What is a Vibro Hammer?
Also known as a vibratory hammer, a vibro hammer is a construction equipment used to drive or extract piles by applying vibrations. It operates by transmitting high-frequency vibration energy to the pile, which causes the surrounding soil particles to loosen and reduces resistance to pile penetration.
Vibratory pile driving machines are widely used in construction projects such as ports, bridges, marine structures, offshore wind farms, airports, roads, railways, infrastructure works, solar energy, wind turbines, retaining walls, and many other foundation applications. Vibratory hammers are modern and popular machines for driving pipe, sheet, and timber piles. Therefore, they are frequently preferred in urban areas and city centers.
There are various types of vibratory hammers, including pile-mounted vibratory hammers, crane-suspended vibratory hammers, and variable moment vibratory hammers. The selection of the appropriate type depends on the size and weight of the pile as well as the soil conditions on site.
Modern pile driving machines are quieter and offer many advantages compared to traditional pile driving methods that rely on heavy impact. One of the biggest advantages of vibratory hammers is their ability to drive and extract piles much faster. In addition, they are compact, significantly quieter, and environmentally friendly. They can be used underwater, remove existing piles, and operate near residential areas without causing noise disturbance. Their lightweight structure also makes transportation easier. Furthermore, in some vibratory hammers, vibration can be fully controlled, which is essential when working in urban or historically sensitive areas.
You can learn more about Vibratory Hammers, What is a Vibro Hammer?, and Types of Pile Driving Machines.
How Does a Vibratory Hammer Work?
OMS vibratory pile driving machines, also known as vibratory drivers or vibratory hammers, operate by reducing soil resistance through vibration and altering the soil structure. The vibratory pile driving machine transmits vertical vibrations to the pile via a hydraulic clamp. This transfers vibration into the ground, reducing friction between the pile and the soil, allowing the pile to be driven or extracted with less force. The pile is driven into the ground through the combined effect of the vibrator’s weight and the centrifugal force it generates.
If you are interested in ground improvement, you can read articles on the installation of top-feed and bottom-feed vibro flotation systems, wick drain systems, and stone column equipment, as well as learn more about Ground Improvement Techniques.
How Does a Crane-Suspended Vibratory Hammer Work? Animation Video
Operating System of an Excavator-Mounted Vibratory Hammer
Types of Vibratory Hammers
Crane-Suspended Vibratory Hammers
Excavator-Mounted Vibratory Hammers
Side-Grip Vibratory Sheet Pile Drivers
What Are the Advantages of Vibratory Hammers?
- Vibratory hammers drive piles faster, saving both time and costs.
- They can be used for both driving and extracting piles.
- They can be used underwater.
- They are lightweight and easy to operate.
- They can be used with both cranes and excavators, depending on the application.
- For projects requiring high lifting/lowering capacity, crane-suspended vibratory hammers powered by dedicated power units are used.
- They feature environmentally friendly technology (especially for protecting wildlife).
- They can be powered by hydraulic or electric systems; however, hydraulic systems are generally preferred due to being lighter and more powerful.
- They are compact, easy to transport, and simple to maintain.
- Compared to conventional impact pile driving machines, vibratory pile driving machines are significantly more economical.
Eccentric Moment M (kgm):
Eccentric moment is calculated based on the eccentric mass (m) and the distance (r) of the center of gravity from the axis of rotation.
Centrifugal Force F (kN):
F = 0,011 · n² · 10⁻³ · M
n: Rotational speed of the hydraulic motor (rpm)
Amplitude A (mm):
Amplitude is the total vertical displacement of the vibration device during one full rotation of the eccentric weights.
The amplitude at maximum rotational speed is calculated using the following formula:
A = (2 · M / m₍d₎) × 1000
Amplitude Formula
M = Eccentric Moment (kgm)
m₍d₎ = Dynamic Weight
Dynamic Weight:
Dynamic weight is the total weight of the vibrator, hydraulic clamp, and the pile to be driven.
Operating Principle of Vibratory Pile Driving Machines
Operating Principle of Resonance-Free Vibratory Hammers
The OMS-patented “Phase Shifting Motor” enables adjustment of vibration levels by controlling the movement of eccentric masses. The eccentric masses can be adjusted between 0° and 180°. Maximum vibration level is achieved at 180°.
Balanced Eccentric Masses
The phase shifter brings the eccentric masses into a balanced position via remote control or a control panel, preventing resonance.
Eccentric Masses Transitioning from Unbalanced to Unbalanced State
The phase shifter adjusts the position of the eccentric masses from 0° to 180° to enable the vibratory pile driving machine to operate at maximum amplitude.
Eccentric Masses in Unbalanced State
180° Full Power
Operating Principle of Excavator-Mounted Vibratory Drivers
Connect the pressure and return line hoses coming from the excavator to the flow meter. Ensure that the hoses are correctly connected to the appropriate ports of the flow meter.Adjust the pressure of the flow meter using the limiter according to the required pressure for your vibratory machine, and regulate the necessary flow using the main pump control valve of the excavator.
Install a flow meter between the Pressure (P) and Return (R) line hoses of the excavator and the vibrator. Adjust the required pressure and flow using the main pump control valve of the excavator.The Drain (D) pressure must not exceed 8 bar. If the drain pressure exceeds 8 bar, the relief valve in the drain line will reduce the pressure to prevent damage to the hydraulic motor shaft seal.
Connect the pressure and return line hoses coming from the excavator to the flow meter. Ensure that the hoses are properly connected to the correct ports of the flow meter.Adjust the pressure of the flow meter using the limiter according to the required pressure for your vibratory machine, and regulate the required flow using the main pump control valve of the excavator.
8 Steps to Install a Vibratory Driver on an Excavator
- Move the excavator to the location where the vibrator is positioned. Lift the vibrator and securely support it in a vertical position.
- Ensure that the ears of the connection bracket are properly seated on the excavator arm at the bucket pivot area.
- Check that the connection pin is fully seated in the bucket pivot hole.
- If all connections are correct, attach the connection bracket to the excavator arm.
- Fully retract the bucket cylinder and turn off the excavator.
- Disconnect the hoses of the bucket cylinder and seal them with a plug of appropriate size.
- Remove the plugs (P, R, and D) from the manifold and connect and tighten the excavator hoses to the vibrator. Refer to the image below for guidance.
- To release the air inside the hoses, loosen the hoses from the clamp cylinder (approximately one turn). Start the excavator at low speed and gently move the joystick to close the clamp. Wait until oil flows from the connection at the clamp. Once oil flows without air, tighten the connection.
Required Pressure (P) and Flow Rate (Q)
| VIBRATORY HAMMER | P (BAR) Q | (LPM) |
|---|---|---|
| OVR 20 S | 280 – 320 | 62 |
| OVR 40 S | 280 – 320 | 100 |
| OVR 50 S | 280 – 320 | 150 |
| OVR 60 S | 280 – 320 | 201 |
| OVR 70 S | 280 – 320 | 233 |
| OVR 80 S | 280 – 320 | 275 |
| OVR 120 S | 280 – 320 | 313 |
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