What is the proper vinyl sheet pile driving method for different soil types?

“Pitch and drive” method is the most practical way of pile driving in loose soils especially when using short piles. Also called “set and drive”, this method installs piles one by one. However, with only one interlock in control, sheet piles have high tendencies of rotating from the axis and leaning forward or backward. Panel driving is recommended for the dense deposit of sands and compact cohesive soils such as heavy clay or in presence of obstructions. In this method, a number of piles are interlocked together before driving. The panel of piles is supported by guide frames and driven gradually in sequence, sometimes in a staggered manner. The method can achieve installations of longer piles in more difficult ground conditions with better results in sheet pile alignment and verticality. In cases of difficult ground conditions such as hard strata and the presence of obstructions, driving assistance is employed along with a proper selection of driving method and equipment. Jetting and drilling help by loosening or eliminating obstructions by creating pressure right under the tip of the sheet pile being driven. Long and slender PVC sheet piles require steel mandrels as supports when driven in such conditions. Mandrel, which shape is similar to sheet pile profiles, increases the rigidity of Plastic Sheet Pile and supports the weight of the driving equipment such as a vibro-hammer.

What is the proper machine to drive piles in different conditions?

Impact driving is suitable for all soil types but appears to create the highest degree of stress to sheet piles. It is more appropriate to cohesive soils and soft soils such as silts and peats, loose medium to coarse sand, and gravels free of rock inclusions. Drop hammers such as the hydraulic hammer are the common types of impact-driving machinery. Driving using vibratory hammers is ideal for non-cohesive or granular soils such as soft soils and round-grained sand or gravel. It has also shown satisfactory performance in sandy, silty, or softer clay soils. It is less effective in angular-grained materials and soils with a firm consistency. With the introduction of vibration, however, the sub-soil can be further compacted, increasing penetration resistance and ultimately-refusal. If this is the case, driving aids like jetting and drilling might be necessary.

What are the pvc sheet pile selection criteria for soil condition of different hardness?

General rule of the thumb: “the harder the soil, the stronger and stiffer sheet pile section should be used”. Driveability of a pile section is a consequence of its cross-sectional properties (thickness, depth, and width), designed shape, length, grade, and the applied load. Hardness of soil strata characterized by SPT or CPT values is used to predict soil resistance which is essential in the calculation of driving force to be applied. Knowing the range of force from the selected driving machine, corresponding sheet pile sections can be picked according to their yield strength and elastic modulus.

How should I choose a sheet pile section for soils with, say, SPT Value, N=30? Can I still consider using vinyl or shift to steel?

Every sheet pile material has a design purpose, strengths, and areas of improvement. The availability of different materials denotes the need for a special material for a specific application. Plastic or synthetic sheet piles for example are known for being light and corrosion-resistant; Steel sheet piles are recognized for their extraordinary strength and versatility; and so on.

Construction and Excavation Safety: How to Choose the Right Trench Shield Supplier

ESC Steel LLC
Aug 23, 2022
3 min read

Updated: Jun 22

Trenches are present in almost all earthworks, such as foundation excavation, underground utilities installation, irrigation, and more. Unfortunately, statistic says that about 80% of excavation deaths occur in the construction industry due to trench collapses.

As a consequence, the use of trench protection has become a mandatory requirement. Whether it is a minor cable installation job, household pipelaying, or a massive excavation work for building a foundation, a certified trench shield or trench shoring system must be in place when required by the criteria stated in the OSHA Manual.

As of today, the global market offers many trench protection products to choose from, all of which are compliant with OSHA requirements and other standards in excavation safety. The thing now is how to shortlist or pick the most efficient type of protection according to the conditions of your excavation and trenching project.

This brief guide will help you identify your trusted manufacturer and select the ideal product for your needs.

Trench Shields: Construction Safety Essentials

A trench shield, also known as a trench box, should always be made of high-grade steel or aluminum. These shields will be lining the sides of an excavation site to protect workers inside the trenches. Therefore, the material should have enough integrity to prevent cave-ins or collapses.

Trench shields consist of two modular panels on either side. Between these panels, you will have struts or spreaders of adjustable length. The function of these spreaders is to hold the panels in place from either side along the site's walls.

A quality trench shield manufacturer should offer a variety of dimensions and capacities in their panels and spreaders. They should also be able to guarantee that their shields strictly comply with the requirements of OSHA standards. This ensures that employees within the trench will be protected from hazards.

Trench Shield Installation Parameters

Before installing trench shields, there are a few details that must be established. Firstly, the purpose of your excavation project determines what size trench you need. Obviously, large pipes and thin wires require different sizes of trenches. There's no use in building a larger trench than is necessary. The right trench shields supplier should be able to accommodate your specific project.

Depth of the required excavation and the easement of the surrounding area are also very important factors to consider when deciding the extent and type of trench protection to choose. Sloping or benching of trench sides combined with a shield at the trench bottom is allowed as long as the conditions in the OSHA standards are met. This can substantially reduce the expenses in purchasing or renting trench boxes, but of course, this is only possible in open areas without nearby buildings or structures.

Furthermore, you should also be wary of obstructions in the path of your planned trench. A knowledgeable trench shield manufacturer should assist in avoiding or clearing these obstructions.

Even knowledge of what type of soil you plan on excavating in will prove a crucial detail. This will affect what excavation equipment your project will need. OSHA classifies soil as Stable Rock, Type A, Type B, and Type C. Knowing the soil classification at the project site is essential in determining the ratings of the trench shield to employ.

The capacity of the lifting equipment is also a contributing factor to the choice of box or shield. Project sites with cranes have nothing to worry about and can pick any size and weight of box or shield. But most sites usually utilize excavators to install a shoring or shielding system, wherein safe lifting capacities are strictly observed. In the worst scenario, where using any lifting equipment is impossible due to space limitations, shielding or shoring systems that are site-assembled or fabricated are mandatory.

OSHA-trained competent person must also inspect your site for other potential hazards. You will want a trench shield supplier that can assist you at every step of the process.

Don't Wait to Put Your Construction Project In the Best Hands

Construction safety is no place where you can afford to take the easy route. Trench work bears too many risks not to proceed with maximum research and caution.

At ESC Trench, we offer a variety of trench shields guaranteed to last. Whether you're looking to buy or rent, our trench boxes comply with all OSHA standards.

Want to know how our trench shields can meet the needs of your unique excavation project? Contact us today and let us show you how we bring maximum safety to your site.