The Occupational Safety and Health Administration (OSHA) website categorizes excavation as one of the most potentially hazardous construction jobs. To counteract these concerns, OSHA has clear construction propping system requirements detailing soil type in relation to shoring and propping equipment.
Types of Shoring For Excavation: How to Keep Workers Safe.
A construction propping system will be required for nearly all excavation operations. The main concern is the safety of the workers involved. Determining the right shoring equipment for each job comes down to understanding the classification of soil and the depth of the excavation.
When is Construction Propping Equipment Required on a Job?
OSHA defines an excavation as a man-made trench, depression, or cut in which soil was removed. Specifically, an excavation qualifies as a trench if it is no wider than 15 feet, and deeper than it is wide. Any trench that exceeds a depth of five feet is required by OSHA to install an appropriate shoring system, unless the trench is made entirely out of rock. In fact, trenches that exceed 20 feet in depth need to have their construction propping system reviewed by a registered professional engineer.
What Types of Soil Classification Are There, And What Trouble Might Occur?
There are five basic categorizations for soil. Solid rock is its own category, and as mentioned above, does not require shoring. Then there are the three types:
Type A: These soils are types of clay and loam, or cohesive soils.
Type B: These soils might be angular gravel, or types of silt such as silt-loam.
Type C: These soils may be gravel, sand or submerged sand or soil, or even unstable submerged rock.
Layered Geological Strata. When the soil presents as stratified layers, the strength of the weakest layer is measured.
Excavation Shoring Methods Are Based on Both Soil Classification and Type Of Trench.
Construction propping systems vary in support. Choosing the wrong option could be potentially fatal. Some types of shoring, such as hydraulic shoring, are light weight enough that they can be installed by one person. Other methods, such as pneumatic shoring, require special equipment such as an air compressor to be on sight for installation. No matter which type is chosen, the shoring must be inspected before work begins each day and at the end of shift to ensure the support system hasn’t shifted, nor has the excavation begun to cave. Fissures and cracks in the sides of the trench are also a serious concern that must be monitored.
Shoring is an absolute requirement for those excavation trenches that measure a depth of more than five feet. The safety of the construction workers is paramount.