Underwater Demolition

A novel approach to demolition - hand held tools and wet suits allowed the demolition crew to remove old bridge foundations in two weeks
Clearing and uncovering the river running through the Danish city og Aarhus created a problem for one Danish contractor, who faces the challenge of removing underwater foundations. Hand-held tools and wet suits were the solution.
Over the last few years, the Danish city og Aarhus has seen a major transformation with many buildings having been renovated. A major part of the work is the opening up of the river that runs through the city centre.For many years, it had been buried out of sight under concret and asphalt, but this is now changing, as it is to become a major element in the modified Aarhus city centre look.

Attempts to demolish the foundations using machinery - first using an axcavator with a bucket and then excavator-mounted hydraulic breaker - came to nothing (and nearly blew the excavator's hydraulic system when water got into it).

General contractor Phil & Sons was awarded a contract that involved cleaning out the river and making chances to its course.

It was during the clean-out that Phil descovered a problem; underwater foundations that originally supported a road that crossed the river. These had to be removed.
As a result, Phil started to run late on the contract and risked incurring fines because of the delay. In the nick of time, they found a possible solution - hand tools and wet suit. It was identyfied that a 23kg (50.5 lb) Hycon HH23 hydraulic breaker would be able to work underwater as a result of the fact that its hydraulic system is closed, a fact that prevent water penetration.

Pihl then brought specialist demolition company Total Diamenten to actually carry out the work, and rented the Hycon equipment from Hycon's Danish dealer Tzacho, along with a Honda HPP 13 power unit and 30 m (98 ft) og special lightweight hydraulic hose.

The total workers then simply donned their wetsuits, jumbed into the river and began the demolition og the foundations structure by hand. While perhaps not the most pleasant of working conditions, the task took less than two weeks.

Power for the breaker came from a Honda 13 hp unit
d&ri may-june 2008