Brief Introduction to Piling Barge: Structure, Classification and Construction Technology

Piling Barges，Brief Introduction to the Structure, Classification and Construction Technology

A piling barge is an engineering vessel used for offshore construction such as pile driving and pile extraction for hydraulic structures. It can also be used as a crane vessel for lifting cargoes, installing components and equipment. It is widely used in the construction of bridges, wharves and water conservancy projects.

Piling barges are usually named by the height of the piling frame(pile leader). The hull is of steel box structure, with a piling frame installed at the end of the deck, which can tilt forward and backward to meet the needs of driving inclined piles. Most piling barges are non-self-propelled and need to be towed into position by tugboats.

1 Classification of Piling Barges

1.1 Classification by Piling Frame Type

Luffing Frame Piling Barge: The piling frame adopts a triangular truss structure, and can tilt through hydraulic cylinders to drive vertical and inclined piles.

Rotating Frame Piling Barge: The frame can not only tilt but also rotate horizontally, suitable for intensive pile group construction.

Hatch-Type Piling Barge: Adaptable to various tilting angles, used in shallow water, shoreline areas or pile replacement in pile groups where positioning is difficult.

Swinging Frame Piling Barge: The frame can tilt forward/backward and swing left/right.

Platform-Type Piling Barge: Multi-functional for tilting piling, hatch-type piling and jacket-fixed positioning. It has strong wind resistance but is greatly affected by seabed terrain and soil conditions.

1.2 Classification by Marine Power Plant

Power Station Type Piling Barge: Powered by diesel generator sets, electric motors drive various mechanical equipment for ship maneuvering and piling construction.

Hydraulic Pump Station Type Piling Barge: A diesel engine directly drives a hydraulic oil pump, and hydraulic transmission is used for ship maneuvering and piling construction.

1.3 Classification by Piling Frame Height

Small Piling Barge: below 50m

Medium Piling Barge: 50m to 80m

Large Piling Barge: above 80m

2 Main Equipment and Performance of Piling Barges

The main equipment of a piling barge includes piling equipment, deck equipment and power plants.

2.1 Piling Equipment

Including piling frames and equipped pile hammers, backboards, pile grippers, lifting hooks, etc. They determine key performance indicators such as construction performance, operation efficiency and working area.

2.2 Deck Equipment

Including piling frame luffing mechanisms, ship-moving winches, lifting winches, etc.

2.3 Power Plant

The power plant of electric piling barges mainly includes main generators, stationary generators, various water pumps and air compressors. The main generator supplies power for the ship’s construction machinery (ship-moving winches, lifting winches, luffing cylinders and other auxiliary equipment).The main power plant of hydraulic pump station type piling barges is an oil pump diesel engine and an auxiliary generator. The oil pump diesel engine directly drives the hydraulic power station through a high-elastic friction clutch and a gear transfer case to provide power for the ship’s power equipment. The auxiliary generator supplies power for various water pumps and air compressors.

3 Technical Status and Development Trend of Offshore Engineering Piling Barges

Pile foundation is the foundation of offshore engineering facilities. Installation accuracy and piling depth are important factors affecting the safety and operation of offshore engineering facilities.

There are five main types of offshore wind turbine foundation piles: high-pile cap, single pile foundation, jacket foundation, suction bucket foundation and gravity foundation. The factors influencing the selection of offshore wind turbine foundation structure mainly include water depth, seabed conditions, external loads, construction methods, site conditions and costs.

3.1 Single Pile Foundation

Structural Features: Large-diameter single pile with large size and weight.Main Technology: Pile transportation, ship moving and pile hoisting, self-sinking and deviation correction, hammer driving pile, inspection and acceptance, pile clamping, etc.Piling Equipment Selection: Guide frame + floating crane.Application Scope: Sea areas of 5m~20m.Existing Problems: Short effective operating time in unlimited navigation areas, difficult construction of super-long large-diameter inclined piles, and high requirements for piling barge performance.

3.2 High-Pile Cap Foundation

Structural Features: Usually composed of 6 to 8 inclined piles, capable of bearing lateral force and strong anti-slip ability.Main Technology: Pile foundation construction, fabrication and installation of auxiliary components, and other foundation structure construction.Piling Equipment Selection: Mobile platform piling system (special piling barge).Application Scope: Both shallow and deep water, generally for steel pipe piles with a diameter less than 5m.Existing Problems: Relatively long pile foundation and heavy overall structure.

3.3 Jacket Foundation

Structural Features: High strength, light weight and small deformation under ocean current action.Main Technology: Fabrication and transportation of steel pipe piles and jackets, steel pipe pile sinking, jacket installation, grouting construction, and installation of auxiliary facilities.Piling Equipment Selection: Floating crane + positioning guide frame.Application Scope: Deep sea areas of 20m~60m.Existing Problems: Many pile connection processes (cutting, assembly, welding and inspection), which are complicated.

Steel Pipe Pile Sinking Construction Technology

Piling barge positioning → Pile carrier berthing → Pile body marking → Ship moving and positioning → Rough positioning → Pile erecting into hatch → Closing pile gripper → Precise measurement and positioning → Ship moving, cable tightening and hoisting → Pile self-sinking / fine-tuning → Releasing sling / pressing hammer → Opening pile gripper and hammering → Lifting / re-hammering → Next pile

4 Development Trend of Piling Barges

With the rapid development of offshore engineering construction, piling barges, as professional engineering vessels, have developed from small and single-function to ultra-large and multi-functional vessels. Since the 21st century, China has successfully joined the ranks of piling barge construction, breaking the monopoly of ultra-large special piling barge construction technology by Europe, America, Japan and South Korea.

The large-scale development of piling barges has complicated the stress of the piling frame structure and hydraulic actuators. Considering the dynamic loads under complex working conditions such as wind force, piling operation and ship motion attitude, establishing a coupling system model for motion response simulation and verification of the piling frame and constant power matching has become an essential design method for the piling frame structure and hydraulic actuator system of piling barges. With the vigorous development of the marine economy, ultra-large special piling barges with high stability, high positioning accuracy and environmental friendliness will develop rapidly to meet the needs of ultra-large pile diameter, pile depth, pile grouping / replacement and other piling operations.

5 Application of Hydraulic Piling Hammers in Harbor Foundation Pile Engineering

5.1 Demand for Large-Scale Foundation Pile Engineering

Harbor engineering is increasingly developing towards deep water and large scale, and the section of engineering foundation piles is gradually increasing. 0.7m×0.7m reinforced concrete square piles, concrete pipe piles with a diameter of 1.2~1.4m and steel pipe piles with a diameter of 1.2~2.5m have been adopted. It is expected that the vertical ultimate bearing capacity of a single foundation pile will reach 15000~20000kN or even more than 20000kN in the future. In addition, to meet the design requirements of elastic long piles, it is necessary to penetrate soil layers with high standard penetration values to achieve a large penetration depth. The existing large diesel hammer D100-13 is difficult to drive such large-section, large-diameter and high-bearing capacity long piles.Domestic data over the years show that the ultimate bearing capacity of foundation piles driven by D100-13 diesel hammer is 6000~12000kN, with a maximum pile length of about 60m, which is far from the demand. Therefore, it is of great practical significance to select larger pile hammers for mega-foundation pile projects such as Shanghai Yangshan Deepwater Port, East China Sea Bridge and Hangzhou Bay Bridge.

5.2 Development of Large‑Scale Pile Hammers

Large‑scale pile hammers mainly include three types: steam hammers, diesel hammers, and hydraulic hammers.

Steam hammers were gradually replaced by diesel hammers in the 1950s due to their complex system. In the 1970s, steam hammers were upgraded in technology and structure while retaining their advantages, significantly improving impact energy. With a ram weight of 260–2600 kN, a maximum stroke of approximately 1.5 m, rated impact energy of 208–2500 kN·m, and a total weight of 383–3861 kN, steam hammers once led the market of large‑scale piling hammers and were widely used for offshore oil platform foundations.

Since the 1980s, hydraulic piling hammers have been developed with the advancement of hydraulic technology. They are lightweight, highly efficient, stable, low‑noise, low‑emission, and suitable for underwater piling. Their impact energy is comparable to large steam hammers, and they have completely replaced steam hammers.

The further upscaling of diesel hammers is restricted by an unavoidable overheating problem. Similar to a single‑cylinder diesel engine, a diesel hammer relies on compression‑ignition combustion to drive the ram. Larger size means higher thermal parameters, greater thermal load, and increased thermal and mechanical stress, leading to severe overheating.

Overheating causes premature fuel combustion before impact, reducing striking force. The performance decline worsens as piling time and anvil temperature increase. Cooldown is often required, and no reliable cooling solution exists. In addition, diesel hammers generate high noise and exhaust pollution, worsening working conditions. These drawbacks make diesel hammers unsuitable for large‑scale applications.

Hydraulic hammers are produced by manufacturers in China, Japan, Germany, Finland, the Netherlands, the UK, and other countries. Typical large models include:

B.S.P HH60 (UK): 720 kN·m
MHU‑1700T (Germany): 1700 kN·m, total weight 2600 kN
Junttan HHK365 (Finland): 540 kN·m, weight 550 kN
HIBM 3000 / HBM 5000 (Netherlands): 600 kN·m and 1000 kN·m

International manufacturers can design and build large hydraulic hammers to meet various project requirements.

5.3 Effective Energy Comparison of Hydraulic Pile Hammers

The selection of pile hammers should fully consider factors such as pile type, pile weight, penetration depth, geological distribution of the piling area and standard penetration value N of each soil layer at the pile tip, based on the performance of various pile hammers. In short, the kinetic energy of the selected hammer must sufficiently exceed the pile driving resistance, including pile tip resistance, lateral friction resistance and energy loss caused by elastic work. More importantly, the effective energy transmitted by hammering is the decisive factor for pile penetration, so the effective energy of the pile hammer is the primary consideration in selection.

Hydraulic hammers are divided into single-acting and double-acting types. The single-acting hydraulic hammer is lifted by hydraulic power and falls by gravity to strike the hammer pad; the double-acting hydraulic hammer moves the hammer head up and down by hydraulic power, with a fully enclosed hammer body. The hammer core is hydraulically accelerated to free fall when falling, delivering greater energy to strike the hammer pad.Driven by a diesel engine, the hydraulic hammer is equipped with a special steel hammer pad to effectively transmit kinetic energy with durability. The hammer pad is usually made of disposable cast MC901 with long service life and easy replacement, which has considerable elasticity and extremely high impact energy transfer efficiency, and is a patent of various companies.

Different from diesel hammers, the continuous operation of the diesel hammer core depends on the combustion and explosion process of diesel oil, which is realized based on the reaction force of the foundation to the hammer core through the pile. The impact energy is determined by the reaction force to a certain extent, not by the operator. Hydraulic hammers can be freely controlled and equipped with low-noise devices to meet environmental protection requirements.

The calculation of pile hammer energy varies with hammer types. Single-acting hammers are usually expressed by rated hammering energy, equal to the product of the hammer head weight W and the maximum drop distance H (ER=WH); double-acting hammers are generally expressed by "net piling energy", related to the hammer head mass and the instantaneous speed of the impact body, calculated by the formula EA=1/2mv². For concrete piles, the instantaneous impact speed v ≤ 4.5m/s to avoid pile damage; for steel piles, v can be increased to 6.0m/s.

When using double-acting hammers for concrete piles, the drop height must be strictly limited to keep v ≤ 4.5m/s, and the kinetic energy is generally reduced to less than 65%. Single-acting hydraulic hammers are suitable for concrete piles, and double-acting hydraulic hammers are suitable for steel pipe piles. Low drop, low speed, heavy hammer and light hammering have great advantages in pile penetration and pile top integrity.

The falling speed of the hydraulic hammer core is equivalent to free fall, because the hydraulic energy to overcome friction loss during falling does not produce any resistance. However, affected by hammer pads and pile pads, the effective energy transmitted to the pile body needs to be multiplied by a reduction factor (effective energy transfer coefficient) for both hydraulic and diesel hammers.Test results show that the effective energy transfer coefficient of hydraulic hammers is 1.6~2.2 times higher than that of diesel hammers. The actual energy transmitted to the pile body by diesel hammers is 20%~30% of the rated energy, while that of hydraulic hammers can reach 45%~48%. Generally, the energy transfer rate is 25%~45% for diesel hammers and 60%~85% for hydraulic hammers.

Tests show that the kinetic energy transfer efficiency of all hydraulic hammers is much higher than that of diesel hammers, with the overall average value more than twice that of diesel hammers.

5.4 Conclusion and Suggestions

Although diesel hammers are widely used in China with mature technology, they obviously have disadvantages such as high pollution, high noise, difficult control, easy damage to concrete piles, low energy transfer rate and frequent maintenance.

Hydraulic hammers are a new generation of environmentally friendly mainstream equipment with low pollution, low noise, accurate control, high energy transfer and stable construction quality. They are suitable for popularization and application in large-scale foundation pile projects such as ports, bridges and offshore wind farms.

FAQs for Piling Barge & Pile Hammer

Q: What is a piling barge mainly used for?

A piling barge is a special engineering vessel used for pile driving and pile extracting in waterborne construction. It is widely applied in bridges, wharves, water conservancy projects, and offshore wind farm foundation installation.

Q:How are piling barges classified?

Piling barges are classified by three criteria: piling frame type (luffing, rotating, platform, etc.), power system (electrical or hydraulic), and piling frame height (small: below 50m; medium: 50–80m; large: above 80m).

Q:Why are hydraulic piling hammers better than diesel hammers?

Hydraulic hammers have higher energy efficiency, lower noise, less pollution, and stable performance. They avoid overheating issues and achieve an energy transfer rate of 60%–85%, much higher than diesel hammers, making them ideal for large-scale pile projects.