ACI 543R-00 Design, Manufacture, and Installation of Concrete Piles.
4.1—General Established plants or casting yards currently manufacture most precast concrete piles, although job-site casting yards can be used for large projects. Modern production methods and quality controls developed by the manufacturers gener- ally ensure high-quality products and usually require less control and field inspection than normal on-site work. Estab- lished prestressed- or precast-concrete manufacturing plants are often certified by the Precast/Prestressed Concrete Insti- tute (PCI) or the International Conference of Building Offi- cials (ICBO), or both, thereby providing recognizable quality control. Certain minimum requirements and basic construction procedures should be established so that the design require- ments for quality, strength, and durability will be realized for all conditions, whether the piles are produced in an estab- lished precasting plant or by job-site casting. Engineers should consider specifying that, at a minimum, precast pre- stressed concrete manufacturing plants have a quality-con- trol program that is equivalent to that established by PCI Manual 116. Engineers should consider requiring inspection of the prestressing plant during fabrication of the piles by personnel knowledgeable in pile fabrication. 4.2—Forms 4.2.1 General requirements—Formwork should adhere to the requirements given in ACI 347R and Chapter 6 of ACI 318-95, except as modified herein.
4.2.2 Type—Forms should be suitably permanent — met- al, plastic, or concrete constructed — so that the tolerances given in Section 4.6.3 can be maintained. Wood forms can be used for short runs of special shapes and should be construct- ed to produce work of a quality equal to that produced by per- manent-type forms. In all cases, a concrete foundation for the casting bed is recommended. All forms for prestressed-con- crete piles should be constructed to permit movement of the member during release of the prestressing force without damage. Avoid offsets at form joints due to misalignment or an open joint. Fins or offsets in the cast pile can cause stress concentrations, which in some instances have caused shal- low cracks to form in the concrete. Grinding of the form sur- faces may be required to correct offsets. Leaky joints should be sealed with pressure-sensitive waterproof tape. Pans or trough-type forms can have a slight taper or draft to the vertical sides to facilitate stripping. A maximum draft or taper of 1/4 in./ft (20 mm/m) on each vertical side will generally be acceptable, provided that the cross-sectional area of the pile is not less than the specified section with true vertical sides. Slipforming can be used for the manufacture of precast piles for both solid and hollow cross sections. Hollow piles can be formed by a traveling mandrel and top form or screed. Solid sections require a traveling top form only. In both cas- es, the lower half of the pile section is formed by a fixed mold of conventional design. The traveling mandrel and screed should be metal and have smooth surfaces. The designer should be assured that the method of controlling the concen- tricity of the mandrel, strand, spiral, and reinforcement loca- tions is adequate for the job requirements (see Sections 4.2.5, 4.5.3, and 4.6.3 for other discussion).ACI 543R pdf download.