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I <br /> I1 2. Have a compressive strength equal to or greater than that of the concrete in which <br /> 2 they are embedded. <br /> 3 <br /> 4 In slabs, each precast concrete support shall have either: (1) a grooved top that will hold <br /> 5 the reinforcing bar in place, or (2) an embedded wire that protrudes and is tied to the <br /> 6 reinforcing steel. If this wire is used around epoxy-coated bars, it shall be coated with <br /> I7 plastic. <br /> 8 <br /> 9 Precast concrete supports may be accepted based on a Manufacturer's Certificate of <br /> I10 Compliance. <br /> 11 <br /> 12 In lieu of precast concrete supports, the Contractor may use metal or all-plastic supports to <br /> I <br /> 13 hold uncoated bars. Any surface of a metal support that will not be covered by at least 1/2 <br /> 14 inch of concrete shall be one of the following: <br /> 15 <br /> 16 1. Hot-dip galvanized after fabrication in keeping with AASHTO M232 Class D; <br /> II 17 <br /> 18 2. Coated with plastic firmly bonded to the metal. This plastic shall be at least 332 <br /> I19 inch thick where it touches the form and shall not react chemically with the <br /> 20 concrete when tested in the State Materials Laboratory. The plastic shall not <br /> 21 shatter or crack at or above -5°F and shall not deform enough to expose the metal <br /> 22 at or below 200°F; or <br /> 23 <br /> 24 3. Stainless steel that meet the requirements of ASTM A493, Type 302. Stainless <br /> 25 steel chair supports are not required to be galvanized or plastic coated. <br /> 26 <br /> 27 In lieu of precast concrete supports, epoxy-coated reinforcing bars may be supported by <br /> 28 one of the following: <br /> I29 <br /> 30 1. Metal supports coated entirely with a dielectric material such as epoxy or plastic, <br /> 31 <br /> 32 2. Other epoxy-coated reinforcing bars, or <br /> II 33 <br /> 34 3. All-plastic supports. <br /> 35 <br /> 36 Damaged coatings on metal bar supports shall be repaired prior to placing concrete. <br /> 37 <br /> ' 38 All-plastic supports shall be lightweight, non-porous, and chemically inert in concrete. All- <br /> 39 plastic supports shall have rounded seatings, shall not deform under load during normal <br /> 40 temperatures, and shall not shatter or crack under impact loading in cold weather. All- <br /> 41 plastic supports shall be placed at spacings greater than 1 foot along the bar and shall <br /> I42 have at least 25 percent of their gross place area perforated to compensate for the <br /> 43 difference in the coefficient of thermal expansion between plastic and concrete. The shape <br /> 44 and configuration of all-plastic supports shall permit complete concrete consolidation in and <br /> I <br /> 45 around the support. <br /> 46 <br /> 47 A "mat" is two adjacent and perpendicular layers of reinforcing steel. In bridge decks, top <br /> I 48 <br /> and bottom mats shall be supported adequately enough to hold both in their proper <br /> 49 positions. If bar supports directly support, or are directly supported on No. 4 bars, they shall <br /> 50 be spaced at not more than 3-foot intervals (or not more than 4-foot intervals for bars No. 5 <br /> City of Everett Page AM-37 Amendments <br /> Everett Downtown Streetscape Improvement March 22, 2019 <br />