Bennett Associates

Engineering Design Consultants

Dehumidification Project to Halt Corrosion on Forth Road Bridge

 
   

The same team that worked on the Forth Road Bridge cable inspections in 2004 has been appointed to install state of the art dehumidification equipment on the main cables of the bridge. The Forth Estuary Transport Authority (FETA) has approved the appointment of C Spencer Ltd to carry out the work. Bennett Associates will be working alongside C Spencer Ltd on the £7.8m contract.

C Spencer and Bennett Associates were involved in the unwrapping and original internal investigation of the cables of the Forth Road Bridge in 2004. The inspection revealed that the cables had suffered significant corrosion; the current loss of strength, as verified by a Scottish Executive-commissioned independent audit, is believed to be in the region of 8 to 10 percent. The discovery of corrosion in older suspension bridges in the USA prompted FETA to become the first European bridge authority to carry out an internal cable inspection.

A package of measures was put in place by FETA to monitor the corrosion and minimise further deterioration. Dehumidification was quickly identified as the best line of defence against further corrosion.

C Spencer, working in collaboration with Bennett Associates, will install equipment that will inject dry air into the main two cables of the Forth Road Bridge . Dehumidification works on the principle that if the relative humidity of the air within the cable is reduced to 40 percent, then corrosion cannot occur.

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Related links:
.Innovative Solutions for First Forth Bridge Inspection
.Bridging Gaps

 

 
Forth Road Bridge
Forth Road Bridge

Bennett Associates was involved in the initial cable inspection
Bennett Associates was involved in the initial cable inspection