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.

ESC Group

Dec 10, 20234 min read

Mooring Bollard: Ensuring Ship Safety with Strategic Use

Updated: Feb 24

A mooring bollard functions as a vital fixture in maritime transportation and shipping, employed to safely fasten ships and boats to a dock or quay. Serving as a secure anchor point, mooring bollards play a crucial role in the mooring process. Mooring lines, comprising ropes or cables, are attached to the vessel and secured to these bollards.

This setup ensures that the ship remains firmly in place while berthed, preventing unwanted movement and ensuring stability during docking operations. Mooring bollards are fixed on the deck or pier, preventing unintended movement, facilitating efficient loading and unloading operations, and their design varies to accommodate different mooring requirements.

Crafting mooring bollards involves either metal casting or welding, and their structural design is crucial to withstand the forces applied by mooring lines. Various mooring bollard types and styles are available, each customized for specific applications and vessel dimensions.

Marine mooring bollards that are appropriately designed, installed, and properly maintained contributes to safe, efficient, and dependable vessel mooring and to mitigate the risks associated with improper use or not utilizing mooring bollards such as the following:

Confusion and Danger - An unclear mooring area without proper equipment can create confusion and pose danger. Unused ropes and equipment may lead to hazards, especially in areas with a higher degree of risk
Corrosion and Maintenance Issues: Mooring bollards, when not used, are exposed to seawater, increasing the risk of corrosion. Neglecting their use may result in maintenance issues, affecting the service life of the bollards.
Overloading Risks: Deviating from proper mooring practices, such as overloading bollards with multiple mooring lines, can lead to specific risks. Overloading may compromise the structural integrity of the bollards, posing a threat to safety.
Fatal Accidents: Mooring accidents, including fatal incidents, have been recorded due to poor mooring practices.
Snap Back Accidents: One of the significant dangers in mooring operations is the risk of snap-back accidents, where the failure of ropes or wires can lead to sudden and hazardous movements.

The mentioned risks emphasize the importance of safety considerations. Utilizing mooring bollards will definitely provide numerous benefits in maritime operations, here are some:

Secure Docking: Mooring bollards provide secure points for ships and boats to dock, preventing them from drifting or moving accidentally during loading, unloading, or while stationary at a quay or dock.
Preventing Accidents: The use of mooring bollards helps prevent accidents by ensuring vessels are securely anchored. This is essential in busy ports and harbors where precise control over a vessel's position is crucial for safety
Stability and Control: Bollards act as fixed points to which mooring lines or ropes are attached, providing stability and control over the vessel's movement. This is especially important in adverse weather conditions or strong currents.
Structural Integrity: Mooring bollards are designed to engage with the bottom quickly, generating a grasping force that enhances their structural integrity. This ensures their effectiveness in holding vessels securely.
Urban Planning and Safety: Beyond maritime use, bollards play a critical role in urban planning, serving as protective barriers to prevent accidents and potential harm. Safety bollards contribute to creating safer environments in various settings.
Aesthetics and Functionality: While some bollards serve aesthetic purposes, mooring bollards at docks and ports are primarily functional, ensuring the safe and efficient operation of maritime activities

There are standards established for utilizing mooring bollards in maritime applications. Compliance with these standards is crucial to ensure the safety, efficiency, and reliability of mooring systems. ISO 13797:2020 is a standard in the field of ships and marine technology. It specifies the types, nominal sizes, dimensions, materials, and construction requirements for bollards used in mooring and towing operations on sea-going vessels.

The document outlines the manufacturing and marking requirements for these bollards, providing a comprehensive guide for their design and use in the maritime industry. The standard aims to ensure consistency and safety in the construction and implementation of bollards.

Proper installation of mooring bollards is essential for ensuring a prolonged and trouble-free lifespan. Accurate installation of anchor bolts using a bolted template formwork is crucial. After the grout attains maximum strength, anchor bolts can be securely tightened to the designed preload. Adhesives are frequently applied around exposed threads to simplify future removal. Whenever feasible, embedding the bollard in concrete offers more advantages than surface mounting.

Over time, the mechanical efficiency of bollards can decline. It is imperative to conduct durability tests and consistently inspect them to ensure optimal functionality and identify any maintenance requirements.

Thoughtful considerations in following standards for mooring bollards include:

Proper Training: Users should receive adequate training in the safe use of mooring bollards to minimize risks.
Choosing the Right Bollards: Consideration of boat length and reliable suppliers is advised when selecting mooring bollards.
Variety of Design Profiles: Bollards are available in a range of design profiles, sizes, and capacities to suit different mooring system applications.
Testing: Regular testing is essential to establish the adequacy of mooring facilities and enable efficient berthing plans.
Compliance with Industry Standards: Ensure that mooring bollards comply with relevant industry standards and regulations

When selecting a bollard system, it's crucial to choose a trustworthy supplier. ESC Marine Systems ensures the highest quality with bollards crafted in adherence to global standards like BS 6349 pt 4 and PIANC guidelines. Recognizing the pivotal role of bollards as safety-critical components, ESC is dedicated to delivering products with extended service life and robust resilience against both physical and corrosive challenges.

Different bollard types are offered and produced to the highest specification and also options for customization is also available.

Safeguarding product excellence, ESC also assist in assurance testing and quality documentation package may include:

Dimensioned drawings of bollard and accessories
Bollard and anchorage calculations (if required)
Inspection and test plan
Certificate of conformance
Physical, chemical and material properties report for casting and anchorages
Installation guidelines

Throughout the time, mooring bollards have played a crucial role in the maritime industry, adapting to the evolving needs of the field. Essential for securing vessels to docks, quays, and piers, they ensure safe and efficient maritime operations.

ESC Marine Systems comprehends the vital role of mooring bollards and remains committed to delivering a diverse range of high-quality cast iron and steel bollards tailored to meet the requirements of various mooring system applications.