Harcombe Cross is located on the A38 between Exeter and Plymouth over the B3344, just north of Chudleigh. The A38 Harcombe Cross Bridge is a single span concrete slab deck carrying the A38 dual carriageway above, with a single carriageway underneath. There were paved revetments each side of the carriageway leading to the abutments.
Due to the age of the bridge, the existing 250 tonne capacity bearings had deteriorated and needed to be replaced. Freyssinet were appointed by Enterprise Mouchel to undertake the work in 2013. Freyssinet started work on site in September 2013. The works undertaken included:
• Design, supply and install 2 new guided pot bearings to replace the existing spherical guided bearings • Design, supply and install 10 new free pot bearings to replace the existing spherical free bearings • Removal of the existing bearings and creation of jacking pockets into the abutment shelf by hydrodemolition • Design, supply and installation of a jacking system to enable the removal and replacement of the above bearings.
Freyssinet used special low height pot jacks in a bank of 3no between each bearing. This helped to reduce the pressure of the bearing on the existing concrete, whilst the deck was jacked. The deck was jacked approximately 2mm and the bearings were undermined using hydrodemoliton, by our sister company, Aquaforce. The bearings were then removed. Once the bearings had been removed, second stage concrete repairs were carried out to the deck soffit in the difficult to access areas. Once the new bearing grout and concrete repairs had achieved the required strength, the deck was lowered.
The works were all carried out to the clients satisfaction. They were completed on programme, on budget with no disruption to the A38 above.
