ADVANTAGES OF DOUBLE STEP WALL TIES FOR NOISE ISOLATION
The U Arena is a multipurpose stadium located in Nanterre that was opened on October 2017 and can accommodate up to 40.000 spectators.
Avel Acoustique has carried out the project to acoustically isolate the different parts of the stadium, and a natural frequency below 10Hz at very low loads was required to isolate the walls of the stadium.
In order to minimize the noise transmission, rigid connections between the acoustic walls and the structure of the building must be avoided.
The requirement of having a natural frequency below 10Hz at very low loads requires the use of a wall tie with very low stiffness:
However, low stiffness means high deflections at low loads.
This limitation can be avoided with the use of wall ties with double step behavior. It provides low stiffness at low loads while it avoids excessive displacements at high loads. The charts below show an example of this phenomenon:
The new wall tie EP + Sylomer® LMR has been developed following this concept:
| They are made of parts of two different densities of Sylomer®, which is a microcellular polyurethane material that provides superior noise isolation than rubber or cork materials |  |
| This configuration allows high isolation levels at low loads while it assures the stability when the wall tie is subject to higher dynamic loads. |
Furthermore, as the noise must cross several different materials, each one with its own acoustic impedance, part of the energy is reflected in each material change border, as it is shown in the schematic below:
Higher the impedance difference in each border, higher the energy of the reflected waves and smaller the energy of the transmitted waves.
The elastic properties of this wall tie are shown below:
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Its geometry allows an easy and flexible assembly of the product:
The technical data sheet and the drawing of this wall mount can be downloaded in the links below:
