Vibrohammers

A vibrohammer (also vibratory hammer or vibro-driver) is a machine used in foundation and marine construction to install or extract driven piles and sheet piles by applying high-frequency oscillatory forces. It reduces soil resistance around the pile by fluidizing or loosening soil particles, allowing the element to sink or be lifted with less axial force than impact driving.

A typical unit consists of a frame or clamp that grips the pile, a power unit (hydraulic or electric), and one or more counter-rotating eccentric weights that generate horizontal or near-vertical vibrations. Frequency and amplitude are adjustable to match pile type, size, and soil conditions. Vibrohammers are commonly mounted on cranes or specialized carriers for positioning and handling.

Applications include installation of steel sheet piles, H-piles, tubular piles, and some concrete piles in soft to medium-dense soils, coastal piling, quay construction, and temporary works. They are also used for pile extraction by reversing the vibration and applying upward pull.

Advantages include faster cycle times, lower airborne noise and impulse forces compared with impact hammers, and the ability to extract piles. Limitations arise in dense, coarser-grained, or obdurate strata where vibration alone cannot reach required depths, sometimes necessitating pre-drilling or subsequent impact driving. Environmental and safety considerations focus on ground-borne vibration, potential settlement of adjacent structures, noise control, proper rigging, and compliance with local vibration limits and monitoring requirements.