03100 Concrete Formwork by lanyuehua


									 1                                             S E CT IO N 03100
 2                                       CONCRETE FORMWORK


 4   1.01    DESCRIPTION

 5       A. Scope of Work: This Section specifies all labor, materials and equipment necessary for
 6          providing and installing formwork for concrete.

 7       B. Related Work Described Elsewhere:
 8          1. Section 03200 "Concrete Reinforcement"
 9          2. Section 03300 "Cast-in-Place Concrete"

10       C. General Design: The Contractor shall be responsible for the design of all formwork and
11          for safety in its construction, use and removal.


13       A. Qualifications: Formwork shall be constructed in accordance with the specified standards, as
14          well as all pertinent codes and regulations. In cases where requirements of pertinent codes
15          conflict with the requirements of these specifications, the more stringent shall govern.

16       B. Standards: Unless otherwise indicated, all materials, workmanship and practices shall
17          conform to the following standards:
18          1. Standard Building Code
19          2. ACI 347 "Recommended Practice for Concrete Formwork"
20          3. Local codes and regulations


22       A. Submittals shall be submitted to the County/Professional for review and acceptance prior
23          to construction in accordance with the General Conditions and specifications Section
24          01300 "Submittals."

25       B. Materials: Submit manufacturer's literature on form ties, spreaders, corner formers, form
26          coatings and bond breakers.


28   2.01    GENERAL

29       A. All material supplied shall be one of the products specified in Appendix D "List of
30          Approved Products" appended to these technical specifications.

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     OCU Master CIP Technical Specifications                                            rev: August, 2012
 1   2.02    MATERIALS

 2       A. Form Lumber: Use form lumber when in contact with exposed concrete, conforming to
 3          the following or acceptable equivalent.

 4       B. Lumber: Douglas Fir/Larch No. 2 grade, seasoned, surfaced on four sides.

 5       C. Plywood: "Plyform", Class I or II, bearing the label of the Douglas Plywood Association.
 6          (Minimum 3/4-inch thickness).

 7       D. Form Ties: Use form ties which do not leave an open hole through the concrete and
 8          which permit neat and solid patching at every hole. Use embedded rods with integral
 9          waterstops and cones to provide a 1-inch breakback. Wire ties and wood spreaders will
10          not be permitted.

11       E. Form Coatings: Form release coating shall be a paraffin base oil or mineral oil coating
12          which effectively prevents absorption of moisture; prevents bonding with concrete; is
13          non-staining to concrete; and leaves the concrete with a paintable surface.

14       F. Chamfer Strips: Chamfer strips shall be polyvinyl strips or acceptable equal, designed to
15          be nailed in the forms to provide a 3/4-inch chamfer (unless indicated otherwise) at
16          exposed edges of concrete members.


18   3.01    INSTALLATION

19       A. Construction of Formwork: Forms shall be sufficiently strong to withstand the pressure
20          resulting from the placement and vibration of concrete and shall be sufficiently rigid to
21          maintain specified tolerances. Forms shall be sufficiently tight to prevent loss of mortar,
22          and shall be adequately braced against lateral, upward or downward movement.

23       B. Coating of Forms: Apply form coating to board forms prior to placing reinforcing. Keep
24          form coatings off steel reinforcing, items to be embedded, and previously placed concrete.

25       C. Form Erection:
26          1. Provide a means of holding adjacent edges, ends of panels, and ends of sections
27             tightly together and in accurate alignment so as to prevent the formation of ridges,
28             fins, offsets, or similar surface defects of the finished concrete. Insure that forms may
29             be removed without damage to the surface of the finished concrete.
30          2. Provide a positive means of adjustment of shores and struts. Insure that all settlement
31             is taken up during concrete placing.
32          3. Temporary openings shall be provided in wall forms to limit the free fall of concrete to a
33             maximum of 6-feet unless an elephant trunk is used. Such openings shall be located to
34             facilitate placing and consolidation and shall be spaced no more than 8-feet apart.
35             Temporary openings shall also be provided in the bottom of the wall, column forms, and
36             elsewhere as necessary to facilitate cleaning and observation immediately prior to
37             placing.

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     OCU Master CIP Technical Specifications                                             rev: August, 2012
 1           4. Do not embed any form-tying device or part thereof other than metal in concrete.
 2           5. Form surfaces of concrete members except where placement of the concrete is against
 3              the ground. The dimensions of concrete members shown on the Drawings apply to
 4              formed surfaces, except where otherwise indicated.

 5       D. Form Reuse: Reuse only forms which maintain a uniform surface texture on exposed
 6          concrete surfaces. Apply light sanding between uses to obtain such a uniform texture.
 7          Plug unused tie rod holes with corks, shave flush, and sand the concrete surface side of
 8          the plug.

 9       E. Removal of Forms
10          1. Forms and shoring for elevated structural slabs, girders, and/or beams shall remain in
11             place until the concrete has reached a compressive strength equal to the specified 28-
12             day compressive strength as determined by test cylinders. Do not remove supports
13             and re-shore. The following table indicates the minimum allowable time after the last
14             concrete is placed before forms, shoring, and/or bracing may be removed.
            Structural Item                                      Minimum Allowable Time
                                                                 When concrete reaches specified
            Bottom side of slabs, girders, beams
                                                                 28-day compressive strength
            Vertical sides of girders, beams                     48-hours
            Walls not supporting vertical or horizontal loads    48-hours
                                                                 When concrete reaches specified
            Walls supporting vertical or horizontal loads
                                                                 28-day compressive strength
            Footings, pipe encasements, pipe supports            24-hours
18           2. Do not remove forms from concrete which has been placed with outside air
19              temperature below 50° F without first determining if the concrete has properly set
20              regardless of the minimum times specified in the table above. Do not apply heavy
21              loading on recently poured concrete. Immediately after forms are removed, the
22              surface of the concrete shall be carefully examined and any irregularities in the
23              surface shall be repaired and finished as specified.

24       F. Formed Openings: Openings shall be of sufficient size to permit final equipment
25          alignment without deflection or offsets of any kind. Where the items pass through the
26          wall, allow space for packing to ensure watertightness. Provide openings with
27          continuous keyways with waterstops where required. Provide a slight flare to facilitate
28          grouting and the escape of entrained air during grouting. Provide reinforcement as
29          indicated and specified. Reinforcing steel shall be at least 2-inches clear from the
30          opening.

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     OCU Master CIP Technical Specifications                                          rev: August, 2012
 1       G. Embedded Items: Set anchor bolts and other embedded items accurately and hold
 2          securely in position in the forms until the concrete is placed and set. Check all special
 3          castings, channels, or other metal parts that are to be embedded in the concrete prior to
 4          and again after concrete pour. Check all nailing, blocks, plugs, and strips necessary for
 5          the attachment of trim, finish, and similar work prior to concrete pour.

 6       H. Pipes and Wall Spools Cast in Concrete
 7          1. Install wall spools, wall flanges, and wall anchors before placing concrete. Do not
 8             weld, tie or otherwise connect the wall spools to the reinforcing steel.
 9          2. Support pipe and fabricated fittings to be encased in concrete on concrete piers or
10             pedestals. Carry concrete supports to firm foundations so that no settlement will be
11             possible during Construction.

12       I. Form Tolerances
13          1. Failure of the forms to produce the specified concrete surface tolerance shall be
14             grounds for rejection of the concrete work. Rejected Work shall be repaired or
15             replaced at no cost to the County.
16          2. The following table indicates tolerances or allowable variations from dimensions or
17             positions of structural concrete work:
                                                         Maximum Tolerance
                   Sleeves and inserts                   +1/4-inch to -1/4-inch
                   Projected ends of anchors             +1/4-inch to -0.0-inch
                   Anchor bolt setting                   +1/4-inch to -1/4-inch
                   Finished concrete                     + 1/4-inch to -1/4-inch in 10 feet of length

20               The planes or axes from which the above tolerances are to be measured shall be as
21               follows:
                   Sleeves and inserts           Centerline of sleeve or insert
                                                 Plane perpendicular to the end of the anchor as located
                   Projected ends of anchors
                                                 on the Drawings
                   Anchor bolt setting           Centerline of anchor bolts
                   Finished concrete             The concrete surface as located on the Drawings
24           3. Where equipment is to be installed, comply with manufacturer's tolerances if more
25              stringent than above.

27                                             END OF SECTION

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     OCU Master CIP Technical Specifications                                              rev: August, 2012

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