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.

- Jul 14, 2021
- 2 min read

ESC Trench Shields Solutions

Updated: Aug 28, 2021

ESC’s world-wide acclamation is sustained by its experience and product contribution in excavation and trench safety. The range of products that includes sheet piles, tubular piles, struts, trench shields/boxes, and tie-rod systems exhibits an undisputed level of commitment to system development and perfection.

ESC is devoted to continual exploration of the versatility and possible combinations of these solutions that may lead to more effective, safe, and time saving project executions.

Global Challenge

Construction projects keeps coming in larger and more complex packages and with intensified statutory restrictions. Timetables however are not becoming flexible but instead are constantly compressed in efforts to reduce costs.

These constraints create conflict and heighten the challenge of maintaining a safe but productive working environment.

How can you build Better, Safer and Faster?

This question was on the table when Kevin Ashdown – Managing Director of ESC Group Middle East, founded and led the Design Development Team of the ESC Heavy Duty Trench Shield in 2015.

The next year (2016), the first unit of the proprietary Trench Shields - designed to International Standards EN 13331-1 & 2 - was produced in ESC’s 400,000 square feet manufacturing facility in Abu Dhabi, UAE. A third party engineering company was commissioned to test and certify the boxes. This included full scale destructive testing, and intensive three dimensional finite element modelling, after which the designs were endorsed and certificates for each of the shields were issued.

Following the initial launch, the first batch of shields was provided free of charge to local contractors, and the development team worked closely with the contractors to monitor product performance and customer feedback. This feedback was then used to make improvements to the designs and then full production started. Continuous improvement has been ongoing ever since. In 2018, adjustable strut (or spreader) system were introduced as an addition to the fixed strut system.

The manually adjustable strut is designed to provide a width matrix of close increments that corresponds to actual trench widths and shapes. Subsequently, Manhole Trench Shield/Trench Box were developed in 2019 in response to unceasing pipeline network projects. Manhole Trench Shields are used in conjunction with regular trench shields and acts as a transition piece that provides a wider section shoring to accommodate the presence of a manhole, basin, or pit.

Going worldwide in the same year-2019, ESC Trench Shoring, Inc. developed a version of these Trench Shields in the U.S.A. with emphasis on compliance to Safety Specifications such as OSHA 29 CFR 1926.650, 29 CFR 1926.651 and CFR 1926.652, Subpart P. The US product range is specifically designed to cater for the unique requirements of the US market and construction practices.

As with the original shields, the US range has been verified and certified by a third party professional engineer in the USA. And in the early 2020, ESC has obtained qualification and became a member of NAXSA (North American Excavation Shoring

Association).

To date, ESC Group Middle East has produced 900 shields. Nearly 300 of these are maintained in ESC’s extensive rental fleet and the balance have been sold to local contractors and throughout the GCC. However, with ESC’s venture in North America, the real extent of the product’s success is yet to be measured.