ELASTIC SUSPENSION OF A MULTI-SPORTS ROOM OVER A LIBRARY. UNIVERSITY OF DEUSTO, CAMPUS OF DONOSTIA-SAN SEBASTIAN

INTRODUCTION TO THE PROJECT

With the aim of improving the university campus, University of Deusto decides for its headquarters in San Sebastian, to add a new Library and a multi-sport room.

As there is not enough space, it is decided to place one on top of the other, leaving the multisport room on the upper floor and the library on the lower one.

The library contains study rooms prepared for work groups. Students require a quiet and peaceful environment in order to carry out such activities.

The multisport hall consists of a basketball / handball / indoor football court, as well as its stands for the public.

Therefore, the conditioning and acoustic insulation had to be optimal to carry out the two activities correctly.

For this project, the acoustic engineering company AAC was selected, a company placed in Vitoria. To achieve the high acoustic performance, research was carried out and AMC MECANOCAUCHO, as well as other suppliers, was contacted to improve the structural noise transmission.

Once the project specifications were known, the AMC MECANOCAUCHO team carried out the necessary calculations and simulations. Important characteristics such as the necessary elastic, mechanical and long life properties were taken in to consideration to fulfil the high level of expectation for this project.

The challenge was even bigger as the mount should enable the maximum possible volume to the room. With this aim, AMC MECANOCAUCHO had to develop a new floor mount that could be embedded into the concrete slab. Based on the standard floating floor mounts, such as FZH+Sylomer®, the mount´s dimensions were modified and a new PU micro cellular compound was added to this mount, a more resilient compound from Getzner Werkstoffe GmbH.

“The challenge was even bigger as the mount should enable the maximum possible volume to the room. With this aim, AMC MECANOCAUCHO had to develop a new floor mount that could be embedded into the concrete slab.”

ACOUSTIC MOUNTS FZH + Sylomer®

The acoustic insulation of a floor using acoustic mounts FZH + Sylomer® is an antivibration system using specific supports embedded directly in to the concrete. These floating floor Jack up mounts are placed on the lower floor and once in position the corresponding room´s concrete is poured over the top. Once the concrete slab has set, the mounts are leveled by the bolts available in the floating floor Jack up mounts. This process raises the new slab and elastically decouples it from the rest of the building by creating an air gap between the lower floor and the concrete slab. This gap provides a high level of thermal and acoustic insulation to the structure, ensuring it is not passed through to the rooms below.

Regarding the long life behaviour, this new anti vibration material is based on a similar blend as the one used in tests carried out at the universities of Berlin and Munich, which showed that the elastic properties of the material remain unchanged after 40 years of service in the field. This means an elastic suspension with optimal properties for the entire useful life of systems insulated with this material.

In addition, PU and Sylodyn® materials offer very high chemical resistance, so their characteristics do not vary in the presence of the main chemical agents that affect the performance and durability of other materials used for soundproofing structures.

PROJECT

For the surface of the activity room, the system between the lower study room and the court floor is made up of a layer of compression concrete on a hollow core slab on which the FZH + Sylomer® acoustic mounts were placed. A concrete slab, a layer of EPS insulation as thermal insulator and another layer of concrete as a levelling element were placed on these acoustic mounts before placing the PVC floor layer.

To avoid the adverse effect that could be produced due to the compressed air between the concrete slab and the building floor, some openings were made in the rock wool of the sides to ensure the correct air movement. This air circulation avoids a spring behaviour from the stagnant air, which as a result increases the natural frequency of the system when it is compressed.

Furthermore, a laser system was used to ensure correct levelling of the slab and a uniform distribution of the load over the entire surface during the lifting of the slab. In this way, excessive deflection of the sides is avoided, which could compromise the stability of the system.

The first result that the AMC MECANOCAUCHO team obtained for this project was that obtained from the simulations carried out with the project data.

For the bleacher area, it was proposed to use a solution using Sylomer® strips under the structure. Considering the total load of the structure and the number of strips to be used, calculations were made and the most suitable soundproofing material was selected from AMC’s range of acoustic materials.

Since any rigid connection between the room and the structure is a way for the transmission of vibration and noise, in addition to the lower insulation of the floating slab, achieving a complete separation of the room from the rest of the structure is critical in this type of construction. For this reason, an elastic sheet was placed around the entire perimeter of the slab to ensure a cushioned joint between the slab and the wall.

Before carrying out the work, Audiotec, a benchmark company in the field of architectural acoustics and a regular user of the floating floor Jack up mounts of the FZH + Sylomer® range, carried out a theoretical calculation of the sound emission foreseen in the study room. These calculations were based on normal noise emission values ​​in the stands of sports halls with similar characteristics, obtaining good results, but always in the absence of confirmation by means of on-site measurement.

After the execution of the floor using the acoustic mounts FZH + Sylomer®, Audiotec carried out an on-site acoustic test in order to know the provisional soundproofing results of the system. The results obtained gave confidence that when the installation was finally complete the level of isolation would be excellent.

For the installation, AMC wall ties type EP400 were used for the wall surface and type EP500 wall ties for the connecting areas between the wall and the ceiling or the concrete slab and the wall.

This last part is important to avoid the rigid connection between the upper floor and the wall, which would reduce the level of soundproofing in the room due to the structural noise that would be transmitted to it. The wall ties used in this project are made of a rubber base, although they would also be available in a Sylomer® version.

For the placement of the wall ties used in this project, a staggered distribution has been chosen, since an excess of wall ties would excessively increase the rigidity of the structure, reducing the level of soundproofing.

With this, the recommended wall ties distribution for this project is the one shown in the following image.

The following drawing shows the final construction scheme of the system.

In the following drawing you can see in greater detail the meeting between the wall and the ceiling of the sports activities room.

While in the following drawing you can see in greater detail the encounter between the wall and the floor of the same.

Prior to any measurement, theoretical calculations were carried out to estimate the equivalente noise level LAeq and the maximum level LAFmax during a basketball game. To do this calculation, the noise source measured during a basketball game in another sports hall with similar characteristics was used.

These theoretical calculation results predict that the noise immission level in the library will be below the recommended maximum value of 40dB:

Once the installation was complete, different measurements were made to study both the airborne and impact noise levels.

Acoustic measurements and comparison with established limits

The measurements with the highest level of importance would be those made between the sports hall and the interior of the library. The airborne noise results for this case are shown in the following graph:

While the results for the isolation against impact noise are shown in the following graph:

Considering that the minimum requirements for acoustic insulation established in Decree 213/2012, of October 16, on acoustic pollution of the Autonomous Community of the Basque Country for activities that are capable of transmitting noise to neighboring premises for residential, administrative, health or educational purposes. The maximum impact noise levels would be 40dB, as shown in the following table, so it can be seen that the sound insulation results offered by FZH + Sylomer® acoustic supports are excellent.

The following table shows the impact noise limits, it can be seen that the sound insulation results offered by FZH + Sylomer® acoustic supports are above and beyond the requirements of the norm.

In the same way, the minimum airborne noise isolations for this type of room would be the following, with the sports hall of this project entering the first group:

The following video shows how the installation of the floating floor Jack up mounts has been carried out for this project. As it can be seen and has been said within this text, the installation process is very simple and does not require either a great infrastructure or any excessive machinery.

This project is a clear example of how to combine two opposing activities in a tight space, such as a sports court and a library, where the impacts of the game and the fans of the first could interfere with the concentration and silence of the latter. These constructive solutions may be the future of building, as cities increasingly have less buildable area but the need to provide spaces for different types of activities within the same construction. Therefore, it is necessary to have the best quality and best acoustic supports, in which AMC MECANOCAUCHO continues to be a benchmark.

To this end, AMC MECANOCAUCHO has a wide range of models of FZH + Sylomer® floating floor Jack up mounts with different load capacities, which can be adapted to a wide range of applications. This is achieved thanks to the possibility of using different densities of Sylomer®, obtaining a load range from 140 Kg to 965 Kg per mount.

AMC MECANOCAUCHO manufactures anti vibration mounts and has a team of application engineers to help your installation needs so do not hesitate to contact our technical department if you require help on this topic.