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<br />I <br />'"-.-, <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />o <br /> <br />Technical Advisory <br /> <br />us. DeporImenl <br />~ llonsportation <br />federal ~ <br />AdmInIstration <br /> <br />Subject <br /> <br />SCOUR AT BRIDGES <br /> <br />Classification Code <br />T 5140.20 <br /> <br />Date <br />September 16, 1988 <br /> <br />Par. 1 <br />2 <br />3 <br />4 <br /> <br />Purpose <br />Background <br />Recommendations for Developing and Implementing a <br />Scour Evaluation Program <br />Existing Policy and Guidance <br /> <br />1. PURPOSE. To provide guidance on developing and implementing <br />a scour evaluation program for: <br /> <br />a. designing new bridges to resist damage reSUlting from <br />scour; <br /> <br />b. evaluating existing bridges for vulnerability to scour; <br /> <br />c. using scour countermeasures; and <br /> <br />d. improving the state-of-practice of estimating scour at <br />bridges. <br /> <br />2. BACKGROUND <br /> <br />a. The need to m1n1m1Ze future flood damage to the nation's <br />bridges requires that additional attention be devoted to <br />developing and implementing improved procedures for <br />designing, protecting and inspecting bridges for scour. <br />(See National Bridge Inspection Standards, 23 CFR 650 <br />Subpart c.) Current information on this subject has been <br />assembled in the Attachment to this Technical Advisory <br />entitled, "Interim Procedures for Evaluating Scour at <br />Bridges." The interim procedures are furnished for use <br />at this time and will be incorporated at a later date in <br />a Federal Highway Administration (FHWA) design"manual <br />entitled, "Hydraulic Engineering Circular No. 18, Scour <br />at Bridges," which is scheduled for publication in 1989. <br /> <br />Level 3: <br /> <br />Headquarters (NR,RT,HI,DF,HO,HS) <br />Regions (ST) <br />Divisions (BR) <br />All Direct Federal Divisions <br />SHA's(Through Divisions) <br /> <br />OPt: HNG -31 <br /> <br />DISTRIBUTION: Leve I 2: <br />