Patent ID: 11946274
Assignee: DAWSONGROUP PLC
Field: Civil engineering (Other fields)
Classification: CPC E | IPC E

Claim 3:
4. A structure according to claim 1 wherein the structure is further provided with a pressure activated switch which is reacts to the air pressure in the at least one tubular rib, and a source of pressurised air, the pressure activated switch being configured to operate to initiate supply of pressurised air from the source of pressurised air to the interior of the at least one tubular rib if the pressure in the interior of the at least one tubular rib falls below a pre-determined lower threshold, and to cease the supply of pressurised air from the source of pressurised air to the interior of the at least one tubular rib when the pressure in the interior of the at least one tubular rib reaches a pre-determined upper threshold.