clamping it, or otherwise obstructing its movement. Or it may couple various parts together so that they move in unison – the primary example of this being a flexible drive to mate two shafts in order to transmit torque. Some devices use dog clutches to lock together two spinning components. In a manual transmission, the dog clutches, or "dogs" lock the selected gear to the shaft it rotates on. Unless the dog is engaged, the gear will simply freewheel on the shaft. This word usage is a metaphor derived from the idea of a dog (animal) biting and holding on, the "dog" name derived from the basic idea of how a dog jaw locks on, by the movement of the jaw, or by the presence of many teeth. In engineering the "dog" device has some special engineering work when making it – it is not a simple part to ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unit Load Device
A unit load device (ULD) is a container used to load luggage, freight, and mail on wide-body aircraft and specific narrow-body aircraft. It allows preloading of cargo, confidence the containerised load will fit in the aircraft and efficient planning of aircraft weight and balance and reduced labour and time in loading aircraft holds compared with 'bulk-loading' single items of cargo or luggage by hand. Each ULD has its own packing list or manifest so that its contents can be tracked. A loaded aircraft cargo pallet secured with a cargo net also forms a ULD, but its load must be gauged for size in addition to being weighed to ensure aircraft door and hold clearances. The IATA publishes ULD regulations and notes there are 900,000 in service worth more than US$1 billion, averaging $ each. Types ULDs come in two forms: pallets and containers. ULD pallets are rugged sheets of aluminium with rims designed to lock onto cargo net lugs. ULD containers, also known as cans and pods, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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