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<br />o Has an engineering scour evaluation study been made? If so, is the <br />bridge scour critical? <br /> <br />o If the bridge is scour critical, has a plan of action been made for <br />monitoring the bridge and installing scour countermeasures? <br /> <br />o What do comparisons of stream bed cross-sections taken during successive <br />inspections reveal about the stream bed? Is it stable? Degrading? <br />Aggrading? Moving laterally? Are there scoUr holes around piers and <br />abutments? <br /> <br />o What equipment is needed to obtain stream bed cross-sections? (rods, <br />poles, sounding lines, etc.) - <br /> <br />o Are there sketches and aerial photographs to indicate the plan form <br />location of the stream and whether the main channel is changing <br />direction at the bridge? <br /> <br />o What type of bridge foundation was constructed? (Spread footings, <br />piles, drilled shafts, etc.) Do the foundations appear to be vulnerable <br />to scour? <br /> <br />o Do special conditions exist requiring particular methods and equipment <br />for underwater inspections? (divers, boats, electronic gear for <br />measuring stream bottom, etc.) <br /> <br />o Are there special items that should be looked at? (Examples might <br />include damaged riprap, stream channel at adverse angle of flow, <br />problems with debris, etc.) <br /> <br />C. BRIDGE INSPECTION <br /> <br />During the bridge inspection the condition of the bridge waterway opening, <br />substructure, channel protection, and scour countermeasures should be evaluated <br />along with the condition of the stream. <br /> <br />The proposed revision (see Appendix C) of the FHWA Recording and Coding Guide <br />(5) contains revised material for the following three items: <br /> <br />o Item 60 Substructure; <br /> <br />o Item 61 Channel and Channel Protection; <br /> <br />o Item?l Waterway Adequacy <br /> <br />The guidance in the revised Recording and Coding Guide for rating the present <br />condition of Items 61 and 71 is set forth in detail; guidance for rating the <br />present condition of Item 60, Substructure is general and does not include <br />specific details for scour. The following sections present approaches to <br />evaluating the present condition of the bridge foundation for scour and the <br />overall scour potential at the bridge. <br /> <br />52 <br /> <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I 'I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />