LD7_GW_03_11_13.00_10_Structural_Cast_in_Place_Concrete_Forming.pdf

Lock and Dam 7 Guidewall Crib Repair

SECTION TABLE OF CONTENTS

DIVISION 03 - CONCRETE

SECTION 03 11 13.00 10

STRUCTURAL CAST-IN-PLACE CONCRETE FORMING

PART 1 GENERAL

1.1 REFERENCES

1.2 SYSTEM DESCRIPTION

1.3 SUBMITTALS

PART 2 PRODUCTS

2.1 FORM MATERIALS

2.1.1 Forms For Class D Finish

PART 3 EXECUTION

3.1 INSTALLATION

3.1.1 Formwork

3.2 FORM REMOVAL

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SECTION 03 11 13.00 10 Page 1

SECTION 03 11 13.00 10

STRUCTURAL CAST-IN-PLACE CONCRETE FORMING

PART 1 GENERAL

1.1 REFERENCES

The publications listed below form a part of this specification to the extent referenced. The publications are referred to within the text by the basic designation only.

ACI INTERNATIONAL (ACI)

ACI 347 (2004; Errata 2008) Guide to Formwork for Concrete

1.2 SYSTEM DESCRIPTION

The design, engineering, and construction of the formwork is the responsibility of the Contractor. Design formwork in accordance with methodology of ACI 347 for anticipated loads, lateral pressures, and stresses, and capable of withstanding the pressures resulting from placement and vibration of concrete. Design the formwork as a complete system with consideration given to the effects of cementitious materials and mixture additives such as fly ash, cement type, plasticizers, accelerators, retarders, air entrainment, and others. Monitor the adequacy of formwork design and construction prior to and during concrete placement as part of the Contractor's approved Quality Control Plan. Submit design analysis and calculations for form design and methodology used in the design. Allow at least 15 days either before fabrication on site or before delivery of prefabricated forms for government review.

1.3 SUBMITTALS

Government approval is required for submittals with a "G" designation;

submittals not having a "G" designation are for information only. When used, a designation following the "G" designation identifies the office that will review the submittal for the Government. Submit the following in accordance with Section 01 33 00 SUBMITTAL PROCEDURES:

SD-02 Shop Drawings

Formwork; G, STR

SD-03 Product Data

Design; G, STR Form Materials; G, STR

SD-06 Test Reports

Inspection; G Formwork Not Supporting Weight of Concrete; G.

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PART 2 PRODUCTS

2.1 FORM MATERIALS

Submit manufacturer's data, including literature describing form materials, and accessories, structural design calculations, shop drawings, erection sequencing and details, layout drawings, attachment details, hardware to be left in place and any other information to fully describe the proposed forming system. The formwork system shall be designed and installed to fit around or fit tight against any variations, gaps or extrusions in or from the existing crib and concrete surfaces.

2.1.1 Forms For Class D Finish

Forms for Class D finished surfaces, except where concrete is placed against earth, shall be wood or steel or other approved concrete form material.

PART 3 EXECUTION

3.1 INSTALLATION

3.1.1 Formwork

Forms shall be constructed true to the structural design and required alignment. Formwork shall be designed and installed in such a manner to contain all low density cellular concrete during each placement. Forms shall be mortar tight, properly aligned and adequately supported to produce concrete surfaces generally flush with the existing exterior plane of the guidewall timber crib. Where the existing plane of the cribwall is not intact, the forms shall meet the surface requirements and conform to construction tolerance given in TABLE 1. Continuously monitor the alignment and stability of the forms during all phases to assure the finished product will meet the required surface class or classes specified. Failure of any formed concrete surface either due to surface texture, deflection or form collapse shall be the responsibility of the Contractor as will the replacement or correction of unsatisfactory surfaces. When forms for continuous surfaces are placed in successive units, care shall be taken to fit the forms over the completed surface to obtain accurate alignment of the surface and to prevent leakage of mortar.

Forms shall not be re-used if there is any evidence of defects which would impair the quality of the resulting concrete surface. All surfaces of used forms shall be cleaned of mortar and any other foreign material before reuse. The forms shall be designed to seal tightly to various bottom conditions such as rock, silt, hardpan, etc. at varying elevations. Rock or riprap at the base of the crib shall not be disturbed. Minor trimming or cutting of protruding crib members will be permitted to allow installation of the forms within the tolerances described in TABLE 1 below. Trimming or cutting of the crib members greater than 2 inches shall not be permitted, except as approved by the Contracting Officer. Submit drawings showing details of formwork, including dimensions of joints, supports, studding and shoring, and sequence of form and shoring removal. Submit form erection methods to allow the displacement of river water during the placement of low density cellular concrete.

SECTION 03 11 13.00 10 Page 3

3.2 FORM REMOVAL

All forms shall be completely removed before project completion. Forms shall be removed in a manner which prevents injury to the concrete and ensures the complete safety of the structure. Forms shall not be removed before a compressive strength test result (See Section 03 60 70.00) shows a minimum of 75% of the specified compressive strength is achieved or before seven days after placement, whichever is longer. Any additional concrete compressive strength cylinders and tests the contractor chooses to perform to determine acceptable form removal, beyond those described in Section 03 60 70.00, shall be at no additional cost to the Government. Where forms support more than one concrete placement, the forms shall not be removed until this form removal criteria is met by all supported concrete placements. The Contractor may request permission to use maturity instrumentation instead of control cylinders to determine the compressive strength of the concrete. ASTM C 1074 procedures shall be used for estimating concrete strength by means of the maturity method. All expenses associated with instrumentation of the concrete and evaluating the strength using maturity relationships shall be the responsibility of the Contractor at no additional cost to the Government.

TABLE 1

TOLERANCES FOR FORMED SURFACES

1. Variations from the plumb:

a. In the lines and surfaces of columns, piers, walls and in arises

1/4 inch in any 10 feet of length Maximum for entire length i2. Variation for the level or from the grades indicated on the drawings:

a. In the lines and surfaces of columns, piers, walls and in arises

1/4 inch in any 10 feet of length 3/8 inch in any bay or in any 20 feet of length Maximum for entire length -- 3/4 inch

3. Variation of the linear building lines from established position in plan

1/2 inch in any 10 feet 1 inch maximum

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