Agmt13 Pacific Electric Contracting, Inc.

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C. Forms shall be carefully set to the alignment and grade established and shall conform to the required dimensions. Forms shall be rigidly held in place by stakes set at satisfactory intervals. Sufficient clamps, spreaders and braces shall be installed to insure the rigidity of the forms. D. Forms for back and face of curbs, lip of gutters and edge of walks, valley gutters or other surface slabs shall be equal to the full depth of the concrete as shown, noted or called for on the plans or detail drawings. Composite forms made up from benders or thin planks of sufficient ply to ensure rigidity of the form in the shape required may be used on curves and curb returns. 3.04 PLACING STEEL REINFORCEMENT A. Bars shall be free of mortar, oil, dirt, excessive mill scale and scabby rust and other coatings of any character that would destroy or reduce the bond. All bending shall be done cold, to the shapes shown on the plans. The length of lapped splices shall be as follows: 1. Reinforcing bars No. 8, or smaller, shall be lapped at least 45 bar diameters of the smaller bar joined, and reinforced bars Nos. 9, 10, and 11 shall be lapped at least 60 bar diameters of the smaller bars joined, except when otherwise shown on the plans. 2. Splice locations shall be made as indicated on the plans. B. Reinforcement shall be accurately placed as shown on the plans and shall be firmly and securely held in position by wiring at intersections and splices and by using precast mortar blocks or ferrous metal chairs, spacers, metal hangers, supporting wires, and other approved devices of sufficient strength to resist crushing under applied loads. Supports and ties shall be such as to permit walking on reinforcing without undue displacement. C. Reinforcing shall be placed so as to have the following minimum concrete cover: Surfaces exposed to water 4" Surfaces poured against earth 3" Formed surfaces exposed to earth or weather 2" Slabs, walls, not exposed to weather or earth 1" D. Minimum spacing, center of parallel bars shall be two and one half (2-1/2) times the diameter of the larger sized bar. All reinforcing shall be securely tied in place prior to pouring concrete. Placing of dowels or other reinforcing in the wet concrete is not permitted. 3.05 MIXING CONCRETE A. All concrete shall be transit mixed in accordance with the requirements of ASTM Designation C94. Transit mixed concrete shall be mixed for not less than ten (10) minutes total, of which not less than three (3) minutes shall be on the site just prior to pouring. Mixing shall be continuous with no interruptions from the time the truck is filled until the time it is emptied. Concrete shall be placed within one hour of the time water is first added. B. Hand mixing of concrete for use in concrete structures will not be permitted. 3.06 PLACING CONCRETE A. Subgrade sha�l be thoroughly wetted prior to the placing of concrete for all concrete placed directly on soil. All standing water shall be removed prior to placing of concrete. B. No concrete shall be placed until the subgrade and the forms have been approved. C. Concrete shall be conveyed from mixer to final location as rapidly as possible by methods preventing separation of the ingredients. Deposit concrete as nearly as possible in final position to avoid re-handling. D. Concrete shall be placed and compacted in forms without segregation by means of inechanical vibration or by other means as approved by the Engineer. Vibration shall continue until the CONCRETE IMPROVEMENTS 02550-6 EAST BAYSHRORE ROAD STREET LIGHTING PROJECT