vibrohammer

A vibrohammer, also known as a vibratory hammer, is a type of pile driver that uses high-frequency vibrations to install piles into soil or to extract them. The hammer mounts on a crane or pile-setting rig and transmits controlled vibratory energy to the pile through a clamping system. The vibration is produced by an eccentric weighted rotor driven by a hydraulic or electric motor, with adjustable frequency and amplitude to suit soil conditions. As the pile vibrates, soil grains temporarily lose friction and interlock, allowing the pile to advance with less driving force than a traditional impact hammer.

How it works: The vibrating action reduces soil shear strength around the pile and temporarily increases pore pressure, causing a reduction in resistance to penetration. The pile is advanced while the machine maintains appropriate vibration; once the desired depth is reached or the soil returns to its normal state, the vibration is reduced or stopped to set the pile in place. In some cases, controlled extraction is achieved by reversing the vibration direction or using auxiliary equipment.

Types and use: The main categories are hydraulic and electric vibrohammers. They are widely used for driving steel piles, H-piles, and sheet piles, particularly in marine construction, river and coastal works, and urban foundations where quiet operation and reduced ground vibration are advantageous. They are often preferred in sandy or loose soils but may be less effective in dense gravel, clay seams, or rocky strata.

Limitations: Vibrohammers may be unsuitable for very hard soils or near sensitive structures, and they can cause unwanted ground movements or vibrational impacts if not properly controlled. Proper zoning, monitoring, and soil assessment are essential for safe, effective use.