5-17. PLACING CONCRETE: Concrete shall be handled from the mixer or transport vehicle to the place of final de- posit in a continuous manner, and as rapidly as practicable, until the given unit of operation, approved by the Engineer, is completed, Concrete that has attained its initial set, or has contained its water content for more than 1 hour, shall not be deposited in the work. The concrete shall be deposited in the forms as nearly as practicable in its fin&8l position, so as to avoid rehandling. Special care shall be exercised to prevent splashing the forms or reinforcement with concrete in advance of pouring. Immediately after depositing, the concrete shall be compacted by thoroughly agitating the plastic mass in a manner approved by the Engineer, that will force out all air pockets and work the mixture into corners, around reinforcements and inserts, anc prevent the formation of voids, Concrete shall not be place on concrete which has hardened sufficiently to cause the for mation of seams and planes of weakness within the section. Concrete shall not be allowed to drop freely more than 8 fee in unexposed work, nor more than 5 feet in exposed work. Where greater drops are required, a tremie or other method approved by the Engineer shall be employed. The discharge of the tremie shall be controlled so that the concrete may be effectively compacted into horizontal layers not exceed- ing 12 inches in thickness with a minimum of lateral movement. a. Earth-Foundation Placement: b. Chute Placement: Concrete footings shall be placed upon undisturbed, clean surfaces, free from mud, standing or running water. When the foundation is on dry soil, waterproof sheathing paper shall be laid over the earth surfaces to receive the concrete, When concrete is conveyed by chute, the plant and equipment shall be of such size and design as will ensure a continuous flow of concrete in the chute. The chute shall be of metal or metal-lined wood and the different portions shall be set at approximately the same slope, which shall be not less than 1 vertical to 3 horizontal, nor more than 1 vertical to 2 horizontal. The discharge end of the chute shall be provided with a baffle to prevent segregation. If the height of the discharge end of the chute is more than 3 times the thickness of thse laye being deposited, but not more than 5 feet above the surface of the concrete in the forms, a spout shall be used, and th. lower end maintained as near the surface of deposit as prac- ticable. When the pouring operation is intermittent, the chute shall discharge into a hopper. The chute shall be thoroughly cleaned before and after each run. All waste ma- terial and the flushing water shall be discharged outside o: the forms, 5-le