Founded in 1986, the Tilt-Up Concrete Association (TCA) strives to improve the quality and acceptance of site-cast Tilt-Up construction - one of the fastest growing industries in the United States, combining the advantages of reasonable cost with low maintenance, durability, speed of construction and minimal capital investment. Over 10,000 buildings, enclosing more than 650 million square feet, are constructed each year using this construction method.
This guide specification is provided in CSI 3-part format, and must be edited by a design professional before issue. For more information, please call us at (319) 895-6911.
THE TILT-UP CONCRETE ASSOCIATION’S (TCA) GUIDELINE SPECIFICATIONS
Standard 3-part CSI Format
SECTION 03470 – SITE CAST TILT-UP CONCRETE
This publication is intended for the use of professional personnel competent to evaluate the limitations of its content and who will accept responsibility for the application of its contents. It necessarily addresses the specification of site cast Tilt-Up construction of a general nature.
The professional using this publication is solely responsible for the application of its content to project documents, and for determining when its content is not applicable. The Tilt-Up Concrete Association makes no representation, warranty, or guarantee in connection with this publication, and expressly disclaims any and all responsibility for the accuracy or application of this guideline, and for any loss or damage resulting from its use.
The Tilt-Up Concrete Association is not undertaking to meet the duties of employers, manufacturers or suppliers to properly train, warn, and equip their employees, or others, and to comply with applicable federal, state or local regulations or laws.
The original Tilt-Up Concrete Association (TCA) "Guideline Specification for Tilt-Up Concrete Construction" was drafted and offered in 1994. TCA issued revised specifications in 2002 to incorporate the current State-of-the-Art practices for site cast Tilt-Up panels. TCA has now issued this revision to its general specification document to incorporate the improved technology that has been made available to the market over the past decade and to address important quality assurance opportunities available to the project team.
Substantial changes occur in this document throughout including the addition of tolerances, grades of finish, sandwich panel values and revised quality control requirements among others. The Specifier is instructed to review this document thoroughly taking care to notice areas that have been added to offer choices to the project based on the specific architectural or performance requirements for the intended construction.
The TCA has provided additional comments and key information throughout this document that may be deemed necessary for the inclusion in section 03470 or other key sections. This commentary is not to be considered a part of the standard specification unless added within the specification proper.
Part 1 - GENERAL
1.1 SECTION INCLUDES
- Work Included: Provide labor, materials and equipment necessary to complete the work of this Section, including but not limited to the following.
- Site-cast tilt-up concrete panels.
- Site-cast tilt-up insulated sandwich concrete panels.
- Related Work: The following items are not included in this Section and are specified under the designated Sections:
- Section 033000 – Cast-in-Place Concrete: Requirements for slab-on-grade design and construction and general requirements for concrete used in tilt-up panels.
- Section 076200 – Sheet Metal Flashing and Trim: Flashing to adjacent materials.
- Section 099000 – Painting and Coating: Site-finishing of panels as applicable.
- Reference Standards: Comply with applicable provisions of the following standards and regulations:
- AWS D1.1 - Structural Welding Code – Steel.
- AWS D1.4 - Structural Welding Code – Reinforcing Steel.
- ASTM A123/A123M – Standard Specification for Zinc (Hot-Dip Galvanized) Coatings on Iron and Steel Products.
- ASTM A184/A184M - Standard Specification for Welded Deformed Steel Bar Mats for Concrete Reinforcement.
- ASTM A185 - Standard Specification for Welded Steel Wire Fabric for Concrete Reinforcement.
- ASTM A496 - Standard Specification for Deformed Steel Wire for Concrete Reinforcement.
- ASTM A497 - Standard Specification for Steel Welded Wire Reinforcement, Deformed, for Concrete.
- ASTM A615/A615M - Standard Specification for Deformed and Plain Carbon-Steel Bars for Concrete Reinforcement.
- ASTM A706/A706M – Standard Specification for Deformed and Plain Low-Alloy Steel Bars for Concrete Reinforcement
- ASTM C31/C31M - Standard Practice for Making and Curing Concrete Test Specimens in the Field.
- ASTM C33 - Standard Specification for Concrete Aggregates.
- ASTM C39 - Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens.
- ASTM C78 - Standard Test Method for Flexural Strength of Concrete (Using Simple Beam with Third-Point Loading).
- ASTM C94/C94M - Standard Specification for Ready-Mixed Concrete.
- ASTM C143/C143M - Standard Test Method for Slump of Hydraulic-Cement Concrete.
- ASTM C150 - Standard Specification for Portland Cement.
- ASTM C293/C293M - Standard Test Method for Flexural Strength of Concrete (Using Simple Beam With Center-Point Loading).
- ASTM C309 - Standard Specification for Liquid Membrane-Forming Compounds for Curing Concrete.
- ASTM C330/C330M - Standard Specification for Lightweight Aggregates for Structural Concrete.
- ASTM C595/C595M - Standard Specification for Blended Hydraulic Cements.
- ASTM C989/C989M - Standard Specification for Slag Cement for Use in Concrete and Mortars.
- ASTM C1157/C1157M - Standard Performance Specification for Hydraulic Cement.
- ASTM C1697 - Standard Specification for Blended Supplementary Cementitious Materials.
- ACI 117 - Specifications for Tolerances for Concrete Construction and Materials.
- ACI 301 - Specifications for Structural Concrete for Buildings.
- ACI 305 - Specification for Hot Weather Concreting.
- ACI 306 - Guide to Cold Weather Concreting.
- ACI 315 - Standard for Details and Detailing Concrete Reinforcement.
- ACI 318 - Building Code Requirements for Structural Concrete.
- ACI 551 - Guide to Tilt-Up Concrete Construction.
- CRSI Manual of Standard Practice and CRSI Specifications for Placing Reinforcement.
- BSR/ASHRAE/IESNA 90.1.
- ASHRAE Handbook of Fundamentals.
- ASCE 37 – Design Loads on Structures During Construction.
- Tilt-Up Concrete Association Wind Bracing Guidelines (TCA).
- Tilt-Up Concrete Association Erection Safety Procedures Brochure (TCA).
- Submit under provisions of Section 013000.
- Shop Drawings: Submit panel shop drawings and erection drawings detailing the Work of this Section including temporary bracing. Reinforcing bars shown on the project drawings do not allow for lifting and erection stresses. Shop drawings shall be stamped by a structural engineer licensed in the jurisdiction of the project and responsible for their preparation. Include the following:
- Concrete mix designs for each mix specified.
- Mix design for structural grout for panel supports.
- Verification Samples for Exposed Finishes: Prior to construction of mock-up submit representative samples of exposed finishes for review. Samples shall be cast vertically and be approximately 18 by 18 by 2 inches in size.
- Quality Control Submittals:
- Product Data: For each product, including bond breakers, joint sealants, insulation, connection devices.
- Manufacturer’s Instructions: For manufactured items used, submit the manufacturer’s current recommended methods of installation, including relevant limitations and safety precautions.
- Test Reports: Submit certified laboratory test reports confirming physical characteristics of materials used in the performance of the Work of this Section.
1.3 QUALITY ASSURANCE
- Regulatory Requirements: Comply with applicable codes and regulations of governmental agencies having jurisdiction. Where those requirements conflict with this Specification, comply with the more stringent provisions.
- Qualifications for Tilt-Up Contractors: Contractor performing the tilt-up operations shall demonstrate the experience and expertise required to manage and execute the specified work.
- Provide certification that supervisor to be employed in the Work has been ACI certified, meeting Site Cast Tilt-Up Supervisor qualifications.
- Designer/Specifier Note: The Tilt-Up Concrete Association (TCA) has established individual and company certification programs. The Tilt-Up Certified Company program is administered by the TCA. The Tilt-Up Supervisor Certification Program is administered through ACI and is referenced in ACI 301. Delete subparagraph 1 above only if there are not enough companies meeting this qualification in the location of the project.
- Qualifications for Field Personnel: Contractor shall show evidence of competence in site cast tilt-up concrete construction. Workers shall be proficient in production and erection operations and shall be under the direct supervision of qualified personnel.
- Qualifications for Welding: Qualify welding processes and welding operators in accordance with ANSI/AWS D1.4. Provide certification that welders to be employed in the Work have satisfactorily passed AWS qualification tests within the previous 12 months.
- Job Mock-up Panel for Architectural Finishes: Prepare one panel using forming technique and construction methods to be used on the project for each level of finish shown on the drawings according to the following:
- Panels shall be a minimum of 4-feet by 8-feet. Incorporate edge and reveal conditions as detailed on the project drawings.
- For painted concrete finishes: Utilize full range of color as specified. Utilize reveal characterization as specified.
- For abraded or exposed colored concrete finishes: Utilize full range size and colors in aggregate. Utilize full range of color in grout. Match the degree of abrasion (e.g. sand-blast, water-blast, retarder, acid etch, etc.) specified.
- For textured or architectural liner finishes: Utilize full range of texture as specified. Sample shall consist of section showing integration of both horizontal and vertical liner joints.
- For cast-in-brick or stone finishes: Utilize full range of color sampling for brick specified. Sample shall consist of one repaired brick in field of display.
- Cast mock-up over slab joint or column joint if actual panels will be affected by these conditions.
- Maintain approved mock-up for comparison with finish work.
- Dispose of mock-up when project is completed or when directed by Architect.
1.4 PROJECT CONDITIONS
- Job Conditions: Comply with the following:
- Do not construct formwork, place steel reinforcement or concrete, or erect panels during adverse weather unless approved measures are taken to prevent damage. During period of dry winds, low humidity and other conditions causing rapid drying, protect fresh concrete with an evaporation retardant (monomolecular film) or fine fog spray of water applied immediately after screeding and bull floating. Maintain protection until final finishing and curing compounds are applied.
- For cold weather conditions, adequate equipment shall be provided for heating concrete materials and protecting concrete during freezing or near-freezing weather. Concrete materials and reinforcing steel, forms, fillers and ground with which concrete is to come in contact shall be free from frost. If shelters are used, the type of fuel used for heating shall not weaken the concrete surface. Frozen materials or materials containing ice shall not be used.
- For hot weather conditions proper attention shall be given to concrete materials, production methods, handling, placing, protection and curing to prevent excessive concrete temperatures or water evaporation that may increase shrinkage and impair required strength or serviceability of the member or structure.
- Coordinate site cast tilt-up operations with Work of other trades in order that Work may be expedited and omissions and delays avoided.
Part 2 - PRODUCTS
2.1 TILT-UP CONCRETE, GENERAL
- Comply with ACI 301, unless modified by requirements in the Contract Documents.
2.2 TILT-UP CONCRETE, GENERAL
- Forms shall contain blockouts required to provide openings detailed on Drawings. Coordinate openings with other trades.
- Panel boundary forms shall be rigidly constructed and well braced steel or wood forms, straight and with precise corners. Design to withstand stresses resulting from the casting process. Consideration should be given to exposed formed surfaces. Forming surfaces shall be smooth and clean prior to pouring of concrete.
- Forms shall be attached to the finished building slab using non-intrusive glues and/or adhesives wherever possible in lieu of nails and bolts to eliminate penetrations and blemishes. Repairs shall be approved by the Architect
- Designer/Specifier Note: Delete the above paragraph if mechanically fastening forms to exposed floor slab will not cause problems for the project with such penetrations or attachments, or if the floor slab is to receive coverings or treatments such as overlays that may be affected by the use of non-compatible glues or adhesives.
- Panels may be stacked for ease of casting, in forms as specified above.
- When panels are stack cast, maintain a continuous sound and smooth casting to match the finish of the original casting surface.
- Bondbreaker shall be compatible with curing compound and other finishes, including paint, and floor finish or be completely removed according to the manufacturer’s cleaning instructions.
- Reveal Materials: Materials used for creating reveals or relief in the exterior face of the panel shall be of adequate strength to withstand construction traffic/loads without damage.
- Concrete Materials:
- Cementitious materials shall conform to ASTM C150, C595, C1157 or C1697. Portland cement shall be Type ___. Fly Ash shall be Type ___. GGBFS shall be Grade ___.
- Fine and coarse aggregates shall consist of clean, hard strong, and durable inert material, free of injurious amounts of deleterious substances, conforming to ASTM C33 for normal weight concrete and ASTM C330 for lightweight aggregate concrete.
- Concrete shall be a design mix approved by Architect.
- Mixing water shall be free of any acid, alkali, oil or organic material that may interfere with the setting of the cement.
- Concrete shall not contain air-entrainment admixtures.
- Designer/Specifier Note: Delete the above paragraph if the concrete surface will be left natural, uncoated or abraded and exposed to a saturated condition during periods of multiple freezing and thawing cycles.
- Admixtures shall be approved by Architect.
- Concrete shall be produced and delivered in accordance with ASTM C94.
- Quality of Concrete: Ready-mixed concrete shall conform to ASTM C94. Concrete shall have a minimum compressive strength at 28 days as indicated on the project drawings and as required for panel erection, or specified, and tested according to ASTM C39.
- Sacking Materials: Portland cement and water, mixed to a uniform creamy paste.
- Dry-Pack Materials: In accordance with requirements specified in Section 03300 – Cast-in-Place Concrete.
- Steel Reinforcement:
- Reinforcing bars shall conform to ASTM A615/A615M, Grade 60, or ASTM A706/A706M. For reinforcing bars conforming to ASTM A706, which will be welded, furnish a report of the chemical analysis for each heat of the bars.
- Welded wire reinforcement shall conform to ASTM A185 or A497 based on type and location and shall be of the style shown on the project drawings. Welded wire reinforcement shall be supplied in flat sheets.
- Bar mats for concrete reinforcement shall conform to ASTM A184.
- Lifting Hardware: Lifting hardware, inserts, braces, and related embedded and attached items shall be manufactured specifically for site cast tilt-up construction.
- Randomly-Mixed Reinforcing Elements (Fibers): The use of materials mixed with the concrete for reinforcement are commonly applicable for reduction of plastic shrinkage and thermal expansion/contraction. They shall not be used as flexural reinforcement in structural panels unless approved by a licensed design professional and reviewed by the Architect. Consult the manufacturer’s literature for proper material quantities and application procedures.
- Miscellaneous Metals:
- Provide inserts, dowels, and other items to be cast in panels, including items required for erection and bracing.
- Steel that will be exposed to the exterior or damp environments in finished panels shall be plastic-tipped, hot-dipped galvanized or protected by other means to prevent corrosion or oxidation of the metal after fabrication in accordance with ASTM A123. Ensure that the plastic will not create stress concentrations within the thin sections of concrete when located near a surface from differential thermal expansion and contraction ultimately resulting in local shear failure of the concrete surface producing surface blemishes.
- Facing Aggregates:
- Material: _________________.
- Gradation: _________________.
- Color Range: _________________.
- Sand-Cement-Grout Mix: _________________.
- Sand-Cement-Grout Slump Range ______ in. to ______ in.
- Supports for Steel Reinforcement: Supports may consist of metal, all-plastic and concrete materials.
- Supports for steel reinforcement shall be designed to prevent spalling of concrete surfaces or streaking of panel face from corrosion.
- Metal supports shall be either galvanized after fabrication or with tips protected with plastic. No galvanized or plastic tip metal support shall be used on panels to receive exposed or sandblasted finish.
- All-plastic supports should be of such design as to adequately support reinforcement, provide minimal surface contact and be of such coloring as to not be distinguishable on any surfaces. Minimal surface contact is defined as having a total contact surface area not to exceed 0.10 square inches (64.5 mm²) per contact point. Refer to CRSI Manual of Standard Practice.
- Concrete supports may only be used in situations where surface contact is not visible.
2.3 CONCRETE CURING MATERIALS
- Liquid Membrane-Forming Curing Compound:
- Liquid-type membrane-forming curing compound complying with ASTM C309, Type I and I D, Class B. It is preferred that the curing compound/bondbreaker be the same product or compatible, and that only one manufacturer’s product is used.
- Concrete Curing of Casting Beds: Concrete in and around those areas to be used for casting shall be cured after finishing and as soon as the free water on the surface has disappeared and no water sheen is visible, but not so late that the liquid curing compound will be absorbed into the concrete. The cure and/or bondbreaking compound should be applied at the manufacturer’s recommended coverage to achieve minimum moisture loss.
- Curing compound must be compatible with the bond breaker and other finishes, including paint, and floor finish.
- Reusable Wet Cure Covers: Impregnated fiber mat with a white or light colored backing having low permeability with high moisture retention to maintain the proper moisture content during the concrete curing process. Comply with ASTM C171 for reflection and moisture retention.
2.4 SANDWICH INSULATION SYSTEMS
- Designer/Specifier Note: Tilt-up construction is a form of mass as referenced by the current form of ASHRAE 90.1 and the IECC. This permits the additional consideration of thermal mass to the building en-velope balance calculation when using a performance-compliance method or a lower prescriptive R-value requirement. The specifier may wish to consider altering the following paragraph to allow for both a minimum material R-value based on ASHRAE 90.1 or the applicable Energy Code and a submittal demonstrating energy balance under the provisions of ASHRAE 90.1. Mechanical system designs should consider the balance created by mass for efficient operation.
- Insulated concrete sandwich panels shall be constructed to provide a continuous layer of insulation throughout the entire panel surface. No cross section of the panel shall contain less than the specified minimum R-value below unless compliance is proven through performance-based analysis and reviewed by the Architect.
- Insulated concrete sandwich panels shall be constructed to maintain the effective acceptable material R-value of the panels with less than one percent reduction due to the wythe connections through the insulation. The reduction in thermal performance shall be calculated using the Isothermal planes method of R-value calculation as provided by ASRHAE 90.1. Install in accordance with manufacturer’s recommendations.
- Minimum R-Value: ______.
- A continuous vapor retarding membrane with a minimum thickness of ____ mil shall be installed between the outer wythe of concrete and the insulation system prior to the placement of the insulation system. All joints in the vapor retarding membrane shall be taped with a minimum 2 inch wide adhesive tape product.
- Designer/Specifier Note: Delete the above paragraph if an integral vapor barrier is not required for the project.
- Sealants and Caulking: Comply with requirements of Section 079200 – Joint Sealants.
- Liquid Dissipating Membrane-Forming Curing Compound.
- The bond breaking material shall also be a dissipating membrane forming material complying with ASTM C 309-98a, Type I and I D, Class B.
- The bond breaking compound shall be applied with adequate time to dry prior to placement of reinforcing steel.
- The bond breaking compound shall dry in 30-minutes or less at 100°F to reduce panel clean up.
- Material shall be compatible with curing material.
- The bond breaker used shall be fully removed from the slab surface or shall be compatible with any curing compound or coating specified for interior or exterior concrete panels and slab
- Comply with manufacturer’s instructions for the proper cleaning procedures and finished surface preparation for the building slab, for proper procedures for post applying a liquid floor hardener or sealant to areas where bond breaker is present, and for proper cleaning procedures for preparation of painted surface and sealer applications.
PART 3 - EXECUTION
3.1 CASTING SURFACES
- Casting Slab Preparation:
- Casting slab shall be cured. Saw cuts, cracks, joints or defects in the casting bed shall be filled so as to minimize transfer of the joint line to the panel face.
- Waste slabs, if used, shall be of sufficient thickness and strength so as not to crack with the weight of the panels.
- Contractor shall be responsible for compatibility of curing agents, sealants, and releasing agents utilized in the Work. If panels are to be stacked, the troweled surface shall be considered the casting bed and shall be treated as the same.
- Isolation pockets shall be formed in such a manner as to minimize the transfer of the pocket to the finished appearance of the panel.
- Bondbreaker shall be applied in accordance with manufacturer’s printed instructions for the applicable condition.
- Locate and install all inserts and anchorages required for the panels prior to casting of any concrete. Wet-setting of any insert is not permitted and wet-setting of any anchorage is not permitted unless approved by the Architect.
- After placing steel reinforcement for panels, check casting slab surfaces for continuity of bondbreaker. If touch-up or recoating of worn, damaged or missing areas is required, the Contractor shall remove the steel reinforcement entirely prior to re-application of the bondbreaker unless approved by the Architect.
3.2 FORMING PANELS
- Layout the panels for casting in a manner that minimizes the locations of floor joints, column isolation joints and other construction joints in the panel faces. Prevent the layout of the panels over temporarily poured casting surfaces such as pre-formed columns and pits unless deemed absolutely necessary.
- Forms shall be designed to maintain the perimeter of the panel as shown on the project drawings within 1/4-inch maximum deflection during pouring.
- Formed blockouts for openings in the panels shall be designed to limit the deflection during pouring to a maximum of 1/8 inch.
- Where reveals are specified in panels, assure that forming strips are straight and securely fastened to prevent movement or floating during placing operations and that alignment between adjacent panels is correct. Reveal tolerances shall comply with requirements specified in this Section.
3.3 PLACING CONCRETE
- Place concrete in accordance with recommendations in ACI 309 and the following:
- Concrete shall be thoroughly worked around reinforcement, around the embedded items, and into corners of the forms.
- Cold joints shall not be permitted in an individual site cast tilt-up panel.
3.4 FIELD QUALITY CONTROL TESTING
- Designer/Specifier Note: The TCA recommends both cylinder and beam tests. The embedment strength of the lifting inserts is related to the concrete compressive strength determined by the cylinders. The ability of the concrete to resist cracking during panel rotation is related to the modulus of rupture strength determined by the beams. Proceeding without both of these tests may jeopardize the success and ultimately the safety of the project.
- Field Testing:
- The Contractor shall make and store a minimum of four 6x12 cylinders or five 4x8 cylinders and four 6x6x24 beams in accordance to ASTM C31. Specimens shall be made for each class of concrete, for each 100 cu.yds. or fraction thereof, and for each day concrete is cast, or not less than once for each 5,000 sq.ft. of panel area.
- Test cylinders shall be tested in accordance with ASTM C39. A minimum of 2 from each set shall be tested at 7 days and the rest at 28 days.
- Test beams shall be tested in accordance with ASTM C78. At least two from each set shall be tested prior to panel erection. The average of the two beam results shall be considered the tested flexural strength to determine if the specified flexural strength has been met. Remaining specimens shall be kept in reserve in the event that additional testing is needed.
- Test specimens and test reports shall accurately indicate in which panel, by number and concrete delivery tag, the concrete represented by each test specimen was placed.
- Copies of test reports shall be distributed to Owner, Architect, Building Official and Contractor. Reports shall indicate location of tests, dates, technician, and other pertinent information
- Deficient Compressive Strength: In the event that concrete tests indicate a 7-day or 28-day strength below that which was specified, the Contractor with the agreement of the Architect shall have the mix adjusted so that subsequent concrete will comply with the minimum strength requirements.
- The Owner may require core specimens to be taken and tested, at the Contractor’s expense. If core tests fall below minimum requirements, as determined by the Architect, the concrete in place will be deemed to be defective.
- This concrete shall be removed and replaced or strengthened in a manner acceptable to the Owner and Architect, at the Contractor’s expense.
- Demolition or repair of other materials or systems as a result of repair or replacement of defective concrete shall be at the Contractor’s expense.
3.5 CURING AND PROTECTION
- Comply with recommendations in ACI 308 and the following:
- Protect freshly placed concrete from premature drying and excessive cold or hot temperatures, and maintain without drying at a relatively constant temperature for the period of time necessary for hydration of the cement and proper hardening of the concrete.
- Apply liquid membrane curing compound in accordance with manufacturer’s recommendations.
- Underlying panels in a stack cast arrangement shall be cured in the same manner as casting beds.
- Moist Curing in lieu of Liquid Membranes for Curing:
- Cover panels completely with burlap strips immediately after finishing. Lay as many lines of soaker hose as needed. Quickly and completely wet the entire exposed surface.
- Cover panels completely with 4-mil polyethylene, transguard or burlene to prevent evaporation. The panels shall be kept wet for seven days. Do not allow alternate wetting and drying. The polyethylene shall be turned over and down the edge of the forms and securely fastened.
- In panels or areas to be cured, weight the polyethylene, transguard or burlene with enough and type of weight to prevent normal winds for the area from blowing it off the panels. Keep panels wet until erection begins or approved by the Architect.
3.6 CASTING TOLERANCES
- Dimensions of the finished panels, prior to erection in the structure, shall conform to the casting tolerances stated below unless otherwise specified or approved by the Architect.
- Deviation from Specified Height or Width of Structural Panel:
- Up to 20 feet Plus or minus 1/4 inch
- 20 feet to 30 feet Plus or minus 3/8 inch
- Each additional 10-foot increment in excess of 30 feet Plus or minus 1/8 inch
- Maximum overall tolerance Plus or minus 5/8 inch
- Deviation from Specified Panel Thickness: Note the tolerance listed is for the average variation of panel thickness through any cross-section of the panel.
- Variation Plus or minus 3/8 inch
- Deviation in Length of Diagonals for a Rectangular Member or Opening, where Length of Diagonal is as follows. Note the tolerance listed is the measured difference in length of the two diagonals across any rectangle.
- 6 ft. or less Plus or minus 1/8 inch
- Each additional 6 ft. or part thereof Plus or minus 1/8 inch
- Not to exceed Plus or minus 1/2 inch
- Deviations from Specified Size:
- Rough opening Plus or minus 1 inch
- Finished opening Plus or minus 1/2 inch
- Rustication or architectural feature Plus or minus 1/8 inch
- Deviation from Specified Location (any direction):
- Blockout or opening Plus or minus 1 inch
- Bolts, pipes or sleeves Plus or minus 1/2 inch
- Lifting and bracing inserts per manufacturer’s specs, not to exceed Plus or minus 1 inch
- Embeds Plus or minus 1 inch
- Reglets for flashing or bricks Plus or minus 1/4 inch
- Rustication or architectural feature Plus or minus 1/8 inch
- Electrical box or accessory of another trade Plus or minus 1 inch
- Deviation from Plane:
- Embeds (Tipping & Flushness) Plus or minus 1/4 inch
- Surface of concrete between embeds Plus or minus 1/4 inch
- Depth of recess Plus or minus 1/4 inch
- Deviation from Specified Position of Reinforcement:
- Cover, in accordance with ACI 318 and in no case less than specified elsewhere Plus or minus 1/4 inch
- Individual member (location) Plus or minus 1/4 inch
- Perpendicular to plane of span Plus or minus 1/4 inch
- Parallel to plane of span Plus or minus 1 inch
- Dimensions of Thin-Brick Elements Incorporated into Tilt-up Panels:
- Thickness, variation Plus 0, minus 1/16 inch
- Maximum thickness 1 inch
- Minimum thickness 1/2 inch
- Unit dimension 8 inches or less, variation Plus 0, minus 1/16 inch
- Unit dimension greater than 8 inches, variation Plus 0, minus 3/32 inch
3.7 PANEL FINISH
- Designer/Specifier Note: It is strongly recommended that the Architect consider the finish specified as it will impact the cost of the project. It is acceptable and recommended to specify different levels of finish for the project using a key plan. Further restrictions can be made to the provisions of the finish grades of this sec-tion with the understood implication to cost.
- Finish exposed surfaces of panels as indicated on the Drawings including both the front and back of the panels as well as any exposed edges as defined below. Visible surfaces of the panels, when in place shall be free from surface defects as defined below.
- Grade A - Architectural: Projects designed for the circulation of people within a distance of 10 feet to 25 feet.
- Panel surfaces shall be free of voids, holes, pockets and other surface deformations greater than 1/8 inch.
- Surfaces of panels shall not project reinforcing patterns, floor joints or other projections or voids from the casting surface.
- Cracks are not permissible in excess of 1/32 inch.
- Surface repairs shall be performed in such a way as to prevent the projection of repair strokes through the intended finish.
- Holes shall be filled with patching material to present a smooth surface ready for painting unless the designed finish is to result in exposed aggregates whereby the patching material shall match the intended color and texture.
- Grade B - Standard: Projects designed for the circulation of people within a distance greater than 25 feet while retaining an emphasis on quality finishes and aesthetic detail.
- Panel surfaces shall be free of all voids, holes, pockets and other surface deformations greater than 1/4 inch.
- Surfaces of panels may be repaired sufficiently to prevent excessive projection of blemishes through intended finish.
- Cracks are permissible as naturally resulting from curing. Cracks are not permissible as caused by erection forces.
- Surface repairs shall improve the appearance of the panels within the descriptions above provided they do not result in additional blemishes that are visible within the distance set.
- Holes shall be filled with patching material to present a smooth surface ready for painting unless the designed finish is to result in exposed aggregates whereby the patching material shall match the intended color and texture.
- Grade C - Utility: Projects designed for remote areas with little or no public interaction and/or projects designed specifically for interior use with little or no emphasis towards the exterior design.
- Consult with the Architect and the Owner prior to initiating the project to determine the expectations for the project appearance.
- Panel surfaces showing voids, holes, pockets and other surface deformations are permissible provided they do not weaken the structural integrity of the panel or the finish of the panel/
- Cracked surfaces are permissible provided the cracks are not resulting from structural weakness or failure and provided they do not present the potential for failure of the finish over the life of the building.
- Surfaces to be painted shall be prepared to receive paint finish as specified in Section 099000 – Painting and Coating.
3.8 HANDLING AND ERECTION OF PANELS
- Engineer panels for erection stresses and selection of lifting system and hardware.
- Minimum strength of panels at time of erection shall be in accordance with the lifting design.
- It is recommended that the Contractor take extra test specimens and field cure to verify concrete strength of panels.
- Before starting erection operations, Contractor shall check relevant job site conditions insofar as they are ready for the erection of panels. Each element shall be properly marked to correspond with the designation indicated on the approved Shop Drawings.
- Use erection equipment that will prevent damage to existing construction, permanent floor slabs and panels. Damage to Work shall be repaired or replaced at the Contractor’s expense and in a manner acceptable to the Architect prior to painting or coating.
- Temporary panel bracing shall not be removed until roof diaphragm is completely welded and installed.
- Designer/Specifier Note: Typically retain subparagraph 1 following. The project Structural Engineer should verify the footing design for point loading of panel supports during construction.
- Set panels in the position assigned. Place panels evenly on prepared setting pads or proper-capacity shims. Grout space under panels for full bearing or provide additional support until grouting takes place.
- Provide sufficient number of shims to adequately distribute the load on the footing or grout as soon as practical to prevent damage of the footing.
- Panels not attached to the building frame at the time of erection shall be braced in position using a bracing system designed to resist wind and other loads that may reasonably be determined until structural connections have been made. There shall be a minimum of two braces per panel. Engineering of bracing shall be the responsibility of the Contractor. Panel bracing connection shall be maintained daily to assure tightness.
- Dry-pack grout installation and preparation for weld pockets and other panel block outs not cast in during pouring shall be performed as follows:
- Remove laitance down to sound concrete
- Surface to receive grout shall be rough and reasonably level
- Surface shall have been properly wet cured
- Do not use curing compounds
- Clean surface of oil, grease, dirt and loose particles.
- Remove free water from concrete and bolt holes immediately before grouting.
- After Panels are Erected:
- Check connecting bolts at the floor and panels daily to ensure tightness.
- Protect elements to prevent staining, warping or cracking. After panels are erected, dismantle panel erection devices and patch panels as required for a uniform appearance.
- After panels are erected, patch holes or other blemishes in casting slab that were caused by the panel casting and erection processes in a manner acceptable to the Architect.
3.9 ERECTION TOLERANCES
- Erection Tolerances: Dimensions of the finished panel in the erected position in the structure shall conform to the erection tolerances stated below unless otherwise specified or approved by the Architect.
- Deviation from Specified Dimension Between Controlling Surface or Line and Building Reference Line:
- Horizontal dimension to vertical surface Plus 1/2 inch, minus 1/4 inch.
- Vertical dimension to horizontal surface Plus 1/4 inch, minus 1/2 inch.
- From top elevation Plus or minus 1/2 inch.
- Deviation from Plumb of the Controlling Surface or Line:
- Any 10 feet of member height Plus or minus 1/4 inch
- Each additional 10 feet of height Plus or minus 1/4 inch
- Not to exceed Plus or minus 1 inch
- Deviation from Specified Relationship of Adjacent Members:
- Matching edges at horizontal and vertical joints Plus or minus 1/2 inch
- Matching faces exposed to view Plus or minus 3/8 inch
- Matching faces not exposed to view Plus or minus 3/4 inch
- Bowing between adjacent members 1/2 inch
- Alignment of brick mortar joints across joints, jog in alignment. 1/8 inch
- Alignment of brick mortar joints across joints, alignment with panel centerline Plus or minus 1/8 inch
- Deviation from Specified Joint Width:
- Vertical joint (governs over joint taper), total Plus or minus 3/8 inch.
- Horizontal joint (governs over joint taper), total Plus or minus 3/8 inch
- Visually noncritical joint Plus or minus 1/2 inch
- Joint taper over any 10 ft. length measured between the panels at the exterior face of the panels at the joint. 3/8 inch
- Joint taper over entire length measured between the panels at the exterior face of the panels at the joint Plus or minus 1/2 inch
- Variation in width of exposed brick mortar joints measured difference in joint width indicating the panel edges are not parallel Plus or minus 1/8 in
- Deviation of Architectural Features at Face of Panel:
- Brick (individual) out of plane, any one Minus 1/4 inch depth of form liner joint.
- Brick (individual) tipping, any one Minus 1/4 inch depth of form liner joint
- Brick (individual) out of square, any one Plus or minus 1/16 inch
- Brick (field), max. per panel 2 percent
3.10 SEALING OF PANEL JOINTS
- Designer/Specifier Note: The IECC 2012 instituted the requirements for continuous air barrier for climate zones above Zone 1A. For tilt-up buildings, this is easily achieved with this requirement for sealing of panel joints. The addition of the interior sealant requirement (optional) adds a double-layer protection and main-tains the cleanliness of the interior panel surface.
- Clean the panel joints of contaminants, including form release agents and concrete laitance. Dust and loose particles shall be blown out or otherwise cleaned to provide proper bond. Apply sealants in accordance with manufacturer’s recommendations.
- Install fire-resistive blanket where indicated.
- Install joint insulation where indicated to consist of a limited expansion polyurethane insulation or an approved equal as provided in accordance with Section 072000 – Insulation.
- Install back-up rod, primer, paint and sealant in accordance with Section 079200 – Sealants and Caulking.
3.11 ATTACHING PANELS TO BUILDING FRAME
- Perform welding in accordance with ANSI/AWS D1.4. Wait a minimum of 28 days from panel casting before making panel-to-panel welds.
3.12 CLEANING AND PROTECTION
- Remove trash, debris, surplus materials, tools and equipment from site on a regular basis.
- After erection, the General Contractor shall protect site-cast tilt-up concrete surfaces from damage by subsequent construction operations until Substantial Completion.
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This publication is intended for the use of professional personnel competent to evaluate the limitations of its content and who will accept responsibility for the application of its contents. It necessarily ad-dresses the specification of site cast tilt-up construction of a general nature. The professional using this publication is solely responsible for the application of its content to project documents, and for deter-mining when its content is not applicable. The tilt-up concrete association makes no representation, war-ranty, or guarantee in connection with this publication, and expressly disclaims any and all responsibility for the accuracy or application of this guideline, and for any loss or damage resulting from its use. The tilt-up concrete association is not undertaking to meet the duties of employers, manufacturers or suppli-ers to properly train, warn, and equip their employees, or others, and to comply with applicable federal, state or local regulations or laws.