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PART 3 — EXECUTION <br />3.1 ERECTION <br />A. General. <br />1. Erect forms substantial and sufficiently tight to prevent leakage of paste, and braced or <br />tied to maintain the desired position, shape and alignment before, during, and after <br />concrete placement. <br />2. Use adequate walers, stiffeners, and braces to insure proper alignment. <br />3. Provide temporary openings at the bottom of column and wall forms, and at other <br />locations where necessary to facilitate cleaning and inspection. <br />4. Temporary openings in wall, or column forms used to limit the free fall of concrete to a <br />maximum of four feet (4') shall be located to facilitate placing and compaction of the <br />concrete. Such openings in walls shall not exceed ten feet (10') laterally to avoid <br />moving concrete laterally more than five feet (5'). <br />5. If tremies of proper lengths are used for depositing concrete in walls or columns, <br />temporary openings for concrete placement will not be required. <br />6. Whenever the top of a wall will be exposed to weathering, do not extend the forms on <br />one side above the top of the wall; bring to true line and grade. <br />7. At other locations, bring forms to a true line and grade, or provide a wooden guide strip <br />at the proper location on the forms so that the top surface can be finished with a screed <br />or template for concrete which is to have a specified elevation, slope, or contour. <br />8. At horizontal construction joints in walls, do not extend the forms on one side more <br />than two feet (2') above the joint. <br />9. Flat, segmental forms not more than twenty-four inches (24") wide may be used for <br />forming curved surfaces twenty-five feet (25') in diameter or larger. <br />10. Where concrete is placed against rock, remove all loose pieces of rock and clean the <br />exposed surface with a high pressure hose. <br />11. Where concrete is placed against gravel or crushed rock which does not contain at least <br />twenty-five percent (25%) material passing a No. 4 sieve, cover such surfaces with <br />polyethylene film to protect the concrete from loss of water. Lap joints in the film at <br />least four inches (4"). <br />12. Where concrete is placed against void form, void form is to be covered with plywood <br />and the joints taped. Plastic sheeting is to be used at the edges and the excavation <br />sloped away from the foundation area. <br />13. Do not reuse forms with damaged surfaces. <br />14. Locate form ties and joints in an uninterrupted pattern for smooth and uniform surface. <br />15. Align all form ties, horizontally and vertically, on any one structure. <br />Concrete Formwork February 2017 03100-4 <br />