The bridge has been assessed by Devon County Council for its ability to carry assessment loading. The bridge essentially comprises two different elements, the original medieval masonry arches and the more recent concrete and steel widened sections which rest on the old masonry piers.
A number of record drawings were available from the widening of 1925 and the additional repair work in 1970 but a significant amount of essential information was missing. Therefore a number of investigations were carried out on the bridge to determine the reinforcement sizes and layout and the concrete strengths in the widened sections. The result of this assessment was contained in an interim report completed in July 2002 and a final assessment report completed in September 2002.
In summary, the masonry arch element of the structure is adequate to carry full assessment loading and only a few minor maintenance repairs are required to the masonry. The concrete widened sections are limited to a 3 tonne assessment loading. The cantilever walkway on New Road is also limited to a 3 tonne assessment loading.
As a result of this assessment a 3 tonne weight limit was imposed on the bridge in July 2002.
 | Core samples were taken from the reinforced concrete widening using a lorry mounted platform to gain access under the bridge. These cores were crushed to determine the concrete strength. Concrete samples were also tested for chloride content which is known to cause reinforcement corrosion. A number of samples had concentrations above the recommended limit which would explain the extensive corrosion problems observed. |
Although the reinforced concrete beams and encased steel beams are not adequate to carry 40 tonnes assessment loading the weakest element is the reinforced concrete slab spanning between the two. This has an assessment strength of 3 tonnes as it is not able to carry individual wheel loads from vehicles. It is known that lorries occasionally mount the pavement and therefore a 3 tonne weight limit was imposed on the bridge. an exemption was granted to local buses on the condition that drivers were made aware of the problem and would not mount the footway. |  |
Road beams running under new road cantilever out from the quay wall to support reinforced concrete beams which carry the walkway.
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