Design and Installation of Sprung Jack-Up Concrete Floating Floor for Pure Gym Bicester

Pure Gym Bicester

We (Mason UK) were brought on board by Pure Gym to provide a Jack Up Sprung Floating Floor totalling around 800 square metres for their new site on the first floor of a steel frame building on the new Bicester Business Park.

Prior to works commencing we attended site with Acoustic consultant RBA to ascertain not only that a floating floor would be required in the working areas of the gym, to prevent disturbances to shops and restaurants below, but to also confirm which floating floor system would be most appropriate.

Due to the lightweight structure and following on from the drop tests undertaken on our test floor with both spring and rubber options, RBA confirmed a 100mm thick concrete floating floor on springs with a natural frequency of 4Hz, and a 100mm air gap would be required.

The shell of the building had already been completed and Mason UK were brought on directly by the developer to install the floating floor prior to Pure Gym fit out contractor completing the remainder of the fit out.

This posed its own problems. Without a principal contractor on site, how would full sheets of reinforcing mesh approximately 5.0m long get to the first floor of a finished building? Luckily the building maintenance team were able to remove a large window, and Mason UK brought on GGR for a contract lift to provide the expertise to lift the bulky materials safely into the first floor.

Once the materials were in place, the preparation work could begin. First the marking out, then the placing of polythene separation membrane, shutters, and Mason FS spring jacks.

To ensure the jacks were located correctly and unable to move they were tied in place with 10mm rebar set on the jack lugs. After the bars were placed two layers of reinforcing mesh were laid to complete the prep work prior to receipt of concrete.

Without the need for a costly timber form, the jack up system is extremely quick to install. 800m2 of floor was completed in only 8 days from arriving on site.

Mason UK subcontracted out the concrete operations to Nationwide Concrete, who provided the concrete pump and labour to complete the whole pour in a single operation. 15 concrete wagons in total supplied the job with 3 to 4 wagons being discharged per hour. The concreting operations were completed by 4pm.

Once the concrete had cured sufficiently to enable the floor to be jacked, Mason returned to site and with a team of guys lifted the floor to provide a 100mm air gap. To achieve this, each casting was opened, and a spring inserted. An inner compression casting was then wound down onto each spring two turns at a time. Each turn compresses the spring by 6mm and when the force of compression in that spring equals that of the concrete assigned to that spring then the floor lifts.

The finished floor jacked to required elevation can be seen below.

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Acoustic Floating Floors

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The jack up spring floating floor is used for low frequency isolation or where impact isolation is required, such as bowling alleys, gymnasia and health clubs.

Acoustic Isolation of Gymnasia

A gym by its very nature is a place where people participate in noisy activities – running, jumping, shouting, ball sports and weight lifting etc are all part of typical gym usage; any construction must withstand this treatment whilst maintaining acoustic separation to prevent noise and structural vibration transmission.