Brighton Sealife Centre
Brighton Sealife Centre – Noise & Vibration Prediction & Monitoring
The Overall Nature Of The Project
When the world-famous Brighton Sea Life Centre site was to be re-developed, Acoustic Associates (as we were then) were called-upon to provide extensive consultancy services.
The Sea Life Centre itself site between two roads, one at a level above the Centre and, closer to the beach, one at a lower level. Atop the Sea Life Centre building sat a range of other businesses including food establishments and the old Concorde Music Club.
The scheme involved the demolition of these existing superimposed properties and their replacement with a new range of buildings. Some of these were going to require enhanced structural support and this was to be achieved using piles driven through the Sea Life Centre building itself during a brief Centre closure, lasting only days.
Once the required structural works had taken place, new facilities were to be built atop the Centre as well as a new nightclub alongside the Centre.
The Scope of Services Provided by Acoustic Associates
During the project, which extended over some 15 months, we were instrumental in a number of consultancy areas:
Conduction pre-project environmental noise surveys close to surrounding and nearby noise-sensitive premises to provide a baseline level, against which project noise levels would be compared
Participation in pre-project trials of demolition and construction tooling and plant in order to be able to assess site-specific noise and vibration propagation into the Sea Life Centre building itself and, in particular, to the public areas and the shark tanks.
Assessing, in company with a renowned marine researcher and aquarist, the response behaviour of sharks to vibration signals being received within their shark tanks. This was a critical area because one of the ways in which sharks normally track down their food is by using sensitive tissue to either side of their heads to detect vibration signals. Such signals in the open sea are highly directional and the shark is able to ‘swim up the vibration signal’ to detect their prey.
In the shark tank, however, structural vibration would be coming at them from all sides of the tank and would thus create disturbance and confusion. Above certain levels, which we had to determine, the vibration from construction activity became excessively frustrating for the sharks and they would begin to rub the sides of their heads against the tank wall (maybe a bit like ‘scratching an itch’ for a human?) and thereby destroy the sensitive tissue. We were informed that this sensitive tissue would not then re-grow.
Once the critical levels of vibration had been established, we had to monitor vibration levels continuously over the project period to ensure that the project-induced vibration never reached those critical levels.
We monitored both noise and vibration levels at a number of positions within the Sea Life Centre building to protect both members of the public as well as the marine exhibits
When extra-long piles were to be driven right through the middle of the Sea Life Centre building, we had to first predict the levels of vibration that might occur and to compare these levels with the potentially damaging levels which could have an effect upon the Centre structure.
During the piling operation itself, we were the sole occupants of the Centre building, monitoring the vibration levels directly in real time and in radio contact with the piling team, ready to call a pause or a halt to activity if it became critical. It approached but never exceeded our predicted levels and stayed short of the critical level that might have given rise to building damage (thankfully!).
Once the piling had ceased, we continued to monitor both noise and vibration levels due to construction activity. Monitoring station were distributed about a number of positions within the Sea Life Centre building and at nearby noise-sensitive properties.
Specific Challenges and how these were Overcome
The greatest challenge for this project was looking after the welfare of both the general public and the marine exhibits in the Sea Life Centre building.
In particular and of greatest concern to the Sea Life Centre Aquarists was the health effect upon the sharks of the construction vibration. If critical levels of vibration were exceeded, it could result in the sharks actually destroying the sensitive tissue on the sides of their noses, with the prospect that it would never re-grow and could result in them possibly having to be humanely destroyed.
A significant amount of trialling took place where the vibration levels were monitored simultaneously with the sharks’ behaviour being observed. As levels increased, they would begin to ‘hunt’ back and forth along the side of the tank, much as a tiger will ‘hunt; to and fro within its cage in a zoo as feeding time approaches or if it is disturbed.
On the basis of these exercises, we were able to set do-not-exceed levels of vibration which then became standard criteria for the project as a whole.
The project was highly successful and we were proud to have played a significant part in protecting the sharks.