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2023 Docket Enabling Ordinance December 19, 2023 <br />Page 108 <br /> <br /> <br />7. WSDOT Bridge Detailing Manual <br />8. Washington Department of Fish and Wildlife Water Crossing Design Guidelines <br />9. U.S. Army Corps of Engineers <br />10. All applicable RCW and WAC requirements. <br />B. A hydraulic analysis shall be performed for all culverts, open channels and box culverts in <br />accordance with the WSDOT Hydraulics Manual and KCC 12.04 Article V. Such drainage <br />structures shall be sized at a minimum and located as per the analysis; provided, <br />however, that no cross roadway culvert shall be less than eighteen inches in diameter. <br />C. All bridges shall be constructed of reinforced concrete unless otherwise approved by the <br />Public Works Director. Spans may be pre-tensioned or post-tensioned concrete girders <br />or beams with a concrete deck. Steel or other metal bridges may be used only with the <br />approval of the County Engineer. Treated timber bridges may be considered for private <br />roads only. <br />D. Bridge and major drainage structure clear width shall match the full width of the traveled <br />lanes and shoulders of approach roads including bikeways, trails, and pedestrian <br />facilities. The clear width of the structure shall accommodate the existing approach road <br />section, or the future roadway section as defined in any applicable adopted master plans <br />or capital improvement plan, whichever is greater. The minimum required clear width for <br />all bridges and major drainage structures shall be the minimum access requirements for <br />emergency vehicles. See Section 12.04.04.110. <br />E. Subject to approval by the County Engineer, bikeways, trails, and pedestrian facilities <br />may be omitted from the width of the structure only if a parallel structure is provided to <br />accommodate these uses. <br />F. Overhead vertical clearances for all bridges and major drainage structures shall be no <br />less than 16.5 feet. <br />G. All new bridges and major drainage structures shall meet a minimum design load <br />structural capacity of HL-93, or as required by KCC 20.02.050. The load rating for <br />privately owned bridges shall be posted as required by KCC 20.02.050.