CONSTRUCTION TECHNOLOGY
THE SELECTION AND APPLICATION OF
HYDRAULIC VIBRATORY HAMMERS by Nick Chua, Country Manager (Philippines), Foundation Associates Engineering Pte Ltd The different types of equipment available and their merits are presented. Introduction Hydraulic vibratory hammers are used in a wide variety of applications. Apart from their use in driving and extracting elements such as sheet piles and pipes, vibratory hammers are also used for soil densifying or vertical drainage. With currently available technology, it is possible to use vibratory hammers to drive casings for oil & gas pipelines offshore, to a depth of up to 120 m under water.
Principle behind the functioning of a vibratory hammer A vibratory hammer drives the object into the soil through the centrifugal force generated by its eccentric
Mr Nick Chua
weights, which, in turn, generates vibrations in the adjacent soil particles, that reduce the soil resistance. The dynamic weight of a hydraulic impact hammer produces a high pulsating load at a low frequency. With a hydraulic vibratory hammer, the opposite will occur. A relatively low steady load is produced at a high frequency. With the low impact of the hydraulic vibratory hammer, the risk of fractures and cracks is eliminated. A vibratory hammer is used to drive sheet piles, pipes or other elements into the soil by vertical vibrations. The adjacent soil particles are initiated into motion and thus the soil is ‘loosened’. The dynamic weight of the hammer will drive the steel casings / sheet piles etc into the soil. Extraction is done using a crane.
Main Components of Vibratory Hammer
Suppressor Unit
SUPRESSOR
Supressor Structure
GEAR CASE
Elastomers
Supressor Housing
CAISSON BEAM CLAMP
How does it work? The hydraulic motor will rotate the eccentric weights in the gear case. Vibrator Hammer
The rotation of the eccentric weights creates the vibrations
Hydraulic Powerpack
The main power source to the vibratory hammer hydraulic system comes fron the Hydraulic Powerpack.
Components of a hydraulic vibratory hammer and how it works. 24
THE SINGAPORE ENGINEER November 2021
