Many multi-span bridges in the UK are constructed as a series of simply-supported, pretensioned precast concrete beams composite with an in-situ reinforced concrete deck slab. The majority of these bridges incorporate an expansion joint over each pier. Experience has shown that these expansion joints are prone to leak, allowing surface water and de-icing salts to penetrate the bridge deck and sub-structure. The resulting chloride-induced corrosion of the steel reinforcement is then a serious and potentially expensive problem. Most of the intermediate expansion joints can be eliminated from these precast beam and slab bridges by building-in continuity at the supports. Contractor Report 247 entitled: "Investigation of methods of achieving continuity in composite concrete bridge decks" identified five methods in use in the UK and worldwide of building-in continuity. This report contains the results of a survey of twenty bridges, including several of each type, to assess their relative durability and effectiveness in service. It reinforces the conclusion of the earlier report (see IRRD 838966) that building-in continuity is an effective way of enhancing the durability of multi-span bridges.

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