This section is from the book "The Law Of Contracts", by William Herbert Page. Also available from Amazon: Commercial Contracts: A Practical Guide to Deals, Contracts, Agreements and Promises.
Forms. - All forms for moulded concrete work shall be constructed of sufficient strength to obtain the necessary rigidity to prevent any motion of the forms while concrete is being placed, and must be strong enough to carry any load which may come upon the concrete within thirty (30) days from the date of placing the concrete. Before work is commenced the Contractor shall submit detail plans of the method of constructing forms to the Engineer, but the submitting of such plans will not relieve the Contractor of any responsibility should any fault appear during the construction.
Forms shall, in general, be composed of tongue and grooved sheeting if 7/8 - inch sheetings is used, or carefully matched stuff if heavier sheeting is used. Each plank must be of uniform width, fastened to the studding in true horizontal lines, ends and edges being carefully butted together. They must be as nearly as possible water-tight, and must be surfaced on the side next the concrete for all surfaces which will be exposed in the finished work.
Planking once used in forms shall be cleaned before using again. Deformed, broken or defective forms shall be removed from the work. Forms shall be constructed by experienced and capable workmen only, and must be true to line and grade. They shall be substantial and unyielding, of exact dimensions for the structure to be built, and of first-class workmanship throughout. The frame or studding must be properly braced or tied together by means of wire or rods.
The surfaces next the concrete will be oiled just after being built and oiled again just previous to placing the concrete. Forms used a second time must be carefully cleaned and oiled again. The oil to be used shall be paraffine oil, thick and heavy enough to act as a filler.
Forms must be kept moist to prevent shrinkage, as directed by the Engineer. All forms shall be so constructed as to be readily cleaned. Great care must be taken to clean sawdust, dirt or debris from the forms just before placing the concrete, and whenever necessary forms must be cleaned out with steam-jet or equally effective means satisfactory to the Engineer. Forms shall, in general, not be removed from the concrete in less than seven (7) days for columns and beam sides, ten (10) days for slab forms, and twenty-one (21) days for beam and girder bottoms, except in the case of vertical surfaces which do not carry loads. The above limits apply to work done in warm weather, from April 1 to December 1. For work done in winter, from December 1 to April 1, forms shall not be removed in less than one and one-half (1 1/2) the time as specified above. No forms whatever will be removed at any time without first notifying the Engineer, and he may increase the time for forms to remain in place if deemed necessary. The notification given the Engineer shall not be considered to relieve the Contractor of full responsibility for the construction and removal of forms.
Wherever practical, edges of beams, girders and columns will be chamfered and a "V"-shaped strip placed in all corners. All forms must be so designed so that they may be removed without damage to the concrete.
All projecting wires and bolts, or other devices that may be used for holding the forms in place and that pass through the concrete, must be cut off at least one inch beneath the finished surface and the ends covered with cement mortar of same mix as used in the body of the work.
The Contractor shall furnish a sufficient number of forms so that the work can be prosecuted rapidly, and if at any time the work is not proceeding at a rate sufficient, in the opinion of the Engineer, to complete the work in a reasonable time, a greater number of forms shall be constructed if required. If the Contractor desires, he may use steel forms in place of wood forms. Steel forms must meet the approval of the Engineer.
Placing Steel Reinforcement. - The Contractor shall furnish and imbed in the concrete square, cold-twisted bars, or deformed bars of equal net area approved by the Engineer, or plain bars of number and size shown on plans and located as shown or as directed by the Engineer. The detailed drawings show all the main reinforcement, but any minor reinforcement not shown shall be furnished and placed where considered necessary by the Engineer, without extra charge. Square twisted bars or deformed bars are to be used for all tensile reinforcement; plain square bars for hoops and "U" bars, and plain round bars for the arch reinforcement.
All steel in girders, beams, columns and walls shall be imbedded in the concrete not less than one and one-half (1 1/2) inches, in slabs not less than three-quarter (3/4) inch, and in the bottom of footing not less than three (3) inches.
Rods or bars shall be thoroughly cleaned of all kinds of dirt and scale or excessive rust, and shall be free from oil or paint. In placing bars the directions of the Engineer in regard to spacing and position in the cross-section of the concrete, for lengths, wiring, bending, etc., shall be strictly followed. Detailed drawings or other detailed information of bending and copies of steel lists shall be furnished the Engineer for approval before the work commences. Bars shall be wired together at each intersection with suitable wire ties to keep the bars in correct position, and shall be braced so as not to be displaced by their being sprung out of position or under the necessary tamping or ramming of the concrete. Special spacers and supports shall be provided to support bars in beams and girders.
Horizontal bars shall be of single length between supports. All bars in top of beams, girders and slabs over supports shall extend back from the face of the support a distance of at least 40 diameters of the bar, and in the bottom a distance of at least 20 diameters, but in no case less than 12 inches. The ends of the bars shall be bent into the form of a hook and a stub inserted in the hook if the full grip, as specified, can not be obtained. Wherever splices occur in any other manner the bars must be lapped at least 40 diameters of the bars, but never less than 12 inches.
Steel Reinforcement. - Steel used as reinforcement in concrete shall meet all the requirements of the Manufacturers' Standard Specifications for concrete reinforcement bars rolled from steel billets, as adopted in 1910, revised in 1912, with all subsequent amendments thereto.
All steel reinforcement shall be free from excessive rust, loose scale, or other coatings of any character which would reduce or destroy its bond with the concrete.