Workmanship

(a) Forms shall be used, wherever necessary, to confine the concrete and shape it to the required dimensions. Forms shall have sufficient strength to withstand .the pressure resulting from placement and vibration of the concrete and shall have sufficient rigidity to maintain specified tolerances. The main objective is to retain the concrete as the finished facade material. The Contractor therefore shall realize a special and perfect formWork. The drawings showing details and locations of these special formwork shall be submitted by the contractor. The Engineer shall refuse any formWork and any part of the buildings, which has been constructed with a non¬-approved formWork. The Engineer shall refuse any concreting which will not be perfect or may not conform to the approved model.
(b) Earth cuts shall not be used as forms for verticals reinforced concrete Work unless required as such or permitted by the Engineer.
(c) Mud centering shall not be permitted without the prior approval of the Engineer.
(d) FormWork shall be of wrought timber, steel, plywood, proprietary building boards and such special materials, as may be shown on the drawings or approved by the Engineer, which give the required finish to the surface of concrete. Wooden formWork shall be free from loose knots and shall be well seasoned.
(e) The formWork shall conform to the shape, lines and dimensions as shown on the drawings, and be so constructed as to remain sufficiently rigid during the placing and compacting of the concrete, and shall be sufficiently tight to prevent loss of liquid from the concrete. The design and Engineering of the formWork, as well as its construction, shall be the responsibility of the Contractor. Where necessary, to maintain the specified tolerances, the formWork shall be cambered to compensate for anticipated deflections in the formWork due to the weight and pressure of the fresh concrete and due to construction loads The Contractor shall establish and maintain in an undisturbed condition and until final completion and acceptance of the project, sufficient control points and bench marks to be used as references for checking upon tolerances.
(f) Requirements for “facing materials” are given in the Section relevant to ‘Finishing of Formed Surfaces’. The maximum deflection of facing material reflected in concrete surfaces exposed to view shall be 1/240 of the span between structural members.
(g) Where natural plywood forms finish grout cleaned-finish, smooth-¬rubbed-finish, scrubbed- finish or sand-floated-finish is required. Forms shall be smooth (faced with. plywood, liner sheets, or pre¬fabricated panels) and true to line, in order that the surfaces produced will require little dressing to arrive at true surfaces. Where any as-cast finish is required, no dressing shall be permitted in the finishing operation.
(h) Where as cast surfaces, including natural plywood-form-finish are specified, the panels of material against which concrete is cast shall be orderly in arrangement, with joints between panels planned in approved relation to openings, building corner and other architectural features.
(i) Where panels for as-cast surfaces are separated by recessed or otherwise emphasized joints, the structural design of the forms shall provide for locating form ties, where possible, within the joints so that patches of tie holes will not fall within the panel areas.
(j) Forms shall not be re-used if there is any evidence of surface wear and tear or defect which would impair the quality of the surface finish. Forms shall be thoroughly cleaned and properly coated before re-use.
(k) The formWork shall be designed so that the soffits of slabs and sides of beams, columns, and walls may be removed first, leaving the forms to the soffits of beams and their supports in position.
(l) Forms shall be sufficiently tight to prevent loss of mortar from the concrete. Unless otherwise specified in the Contract Documents chamfer strips shall be placed in the corners of forms to produce beveled edges on permanently exposed surfaces. Interior corners on such surfaces and the edges of formed joints will not require beveling unless required by the Contract Documents.
(m) Positive means such as wedges or jacks for accurate adjustment and for proper removal of shores and struts shall be provided and all settlement shall be monitored during concrete placing operation. Forms shall be securely braced against lateral deflections.
(n) Where concreting of thin members is required to be carried out within formWork of considerable depth, temporary openings in the sides of the formWork shall be provided where necessary to facilitate the placing and consolidation of concrete. Small temporary openings shall also be provided at the bottom of the formWork for columns, walls and deep beams to permit the cleaning out of debris and observation immediately before concrete is depoSited.
(o) Form ties shall be constructed so that the ends or end fasteners can be removed without causing appreciable damages at the faces of the concrete. After the ends or end fasteners of form ties have been removed, the embedded portion of the ties shall terminate not less than 2 times diameter or twice the minimum dimension of the tie from the formed faces of concrete to be permanently exposed to view and in no case shall this distance be less than ¾ inch. (20 mm). When the formed face of the concrete is not to be permanently exposed to view, form ties may be cut off flush with the formed surfaces. Through bolts may be permitted provided that they are greased to allow for easy withdrawal and the holes. Subsequently made good. Through bolts are not to be used on water retaining structures.