23A - PROJ - WATER MAIN IMPROVEMENTS

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CITY OF SANTA ANA SPECIFICATIONS PROJECT NO. 11 -6416 SEVENTEENTH STREET WATER MAIN IMPROVEMENTS cause following written approval of the City of Santa Ana. This clause applies to both DBE and non -DBE subcontractors. 1.15 TEMPORARY RECESSED STEEL PLATE BRIDGING When backfilling operation of an excavation in the travel way, whether transverse or longitudinal cannot be properly completed within a work day, recessed steel plate bridging with a non -skid surface and shoring may be required to preserve unobstructed traffic flow. In such cases, the following shall apply: 1. Steel plate installation shall be recessed by milling existing pavement to set flush with finish grade. 2. Steel plate shall fit snug and installed to operate with minimum noise. Bridging shall be secured against displacement. 3. Steel plate used for bridging must extend a minimum of twelve (12 ") inches beyond the edge of the trench. 4. The pavement shall be cold planned a depth equal to the thickness of the plate and to a width and length equal to the dimensions of the plate. Multiple steel plates shall be butted and tack welded as needed to secure plates 6" minimum. The trench shall be adequate to support the bridging and the traffic load. Contractor shall be responsible for determining whether shoring is necessary. The Contractor shall be responsible for the appropriate selection and maintenance of the steel plates, and shoring. Unless specified, recessed steel plate bridging at any given location shall not exceed four (4) consecutive working days in any given week. Backfilling of excavation shall be covered with a minimum of three (3 ") inches of temporary layer of cold asphalt concrete. The following table shows the required minimal thickness of steel plate bridging for a given trench width: Trench Width Minimum Plate Thickness 1.0 foot % inch 1.5 foot % inch 2.0 feet 7/8 inch 3.0 feet 1 inch 4.0 feet 1% inch T -lg r