Environmental Statement volume 4 - Chiltern Evergreen3

Figure 52.6 AP5 – OXD40 UnderbridgeThe water crossing at this location is in need of upgrading as it has been replaced sincethe line was converted to single track use, and consequently is under-specified for adouble track, high speed railway. The underbridge allows the railway to cross a MainRiver, as shown in Figure 6 (orange marker and arrow), and lies in Flood Zone 3 asdefined by the EA Flood Map.The existing superstructure is to be demolished and replaced with two longitudinallyspanningsteel/concrete composite ‘U’ type half-through decks. The decks will besupported on the existing substructure via articulated bearings and new precastreinforced concrete cill beams.The existing abutments, wingwalls and foundations are to be retained, adapted andreused to support the proposed U-decks and walkways. It is therefore proposed that theworks can be classed as re-decking only.The crossing is a Main River crossing and hence the work will require a Flood DefenceConsent under the terms of the proposed Protective Provisions in the TWA Order. Theconditions of the consent will be included within the Construction Method Statement.This is discussed further within Section 3.6.10