Construction projects involving excavation and trenching are among the most hazardous workplace activities. An excavation is identified as any man-made cut, cavity, trench, or depression that is formed by earth removal. The word “trench” is specific to underground excavations that are deeper than it is wide, being no wider than 15 feet. The fatality rate for all sorts of excavation job is 112% higher than that of general industry (U.S. Occupational Safety and Health Administration). Given this higher level of danger, it’s critical that safety precautions and controls be utilized all the time and that extreme care and patience be exercised when working in and around pits and excavations.
Both basic methods of protecting workers against cave-ins are sloping and temporary protective structures. Sloping involves cutting back the trench wall at an angle which is inclined from the work part of the excavation. The appropriate angle of the slope depends on the soil conditions on the site of excavation. Temporary protective structures are created to provide defense against cave-ins, collapse, sliding or rolling materials. Samples of temporary protective structures include shoring, trench boxes, pre-fabricated systems, hydraulic systems, and engineering systems.
Shoring is really a system that supports the edges or walls and normally requires the usage of aluminum, steel, or wood panels which can be maintained by screws or hydraulic jacks. Shoring should be carried out along with the progression of the excavation. When there is any delay between digging and shoring, no workers should enter the unprotected trench. Trench Boxes are often utilized in open areas which are far from utilities, roadways, and foundations. Trench boxes can be used to protect workers in cases of cave-ins, however are not just a substitute for shoring. When the trench or excavation walls are made of rock, rock bolts or wire mesh can be used to offer additional support.
trench jacks are strong steel tubular like instruments that consist of a 4 part system; A male section, female section, a winding collar along with a small stout pin. The Aluminum Trench Jacks essentially effort is by the female section accepting the male, allowing the two sections to become fully adjustable to a suitable height. The sections have holes inside them so the stout pin could be inserted to keep them fixed in your chosen height. The props can then further be adjusted by turning the winding collar.
At every end in the female and male sections will be a steel plate that is usually about 150 mm x 150 mm. The plate is there to help the trench jacks locate a suitable effect on both ground and the force to get supported.
There are a variety of methods to utilize trench jacks but probably the most common methods are by making use of them in conjunction with either timber needles or strongboys. Needles in construction are short stout timber beams, and an acrow prop will be placed towards each end, where the load being supported is within the middle. Strongboys are a more modern method where exvcgw 1 prop is necessary to fix for the strongboy, which often would then be placed in position to aid the stress.
If you want to support a wall and you will have chosen to make use of needles, then your method is usually to knock a couple of bricks with the wall large enough to set the needles through, and then each and every end an acrow prop would be placed and tightened up until it is tight in between the brick and ground level. It is a two man job and can be very trick to have the needles to balance whist setting them correctly in place.
Using strongboys is really a much easier method as it is usually merely a case of hacking out a mortar joint where load is going to be supported, and after that inserting the long, thin arm from the strongboy in. Similar to the needles method, the trench jacks are them tightened up securely. Some great benefits of using strongboys with the trench jacks however, is the fact that load only must be maintained by putting the props at one side from the wall.
It’s important to understand that collapses can happen unexpectedly, whatever the depth. Actually, the majority of fatalities occurs at minimal depths when workers forget to appreciate the risks involved. All excavation projects present serious safety risks, but injuries and fatalities as a result of collapses are preventable with proper planning and safety precautions.