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.

Marine Mooring Bollard Maintenance Tips to Follow

Marine mooring bollards are vital equipment for all marinas and harbors. They provide a secure point of contact to connect the mooring lines of vessels to the jetties or wharves of the port.

Each mooring bollard must be capable of withstanding the tremendous forces that large vessels exert on them. They must be manufactured from high-strength materials to guarantee durable performance.

ESC mooring bollards are engineered accurately and manufactured in ductile cast iron or steel supplied with high-quality galvanized anchor bolts to offer our clients maximum resistance to berthing impact.

When looking for a marine mooring bollard supplier, the client must provide vital information about your project to a trusted supplier who understands the required International Standards and regulations, the level of support needed by your port, and all the other details associated with bollard production.

Once you have these bollards installed on your dockyards, it's also important to have an inspection and maintenance schedule in place as an essential safety feature and optimal performance.

In this guide, we'll explain how to inspect and maintain mooring bollards to ensure they remain within their designed strength parameters.

What Are Mooring Bollards?

There are many types of mooring bollards; ESC has a wide range of options to ensure we provide solutions to every application, each type suitable for different uses and loads. Mooring bollards are a vital component of any mooring system. It is the anchor point for mooring lines mounted on the deck to secure the ship or vessel.

No matter the bollard's design, they all serve the same purpose. That is to attach the mooring wires - or lines - of a vessel to the harbor quay. Depending on the design profile, they can accommodate one or more mooring lines.

installation and maintenance of mooring bollards

There are various types of marine bollards, including t-head, t-horn, kidney-shaped bollards, cleat, single-bitt bollards, double-bitt bollards, pillar bollards, tricorn bollards, T-head Japanese and Pillar Japanese bollards.

Most common bollards have a hook or T-shape to prevent the ropes from slipping off. This is particularly important for harbors with a sizeable tidal variation. As the vessel moves, it changes the angle of the mooring line and requires a specialized bollard like the T-Horn to keep a secure connection. To find out more about mooring bollards type and applications click here.

To ensure the safety and efficient performance of the mooring bollards, you need to guarantee that they are in good working condition to use in daily mooring operations.

Due to their exposure to seawater, they are at high risk of corrosion which can significantly affect their service life. It is crucial to perform routine maintenance to extend the service life and reduce the possible damages to the installed mooring bollards.

How to Clean and Maintain a Mooring Bollard?

Bollards are constantly exposed to the elements and the corrosive effect of sea splashes.

Although they are low-maintenance equipment, it's essential to conduct periodic inspections. These should include examining the following:

Surface inspection for scratches/damage to paint and corrosion of the material.
Compare barrel thickness with manufacturer specifications
Check with a torque wrench that all the anchor bolts are sufficiently tight
Ensure anchor bolts are adequately coated and corrosion free
Inspect grout under bollard and replace if necessary

A quarterly assessment should be performed in cases with recognizable irregular behaviors. A relevant corrective action should be taken to maintain its required performance.

Any chips or cracks in the paint should be repaired immediately to prevent corrosion from forming. Cast steel is particularly susceptible to corrosion. It needs regular repainting as per the manufacturer's specifications.

How to Reinforce Mooring Bollards?

Daily pulling of the mooring bollards may result in possible loosening.

Bollards are generally attached to the surface of a quay with galvanized bolts and grout. In some cases, the bolts are secured on the undersurface with a through bolting system. This provides a stronger connection than surface-mounted bollards.

For extra reinforcement, a base plate is sometimes used to provide additional support. These improve the strength rating of deck-mounted bollards on vessels. It is necessary to pay attention to the support conditions and the regular examination for the tightness, guaranteeing strength.

Are You Looking for a Marine Mooring Bollard Supplier?

A mooring bollard is essential to every harbor and ship docking facility. If you're looking for an industry leader in the production of bollards, then contact ESC Marine Systems.

We have over 30 years of experience supplying high-quality bollards to many customers. Our manufacturing facilities are strategically located worldwide to provide you with superior service.