[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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Skip to main content. Log In Sign Up. Wheeler Chair Secretary Rodney D. Kirk Gregory Donald M.
Jum Horst William R. Thomas Scott William A. Johnston Aviad Shapira Jeffrey C. Erson Dov Kaminetzky Rolf A. John Gardner Harry B. A section on contract documents explains the kind and Preface, p. Separate chapters deal with design, construction, and materials for formwork. Considerations peculiar to architectural concrete 1. Other sections are devoted to form- 1. The Institute shall not 3. Reference to this document shall afi be made in contract 3.
If items found in this document are desired by the 3. ACI does not make any 4.
The user must determine the applicability of all regulatory limitations before applying the ACI supersedes ACI R and became effective October 15, 374-04 Now comprising more than pages, this is the Chapter 5—Architectural concrete, p.
The Japan National Council on Concrete has 5. Therefore, each system is to be 5. Combining values from the 5. Chapter 6—Special structures, p. This is 3347-04 to be 8. The first report by the committee, based on a survey of construction loads from above. Also test reports and design formulas for determining lateral pressure called blowholes.
The major result of this study and centering—specialized temporary support used 347-4 the report was the development of a basic formula establishing construction of arches, shells, and space structures where the form pressures to be used in the design of vertical formwork. Two subsequent revisions, of the structure. ACI R and ACI R, were committee reports climbing form—a form that is raised vertically for because of changes 34704 the ACI policy on the style and format succeeding lifts of concrete in a given structure.
ACI returned the guide to the standard- diagonal bracing—supplementary formwork acci ization process. Historically, the term has been the dimensions of footings, columns, and beams should applied to floor forming systems. Variations in the installation of the reshores. Wherever possible, suspended and its supporting structure used for supporting depressions in the tops of slabs should be made without workers, tools, and materials; adjustable metal scaffolding can a corresponding break in elevations of the soffits of be used for shoring in concrete work, provided its structure has slabs, beams, or joists; the necessary load-carrying capacity and structural integrity.
For formwork drawings; bids for the work. Unnecessarily exacting requirements can b. For the formwork before concreting and during make bidders question the specification qci a whole and make concreting; and it difficult for them to understand exactly what is expected.
Who will give such reviews, approvals, or both. They can be overly cautious and overbid or misinterpret 1. The basic geometry of such materials and such other features necessary to attain the objec- structures, as well as their required camber, should be tives. 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 34-704 to make use can be critical, and the contractor should be advised of of available shapes and sizes.
Refer to Section 3. Formwork should also be the structural plans because they can play a key role in designed so that it will safely support all vertical and lateral the structural design of the form.
Responsibility for the design of the formwork rests before construction begins. The amount of planning required with the contractor or the formwork engineer hired by the will depend on the size, complexity, and importance consid- contractor to design and be responsible for the formwork.
Formwork should be designed for 2. System stability and member ciencies that can lead to failure are: Accordingly, in communication of the loads, it should be clear whether they are service acci or factored loads. The weight of adi plus the weight of the does not relieve the contractor of the responsibility for reinforcement and freshly placed concrete is dead load. The adequately constructing and maintaining the forms so that live load includes the weight of the workers, equipment, they will function properly.
If reviewed by persons other material storage, runways, and impact. Refer to Section 2. When major design values and loading conditions should be shown motorized carts are used, the live load should not be less than on formwork drawings. Minimum values given for and connection details, formwork drawings should provide other pressure formulas do not apply to Eq.
For columns or other forms that can be Table 2.
For walls with a rate of placement of less than 2. Accessory Safety factor Type of construction Imposition of any construction loads on the partially Form tie 2. When fabricated formwork, shoring, or surge pressure.
For formwork for pressure should be considered when using external materials that will experience substantial reuse, reduced values vibration or concrete made with shrinkage compensating or should be used. For formwork materials with limited reuse, expansive cements. Pressures in excess of the 34704 allowable stresses specified in the appropriate design codes or hydrostatic head can occur. Where there will be a 7.
Wind loads on enclosures or other wind breaks attached to the formwork should be 2. For wall the loads transmitted to the floors, shores, and reshores or forms exposed to the elements, the minimum wind design backshores as a result of the construction sequence.
Bracing for The analysis should consider, but should not necessarily wall forms should be designed for a horizontal load of at least be limited to: 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.
If plywood or used to support formwork and other construction loads. It lumber splices are made for timber shoring, they should be should be kept in mind that the strength of freshly cast slabs designed to prevent buckling and bending of the shoring.
Before construction, an overall plan for scheduling of Formwork failures can be attributed to substandard materials shoring and reshoring or backshoring, and calculation of and equipment, human error, and inadequacy in design. The plan and responsi- Construction procedures should be planned in advance to bility for its execution remain with the contractor.
Some of the safety provisions that should 2. Horizontal lacing can be considered displacement or failure. A supply of extra shores or in design to hold in place and increase the buckling strength other material and equipment that might be needed in of individual shores and reshores or backshores.
The braced system should be anchored to ensure all forms that will be crane-handled. This is especially stability of the total system.
In the case of wall formwork, consideration should be given to an 2. No concrete should be fall protection devices, such as personal fall arrest systems, placed on formwork supported on frozen ground.
Lacing to reduce the shore slenderness ratio can be to Fig. All threads should fully work include: By doing this, each supported directly on the formwork or structural member. The formwork at control joints should be left undisturbed when forms are should be suitable for the support of such runways without stripped and removed only after the concrete has been significant deflections, vibrations, or lateral movements.
Wood strips inserted for architectural 3. Loads, such as aggregate, 3. Specifying tolerances more exacting than needed can work drawings. Both before each use.
If surface appearance is important, forms should ances are not specified or shown. Specifying tolerances more stringent 3. For example, specifying 3470-4 3. Where a project involves to damage or overload it. Improper positioning of shore from floor to floor can create bending stresses for which the slab was not designed.
In measuring irregularities, the straightedge or template Class of surface can be placed anywhere on the surface in any direction. The project specifications should Class C is a general standard for permanently exposed clearly state 347-40 a permitted variation in one part of the surfaces where other finishes are not specified.
Class D is a construction or in one section of the specifications should not minimum-quality requirement for surfaces where roughness be construed as permitting violation of the more stringent is not objectionable, usually applied where surfaces will be requirements for any other part of the construction or in any permanently concealed. Special limits on irregularities can other such specification section.
If permitted irregularities are nating the tolerances for concrete work with the tolerance different from those given in Table 3. Allowable stresses and punching shear. The reversal of stresses results irregularities are 34-704 either abrupt or gradual. Offsets from the reversal of bending moments in the slab over the and fins resulting from displaced, mismatched, or misplaced shore or reshore below as shown in Fig.
Where the forms, sheathing, or liners, or from defects in forming materials conditions are questionable, the shoring location should be are considered abrupt irregularities. If reshores do not align from warping and similar uniform variations from planeness with the shores above, then calculate for reversal stresses.