All construction operations carry inherent risks, but excavations are widely recognized as being among the most dangerous. Cave-ins and trench collapses pose a grave threat to worker safety, as they cause fatalities and injuries every year. The erection of the proper shoring keeps workers safe. Engineers must assess the type of soil in the area before they can determine the proper method for building shoring.
Identifying Stable Rock
The Occupational Safety and Health Administration (OSHA) recognizes four categories of soil and rock deposits. The first is stable rock, such as granite or sandstone. Solid rock can be safely excavated with vertical sides, as it will remain intact. However, before classifying a deposit as solid rock, the engineer must determine whether the rock contains cracks.
Identifying Type A Soil
Type A soils are typically clay, clay loam, and silty clay. These are cohesive soils that feature an unconfined compressive strength of 1.5 tons per square foot or greater. Note that no soil may be classified as type A if any of the following are applicable:
- It’s part of a sloped, layered system
- It’s been previously disturbed
- It’s fissured
- It’s been subjected to vibrations
- It has seeping water
Identifying Type B Soil
Type B soils are also cohesive soils. Typical examples include angular gravel, silt loam, silt, and dry, unstable rock. Type B soils have an unconfined compressive strength between 0.5 and 1.5 tons per square foot. It’s also possible for a soil to be classified as type B if it’s been subjected to vibrations or fissures, but would otherwise be classified as type A soil.
Identifying Type C Soil
Some examples of type C soils are gravel, sand, submerged soil, loamy sand, soil with seeping water, and unstable, submerged rock. On construction sites, it’s most common for deposits to be classified as type C. These cohesive soils have an unconfined compressive strength of less than 0.5 tons per square foot.
If your company is planning excavation work, you can count on the expertly trained team at Scaffold Resource to provide safe, compliant shoring erection services. Call us at (301) 924-7223. We also offer scaffolding rentals near Washington, D.C.
Workplace safety must be a top priority for construction companies. There are inherent risks involved with major projects like shoring erection and scaffolding work, and one of those risks is the possibility of head injuries. All employees should wear hard hats whenever there is a potential for falling objects, accidental head contact with electrical hazards, or contact between a fixed object and an employee’s head.
This video offers a simple demonstration of why hard hats are so important. “Melanie,” a watermelon, is wearing a hard hat the first time a brick falls on her. As you can see, there is no cranial damage. The second time the brick falls on Melanie, she lacks a hard hat, and the damage is considerable.
Scaffold Resource in Washington, D.C., is a recognized leader in on-the-job safety because we firmly believe that even one serious injury is too many. To have our highly trained, safety-minded employees provide scaffolding or shoring erection for your jobsite, call (301) 924-7223.
Jobsite accidents like collapsed walls are every construction manager’s worst nightmare. Even if the accident occurs during off-hours when no employees are present, a collapsed wall can easily lead to major headaches, including construction delays and higher insurance premiums. Only a strict adherence to OSHA regulations and industry standards regarding wall bracing safety can prevent this type of accident from happening in almost any circumstance.
Understanding the OSHA Regulations and Industry Standards
The OSHA regulations are uncharacteristically minimalist regarding wall bracing safety. The main code requirement is that all masonry walls taller than eight feet must be adequately braced until the permanent supporting structures are installed. Because the official regulations can be subject to interpretation, the Mason Contractors Association of America (MCAA) developed its own industry standards. This resulted in the widely accepted and used Standard Practice for Bracing Masonry Walls under Construction guidelines. Mason contractors and project managers are strongly encouraged to follow the Standard Practice and consult its tables regarding the proper installation of bracing.
Establishing the Restricted Zone
One of the first steps for proper wall bracing is to establish the restricted zone based on the wall’s height. The restricted zone should be on the side of the masonry wall opposite the scaffolding, if scaffolding is up. Once the scaffolding is removed, the foreman must establish the restricted zone on both sides of the wall. For the sake of simplicity, mason contractors can tape off the restricted zone based on the height the wall will be once it’s completed. Otherwise, the boundaries must be re-established as the wall grows higher.
Designing the Wall Bracing
For maximum protection from damaging winds, a minimum of two braces must be installed for each wall panel. Note that the national Building Codes prohibit a space greater than 25 feet between control joints. Finally, there must be 20% of the wall between any given brace and the nearest control joint.
Scaffold Resource is a leader in construction site safety. We provide safe wall bracing, shoring erection, and scaffolding rentals at sites in Washington, D.C., and the surrounding areas. Call us today at (301) 924-7223 and let us know how we can help you make your construction zone as safe as possible.
Hoisting and rigging are common features in construction zones where large amounts of materials must be transported up and down scaffolding. OSHA requires that only qualified and properly trained operators be allowed to work with hoisting and rigging equipment. Furthermore, all hoisting and rigging equipment should be carefully inspected prior to use to ensure the safety of everyone on the jobsite. Construction managers may find it safer to rely on contracted hoisting experts from an outside firm. Continue reading to learn more about hoisting.
Slings are commonly used to hoist suspended loads. Wire rope is among the most commonly used materials for slings, as it is capable of withstanding heavy loads and adverse conditions. Some wire ropes feature a fiber core. The outer shell is comprised of individual wires twisted to form strands, which are then twisted together to form the rope. The fiber core gives the wire rope greater flexibility, but lowers its resistance to damage. If greater strength and heat resistance are desired, then it’s best to choose a wire rope with a wire core.
Chain slings are ideal because they easily adapt to hold bulky loads and unusually shaped objects. The alloy steel is also strong, but sudden shock can result in damage and potential failure of the sling. Before using a chain sling, the operator should visually inspect it for signs of damage from wear and tear, including gouging, stretching, and nicking.
Fiber Rope and Synthetic Web
Fiber rope and synthetic web slings aren’t as strong as wire rope or chain slings. However, depending on the specific composition and size, they can still handle loads of up to 300,000 pounds. These slings are primarily used for highly delicate or finished loads. It should be noted that, due to their susceptibility to caustic materials, fiber rope slings shouldn’t be used near acids or other caustics.
Could your construction site benefit from the expertise of engineers who are well-versed in hoisting challenges? Contact Scaffold Resource today at (301) 924-7223 to discuss your project. We’re known for providing safe tube and clamp scaffolding in Washington, D.C., but we also offer shoring and hoisting services.