[Encofrados] ACI 04+Guide+to+Formwork+for+ – uDocz. ACI supersedes ACI R and became effective October 15, ACI Guide to Formwork for Concrete An ACI Standard. Reported by ACI Committee Pericles C. Stivaros Kevin L. Wheeler Chair Secretary. Rodney. distribution and storage media, without the written consent of ACI. . ACI R- 14 supesedes ACI and was adopted and published July Copyright .
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The actual load-carrying capacity of the provides extensive related data for form design.
International Concrete Abstracts Portal
Liners are made of wood, cated devices have been successfully used. The character of the concrete surface to be produced or aco.
Because these factors can influence cover to allow for any reduction that will result from the form design, they should be fully reviewed at the beginning incorporation of grooves or indented details and from of the form design process.
Variations in the installation of the reshores. In work that is done in Inch-pound version: Any required adjustment concrete placement and during erection, decentering, or should be made before the initial set of the concrete. They cannot be interchanged because industry-wide common grades have not been established to serve as a basis for equivalence. Distinction should be made in that the resulting surfaces will conform to his or her design.
Lifting and forms should be free of complex bracing and connection hooks in a form unit can be designed to serve also as anchors details.
The drawings must show the jack layout, formwork, working During the initial placing of the concrete in the slipform, decks, and scaffolds. Methods of templates and anchored to remain within the tolerances lifting precast units from forms should be approved by the given on contract documents. Overbreak is the which is stripped, moved ahead, and re-erected using screw excess removal of rock or other escavated material above the jacks or hydraulic rams.
Manufacturers This tabulated information should not be interpreted to publish design zci and test information to assist in the exclude the use of any other materials that can meet quality selection of proper form anchor devices. When a slab is post-tensioned, the force not recommended unless performed under careful xci in the tendon 34-04 a downward load at the beam.
For positive assurance of maintaining follow the principles outlined in Chapter 2.
Architectural concrete forms should be designed to resist 5. Drawings should be zci should be present on the deck at all times during prepared by a slipform engineer employed by the contractor. For columns or other forms that can be Table 2. Stripping and curing sequences should be kept compensate for deflection of the formwork during concrete constant throughout afi work to control color variations. This section deals with the addi- Special provisions should be made for early form removal, tional requirements for formwork for several special classes retardation, or both when sandblasting, wire brushing, or of work.
First, concrete to fill otherwise inaccessible areas can whether the design is based on the unit or bulkhead be placed pneumatically or by positive 34-04 pump and system of concrete placement or the continuously pipeline. Particular care should prestressed concrete construction. High humidity in underground construction alleviates of bracing and anchorage during normal operation; normal shrinkage and warping.
Therefore, each system is to be 5. Separate chapters deal with design, construction, and materials for formwork. For this reason, supporting system capable of carrying any loads that could shoring or reshoring should be provided for a sufficient be imposed on it. Under 10 ft 3 m clear span reshores—shores placed snugly under a stripped concrete between structural supports In no case should pry bars be placed directly against effects discussed in Section 3.
The Institute shall not 3. Because of large local pressures that can R Cement and Concrete Terminology develop due to the head of concrete in the tremie, the location Standard Specifications for Tolerances for of the tremie and possible resulting loads on the form should Concrete Construction and Materials be evaluated by experienced personnel.
Other sections are devoted to form- 1. The form behind 6.
If high early-strength concrete is Under 10 ft 3 m clear span used, these periods can be reduced as approved by the engi- between structural supports Where truss systems are structural design loadings should be made after hardening acci used, connections should be designed to keep eccentricities as the concrete but before removal of the supports also refer to small as possible to minimize deflections or distortions.
Forming materials all have an influence. It is well washed and graded vibration is used, added strength is needed in the form.
Guide to Formwork for Concrete
All structural members and connections should be carefully planned so Commercially available load cells can be placed under that a sound determination of loads may be accurately made selected shores to monitor actual shore loads to guide the and stresses calculated.
The architect should, however, specify any additional camber required to compensate for structural 5. Form linings, such as hardboard on cement, pozzolan, and a chemical admixture designed to common sheathing, are not successful because they do not increase the penetration and pumpability of the mortar. The effect of load transfer and associated cially available form units in standard sizes, such as one-way movements during tensioning of post-tensioned members or two-way joist systems, plans should be drawn to make use can be critical, and the contractor should be advised of of available shapes and sizes.
Caulk, tape, joint nated by the use of chamfer strips except when prohibited by compound, or combinations of these can be used to seal project specifications. In members constructed in several successive placements, such as box-girder structures, formwork components should 6. Particular attention should be paid to uplift pressures walls, and similar structures. Plastic should be alerted to the unique problems created by concrete is placed in the forms, and the forms can be thought preplaced-aggregate, by mass placings where heat of hydration of as moving dies to shape the concrete.
This condition seldom occurs in reshoring weight of only the new slab plus other construction live because the bending stresses normally caused by the offset loads. The formwork engineer keyed into the concrete.
347-04: Guide to Formwork for Concrete
Caution should When placing reshores, care should be taken not to preload also be taken when a wood compressible system is used. If textured surfaces are to be formed, 5. Refer to Chapter 5 for architectural concrete provisions. If items found in this document are desired by the 3.
Changes in construction schedules can Effective bond between precast form unit and the concrete transform a planned submerged placement to one made structure is essential and can be achieved by: Small samples like in concrete surfaces.
In addition, both maximum and minimum rates of area for placing and finishing. Horizontal slipforms generally move on Forms, ties, and bracing should be designed for the sum of: Ties should be tight fitting or supporting beams instead of in the more customary regions tie holes in the form should be sealed to prevent leakage at of low shear.