6 4 GUIDE TO FORMWORK FOR CONCRETE (ACI 374R-14) 3.2 Contract documents The contract documents should set forth the tolerances required in the finished structure but should not attempt to specify the means and methods by which the formwork engineer/contractor designs and builds the formwork to achieve the required tolerances. The layout and design of the formwork should be a joint effort of the formwork engineer and the formwork contractor. The formwork construction in compliance with the formwork design is the responsibility of the formwork contractor. When formwork design is not by the contractor, formwork design is the responsibility of the formwork engineer. This approach gives the necessary freedom to use skill, knowledge, and innovation to safely construct an economical structure. By reviewing the formwork drawings, the engineer/architect can understand how the formwork engineer/contractor has interpreted the contract documents. Some local jursidictions have legal requirements defining the specific responsibilities of the engineer/architect in formwork design, review, or approval Individual specifications The specification for formwork will affect the overall economy and quality of the finished work; therefore, it should be tailored for each particular job, clearly indicate what is expected of the contractor, and ensure economy and safety. A well-written formwork specification tends to equalize bids for the work. Vague or overly restrictive requirements can make it difficult for bidders to understand exactly what is expected. Bidders can be overly cautious and overbid or misinterpret requirements and underbid. Using standard specifications such as ACI 301 that have many input sources in development can mitigate these possible problems. A well-written formwork specification is of value not only to the owner and the contractor, but also to the field representative of the engineer/architect, approving agency, and the subcontractors of other trades. Some requirements can be written to allow discretion of the contractor where quality of finished concrete work would not be impaired by the use of alternative materials and methods. Consideration of the applicable general requirements suggested herein are not intended to represent a complete specification. Requirements should be added for actual materials, finishes, and other items peculiar to and necessary for the individual structure. The engineer/architect can exclude, call special attention to, strengthen, or make more lenient any general requirement to best fit the needs of the particular project. Further detailed information is given in ACI SP Formwork materials and accessories If the particular design or desired finish requires special attention, the engineer/architect can specify in the contract documents the formwork materials and any other feature necessary to attain the objectives. If the engineer/architect does not call for specific materials or accessories, the formwork engineer/ contractor can choose any materials that meet the contract requirements. When structural design is based on the use of commercially available form units in standard sizes, such as one- or two-way joist systems, plans should be drawn to make use of available shapes and sizes. Some variation from normal tolerances should be permitted by the specification: a) for connections of form units to other framing; and b) to reflect normal installation practices and typical used condition of the form type anticipated Finish of exposed concrete Finish requirements for concrete surfaces should be described in measurable terms as precisely as practicable. Refer to 5.4, Chapter 7, and ACI 347.3R Design, inspection, review, and approval of formwork Although the safety of formwork is the responsibility of the contractor, the engineer/architect or approving agency may, under certain circumstances, decide to review and approve the formwork, including drawings and calculations. If so, the engineer/architect should call for such review or approval in the contract documents. Approval might be required for unusually complicated structures, structures whose designs were based on a particular method of construction, structures in which the forms impart a desired architectural finish, certain post-tensioned structures, folded plates, thin shells, or long-span roof structures. The following items should be clarified in the contract documents: a) Who will design the formwork b) Who will determine post-tensioning sequence and support needed for redistribution of loads resulting from stressing operations c) Who will design shoring and the reshoring system d) Who will inspect the specific feature of formwork and when will the inspection be performed e) What reviews, approvals, or both, will be required for: i. Formwork drawings, calculations, or both ii. Post-tensioning support iii. Reshoring design iv. Formwork preplacement inspection f) Who will give such reviews, approvals, or both Contract documents The contract documents should include all information about the structure necessary for the formwork engineer to design the formwork and prepare formwork drawings and for the formwork contractor to build the formwork such as: a) Number, location, and details of all construction joints, contraction joints, and expansion joints that will be required for the particular job or parts of it b) Sequence of concrete placement, if critical (examples include pour strips and hanging floors) c) Tolerances for concrete construction d) The live load and superimposed dead load for which the structure is designed and any live-load reduction used e) Intermediate supports under stay-in-place forms, such as metal deck used for forms and permanent forms of other materials supports, bracing, or both, required by the structural engineer s design for composite action; and any other special supports f) The location and order of erection and removal of shores for composite construction American Concrete Institute Copyrighted Material
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4.3.5 - Breakaway Walls Elevation of a structure on a properly designed foundation reduces the potential for water damage from flooding. When the space below the lowest elevated floor is maintained free
PDCA Driven-Pile Terms and Definitions This document is available for free download at piledrivers.org. Preferred terms are descriptively defined. Potentially synonymous (but not preferred) terms are identified 2ff7e9595c
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