Resonator installed sheet piles around dam

The challenge

How do you install profiles in high risk area, which are sensitive to vibrations eg urban areas, dyke reinforcements and oil & gas industry?

The resonance technology is used on sites where zero vibrations are a must and where a variable moment vibratory hammer is even not sufficient. The resonance technology is especially suitable for standalone profiles like tubes and H-beams, anchors & micropiles as well as U sheet piles.

The main difference with the Resonator and a conventional vibratory hammer is that the resonance technique will not cause any direct movement in the soil and therefore no vibrations in the surrounding soil are measured.

How can this be possible as resonating is also vibrating? Everything has its own natural frequency; The natural frequency of the soil, depending on the structure, is around 20-30 Hz. The resonance technique uses a high frequency of 80-180 Hz. Due to the high operating frequency of the resonance technique, the soil has no time to move; the soil is too massive to “keep up “with the pile . The result is that there are no vibrations, and therefore no settlement perceptible in the area. High accelerations at low amplitude generate pile penetration with imperceptible ground vibration. The own frequency of a profile is mainly determined by the length of the profile. The shorter the profile the higher the own frequency. ( 5100 / 2 x Length ).

In Canada, a challenging project was undertaken where sheet piles needed to be installed around a dam without causing any harmful ground movement. The hydroelectric John Hart Dam was built in 1947. Reinforcements to the dam are essential due to the risk of earthquakes. Customer FRPD (Fraser River Pile and Dredge) and the team of Dieseko Group and their subsidiary PVE USA opted for the Resonance Technology with Resonator model RD260.

There was no doubt that the risks associated with using a vibratory hammer were too high.

Resonance technology is a totally different sort of technique to get objects in the ground, instead of moving it up and down, the object is brought in its own frequency, making it longer and shorter and in that way penetrating the soil. The decision was made after carefully examining all the available information and several Teams meetings. The advice to use a Resonator was accepted by FRPD. A Dieseko Group engineer operated the Resonator on-site, and the first phase of the project was successfully completed without any issues.

Great example of a very special application to fit the needs of our customers

FRPD’s scope of work included driving two H-Piles on each end of a sheet pile wall. BC HYDRO’s design specified the use of the resonant hammer for the install of those H-Piles and the Sheet Pile Wall. Once the H-Piles were installed, FRPD welded a cross beam to connect the two H-Piles together to create the driving frame. The driving frame was used to keep the sheet pile alignment within tolerance. The sheet pile alignment was crucial due to the fact that pre-fabricated structural whalers were to be installed in between the Sheet Pile Wall and the Concrete Main Dam. The resonant hammer installed 49 type U sheet piles prior to installing the structural whalers. Each sheet pile was driven to a full depth of 10m prior to moving on to the adjacent sheet.