Civil engineering work to raise the level of Route Goward

Civil engineering work to raise the level of Route Goward will take place during Long Shutdown 1. The work will begin on 18 March 2013 and is expected to last around 5 months.

Route Goward runs over the top of the PS tunnel and is the only access route to the inside of the ring. The layer of shielding backfill beneath this road is the thinnest anywhere on the PS ring. As the purpose of this shielding is to protect against the ionising radiation emitted by the accelerator when in operation, this road has been classified as a “supervised radiation area” according to radiation protection regulations. This classification was merely a temporary solution and, on the recommendation of the PS Radiation Working Group (PSRWG), the decision has been taken to raise the surface level permanently by around 2 m in order to increase the thickness of the shielding and thus lower the dose rate to that of a non-designated area.

As the PS tunnel itself is unable to withstand the weight of the additional depth of backfill, a bridge of reinforced concrete will be built to bear the extra load. Raising the ground level above the PS tunnel will also require a stretch of road of approximately 100 m to be raised and supporting walls to be constructed along the side of the road. However, the layout of the future road will be the same as it is now, with two lanes of traffic, each 2.9 m wide. At around 9.5% in gradient, it will be steeper than the current gradient of 6.3%.

The first phase of work, lasting around three weeks, will consist of constructing a 3 m-wide non-asphalted temporary access route with a 10% gradient (see map). This phase of work will not affect users, except that only one lane of the road will be open while the work is in progress. 

Route Goward will be completely closed from mid-April while the work takes place. The temporary access route will then be available to CERN users, but for safety reasons, use of this road will only be authorised for the transportation of equipment and deliveries and for emergency services. Pedestrians will be required to use the alternative routes provided (see map) and will have to park their vehicles outside the PS ring. In addition, the temporary access route will also be closed for an estimated period of around two weeks and will be open for use only during certain specified time slots, which will be communicated to users.

We thank you in advance for your patience and co-operation while the work is under way.

GS-SE Group