What You Need to Know About Different Shoring Techniques

Construction projects require lots of complex excavating and digging by machine or by hand. Often, this is done in ground that has been loosened up with heavy site traffic and other nearby excavation. On top of all this, there’s the issue of water, either from the ground itself or from rainfall. For all of these reasons, shoring techniques become a vital part of keeping structures and excavations in the ground stable, safe for workers and free of potentially costly collapses.

When is shoring used?

Construction site supervisors and engineers generally use shoring in a project whenever they want to offer support for:

• Excavated holes and trenches

• Walls being reinforced or repaired

• Enlarged openings and newly made gaps in or between structures

• Ground or structures that need to stay firm while a nearby structure is being demolished

• Structures that are being erected but aren’t yet permanently reinforced

These are just some major, basic examples of when shoring techniques can become critical. These technologies and procedures can however be used in all sorts of contexts and in construction or landscape development projects of nearly any kind. Most basically, whenever a hole is being dug in the ground or something needs to be kept from collapsing during renovation and construction, shoring is usually necessary.

Types of shoring techniques

There are various shoring techniques which are implemented by contractor nowadays, which are summarized as follows:

1. H and I-Beam Shoring

One of the most common shoring techniques used today is called H or I-Beam shoring. Another name for this process is soldier pile wall shoring. With this method, prefabricated steel H or I sections are driven or slid and vibrated into holes in the ground. In between these H or I beams, pre-cast concrete panels are then slid into place and installed. H or I-Beam shoring is especially useful for excavations between 4 and 15 feet or so in depth (1.2 to 5 meters), but can be reinforced carefully to handle deeper spaces in the ground.

2. Sheet Pile Shoring

With sheet pile shoring, you can create strong, long lasting and flexible results that can hold back heavy amounts of surrounding material. Because the corrugated thick steel sheets used for sheet pile shoring usually have to be driven into the ground, this technique is best done in soil that’s free of boulders or heavy rock saturation.

Sheet piles can then be installed, reinforced by horizontal steel beams and if the sheet sections of the piles are firmly fixed together and then welded, this shoring method can be powerful against ground water seepage. In fact, sheet pile shoring is particularly useful for excavations being built close to large bodies of water or ground water concentrations.

https://www.youtube.com/watch?v=LY86K15BfHw

3. Secant Pile Shoring

With secant pile shoring, you can intersect two walls together so that they interlock to create a continuous wall. One of these is called the primary wall and the other is called the secondary wall. The primary wall is the sturdier one but both are integral to the overall structure. Secant pile shoring is useful when open excavation is too difficult due to tight space or obstructing nearby structures. Secant pile shoring has to be carefully applied specifically because it’s often used so close to other standing structures.

4. Tangent, or Contiguous Pile Shoring

This visibly simple shoring method consists of strong, sturdily placed piles plowed into the ground and tightly spaced next to each other in a line (tangent) to each other. The cylindrical piles can’t however be packed together in a waterproof way and for this reason, tangent pile shoring is the exact opposite of sheet pile shoring in that it shouldn’t be used where there is a high-water table, lots of nearby water bodies or a risk of major water seepage. It is however useful for retaining excavations against lots of dry granular material or fairly dry clay soils.

5. Trench Boxes

First of all, it’s worth noting that trench boxes aren’t a deep excavation shoring technology. For major soil retention, they shouldn’t be used by themselves because their main purpose is rapidly installable trench shoring for worker protection in limited-depth trenches and excavations.

Therefore, trench box shoring does work extremely well for keeping soil and rock falls from pouring into trenches and holes where people are working. What’s more, the trench boxes themselves come in different sizes, can be rapidly lifted into place and can even have their width adjusted as needed for different trench widths. They’re an excellent rapid option for excavation security during pipe laying, underground cable work or other shallow excavation projects.

https://www.youtube.com/watch?v=KPQxsv8mcLA

Covering your shoring needs

When it comes to shoring materials, tools and technologies, buying or renting from suppliers with a long history of quality products and good maintenance track records is essential.

After all, these tools are being used for keeping hundreds of tons of dirt off off valuable employees and work projects. For extremely versatile and robust soldier pile wall shoring, sheet pile shoring or trench box shoring needs, ESC Group offers a wide range of solutions for nearly any construction project. Contact us for a custom quote on your specific needs.

Important Guidelines and Best Practices In Excavation Shoring Safety

One major cause of accidents in the construction industry is when open trenches/excavations start to cave in. In a study by A. Suruda, G. Smith, and S.P. Barker, at least seventy (70) workers die each year due to trench cave-ins.

Accidents and fatalities due to trench cave-ins can be mitigated with the proper implementation of construction safety standards, and the use of trench/excavation protection systems.

BEST PRACTICE IN EXCAVATION WORKS

Working in open excavations puts the workers at risk. It should be noted, however, that risks such as excavation collapse and other accidents can be prevented by observing excavation safety standards and practices.

The following should be considered before carrying out excavation works at the site:

Warning Signs and Barricades

Prior to the start of any excavation, warning signs and barricades should be placed along the perimeter of the excavation of the project site. This is done to enclose the working area for the project, and to let passing vehicles and pedestrians know that excavations works are being carried out at the area.

These signs and barricades should also have lighting and/or reflectorized components in order to be seen by vehicles and pedestrians at night.

Having a Certified Safety Officer on Site

Having a Certified Safety

Officer on site during excavation works is very important. A Safety Officer is a professional who has undergone training on basic occupational safety and health and must be certified by the Occupational Safety and Health Administration (OSHA).

The Safety Officer must be well-versed on the safety standards that must be implemented at the construction site. He/she is responsible in ensuring the safety of everyone working at the site. This includes inspecting the project site and identifying hazards that may compromise the safety of the workers and other individuals.

The Safety Officer must also ensure that protective equipment such as PPEs for the workers are worn, and the appropriate excavation protection system is correctly installed at the sides of the excavation prior to working.

Excavation Protection Systems

The use of excavation protection systems is imperative for excavations where sloping/benching of the excavation sides is not possible. This is also required when the underlying soil at the project site is predominantly loose or soft and may collapse easily.

Excavation protection systems such as sheet piles and trench boxes must be properly designed by a registered/professional design engineer.

Loads such as lateral earth pressure, surcharge from traffic and equipment loads, as well as hydrostatic pressure from the retained soil must be considered by the engineer to determine the most adequate and cost-effective excavation protection system.

The installation of such temporary structures prevents the collapse or cave-in of the retained soil while the excavation is open and/or people are working inside the excavation.

Figure 1. Typical trench shield/box (Source: OSHA)

Safe Access and Egress Points

Ingress and egress points allow workers to access the excavation safely. It is required by OSHA 2226-10R that excavations should have ladders, steps, and ramps installed at the site for excavations having depths of 4.00 feet (1.22 meters) or deeper.

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In line with trench shields/boxes, the ladders, steps and ramps should also be properly designed and installed at the site to prevent accidents while carrying out construction works in the excavation.

WORK SAFE WITH ESC TRENCH SAFETY SOLUTIONS

https://www.youtube.com/watch?v=KPQxsv8mcLA

ESC Steel offers a wide range of trench shield/protection products that can be installed for various open trench/excavation projects.

These products have been used on numerous projects across the globe, and it is proven to be effective in preventing soil cave-ins and collapses.

Safety Measures in Excavation and Trenching

Occupational Safety and Health Administration (OSHA) believed that rate of deaths and serious injuries resulting from trenching and excavation incidents, especially collapses, can be significantly reduced. If OSHA concentrates resources to deal with trenching and excavation operations through strict enforcement especially effective and close monitoring activities at construction sites. With this vision, OSHA came up with significant updates to CPL 02-00-069 - Special Emphasis: Trenching and Excavation, of 1985.

As far as modern protective systems is concerned, OSHA recognizes slope establishment, benching, shoring, and the use of Trench Shields as legitimate ways of protecting workers in a trench.

Sloping involves profiling the sides of soil so that the top of the trench is wider than the bottom of the trench. For trenches in Type C soil, OSHA requires 18 inches of width for every 12 inches of depth (53 degrees). For Type B soils, its 12 inches of width for every 12 inches of depth (45 degrees). And for Type A soils, its 9 inches of width for every 12 inches in depth (34 degrees). The stability and condition of sloped soil is however not guaranteed to be permanent during a period of time.

Type A - Examples include: clay, silty clay, sandy clay, and clay loam.

Type B - Granular cohesion less soils. Such as angular gravel, similar to crushed rock, silt, silt loam, sandy loam. And in some cases, silty clay loam and sandy clay loam.

Type C - Granular soils, including gravel, sand, and loamy sand. Submerged soil or soil from which water is freely seeping. Submerged rock that is not stable, or material in a sloped, layered system where the layers dip into the excavation.

Shielding uses trench shields or trench boxes and is very effective in preventing soil collapses. In this method, it is important to pick the product that is right for each soil type. Trench shields are composed of two large plates held across by four cross members, and the plates are positioned to extend about 18 inches higher than anything that can cave-in.

Benching is similar to sloping, but instead of the top of the trench wall gradually meeting the bottom of the trench by a straight line, it is a series of “steps” (perhaps 1 foot wide for every foot deep). The trench wall looks like a flight of stairs, which is great for ingress and egress, but it can’t be applied in Type C soils. Similarly with slopes, the condition and profile of soil may change in short period due to many factors especially weather.

Shoring uses various support systems including timber, aluminum, and steel to prevent soil and the trench walls from moving. When using this method, walings or vertical shores are distributed throughout the trench and each one stretches the width of the trench. The ultimate purpose of shoring is to prevent cave-ins by making sure trench walls are supported at all times and will not collapse.

In brief, the shoring/strutting system consists of tubes or H beams as compression struts, and H beams as

a waling to redistribute the horizontal forces over the struts. One example of a trench shoring product is ESC’s Trench Shoring or Strutting Systems. ESC has experience both designing, supplying and installing trench shoring/strutting systems in various configurations and project conditions. They can deliver completely customized strutting systems including all necessary prefabricated components.

Further product information can be found in www.esctrenchshoring.com.

Proper selection of materials and systems to employ for a job might be critical in preventing incidents. But the main key to a safe and healthful work environment is still a comprehensive injury and illness prevention program.

Trench Shield stocks

With management leadership, worker participation, hazard identification, hazard prevention and control, education and training, and program evaluation & improvement.

For trench shoring solutions, ESC has wide range of products to choose from including but not limited to the Standard Trench Shield, Manhole Trench Shield, and Adjustable Trench Shield. There are also various spreader solutions including telescopic spreaders.

ESC shoring systems have been relied on by Contractors for over 30 years, and the trench shield range is one of their most utilized products.