Precast and Prestressed Concrete Manufacturing · 2020. 9. 14. · Reinforced Concrete. 3. Design 3.1. All prestressed concrete products shall be designed to support the dead load

PRECAST SPECIALTIES, LLC

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Precast and Prestressed Concrete Manufacturing

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Hollow core Slabs

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Hollow core Specifications



Specification Hollow Core Slabs

1. General

1.1. Furnish all labor and materials for the manufacturer’s delivery and installation of hollow core as specified herein and shown on drawings.

2. Applicable Publications 2.1. American Concrete Institute (ACI), latest issue 2.2. American Society for Testing and Materials (ASTM), latest issue 2.3. PCI Manual for Quality Control MNL116, last issue 2.4. PCI Manual for the Design of Hollow core Slabs, lasts issue

3. Qualifications 3.1. Manufacturer shall be a firm specializing in providing prestressed concrete products and service of

the types specified herein and on the plans; and shall have a minimum of 5 years successful experience in the fabrication of prestressed Hollow core of quality and scope required on this project.

3.2. Furnish precast prestressed Hollow core in accordance with prestressed Concrete Institute’s Manual 116 – Manual for Quality Control for Plants and Production of Precast Prestressed Concrete Products.

4. Testing 4.1. Manufacturer shall make and test concrete compression specimens representative of the work in

accordance with ASTM C-192, latest issue.

5. Submittals 5.1. Shop drawings shall be submitted for approval, showing identifying marks of each unit, holes

(other than plumbing and electrical) and anchorage details.

6. Materials 6.1. Concrete Materials

6.1.1. Portland Cement Type I or III shall conform to ASTM C-150 6.1.2. Aggregates – ASTM C-33 or C-330 6.1.3. Concrete shall be zero slump

6.2. Prestressing steel: High Tensile Three wire, 5/16”, 3/8”, or 1/2" diameter stressed relieved strand (250 or 270 KSI) tested according to ASTM-416. The wire shall be free of substances that would prevent bond to concrete.

7. Fabrication



7.1. Prestressed concrete hollow core shall be machine extruded in one single operation on long production lines in smooth rigid forms in 3’-4” nominal widths.

7.2. Openings 7.2.1. Openings requiring hanger type supplementary steel members shall be by prestressed

concrete manufacturer. 7.2.2. All other holes or openings shall be cut in field by trade requiring the openings. 7.2.3. In no case shall any hole be cut without approval of prestressed concrete manufacturer

or design engineer.

8. Tolerances 8.1. Provide units with tolerances within the limits recommended by the Prestressed Concrete

Institute’s “Manual for Quality Control for Plan and Production of Precast Prestressed Concrete Products”.

8.2. Tolerances Width Full Units +/- 1/4” Length +/- 1/2" Width Saw Cut Units +/- 1/2” Thickness +/- 1/4" Deviation from square +/- 1/4"

9. Erection 9.1. Prestressed concrete units shall be erected into final position under the supervision of the

manufacturer or erector experienced in installation of the types of units specified herein.

10. Grouting 10.1. Prestressed concrete units shall be aligned and leveled prior to grouting keyway joints in

accordance with the requirements and tolerances of PCI-MNL-116. This operation is to be performed prior to units being loaded or ends restrained.

10.2. Keyways between units shall be cleaned and filled solidly with grout. Grout that may have seeped through to surfaces in areas below shall be removed before hardening.

10.3. Fine grout shall be mixed in proportions of one part Portland cement and three parts sand with a 6” slump.

10.4. Tops of grout joints shall be adequately smooth to prevent any unevenness that might interfere with the placing of carpets or roofing. Transitions due to differential levels should be finished not steeper than 1:12. When installing tile or linoleum, slabs should have a leveling course before applying finished floor covering.

11. Topping 11.1. Topping shall be placed by General Contractor with concrete of 3000 psi minimum compressive

strength, to a minimum thickness of 2” and reinforced with a 6 x 6 – w 1.4 welded wire fabric. General Contractor shall be responsible for developing adequate bond by removing deleterious or bond inhibiting sub-substances, and wetting the surface prior to placing of topping.

12. Painting



12.1. For complete paint coverage, a minimum of one coat of heavy bodied primer (similar to block filler) and one coat of sprayed on medium to heavy texture paint is recommended with special attention to coverage of both sides of V-joints. Enamels and other flat surface paints at normal application rates do not completely bridge all surface voids and may create unsatisfactory results.



Hollow core Slab and Reinforcing

Geometry



Hollowcore Section Detail Sheets

No. HC-1 – HC-33



Wetcast Specifications



Specification Structural Prestressed Concrete

Adopted from “Guide Specifications for Precast, Prestressed Concrete Construction for Buildings”

published in the PCI Design Handbook, Precast and Prestressed Concrete Latest Edition, for compliance with standard practices in the Southeastern section of the United States.

It is recommended that specification writers select only those sections specifically applicable to the project being designed.

The Guide Specifications are in Roman Type. Notes to specification writers and designers are in italics and are not intended to be part of these specifications.

1. General 1.1. These specifications pertain to the manufacture, transportation, and erection of all pre-tensioned,

prestressed concrete products as shown on the plans. The physical characteristics of the prestressed concrete products covered by this specification and shown on the plans are as detailed in the latest catalog of Precast Specialties, LLC. Products of at least equal quality, strength, appearance, design, shape, dimensions, and otherwise meeting this specification in all respects, may be used, subject to the approval of the Architect.

1.2. Manufacture shall be by a firm specializing in providing prestressed concrete products and services of the types specified herein and on the plans. This manufacturer must show evidence of successful completion of similar and comparable work.

1.3. The prestressed concrete manufacturer shall show evidence to the Architect prior to bidding that his plant conforms to the requirements defined in Prestressed Concrete Institute Manual 116 – “Manual for Quality Control for Plans and Production of Precast Prestressed Concrete Products”.

1.4. The latest edition of the following specifications, standards, and codes shall govern with modifications as specified herein:

1.4.1. American Concrete Institute 1.4.1.1 ACI 318 – Building Code Requirements for Reinforces Concrete 1.4.1.2 ACI 301 – Specifications for Structural Concrete for Buildings

1.4.2. American Welding Society 1.4.2.1 AWS D1.0 – Code for Welding in Building Construction 1.4.2.2 AWS D12.1 – Recommended Practices for Welding Reinforcing Steel,

Metal Inserts, and Connections in Reinforced Concrete Construction

1.4.3. Prestressed Concrete Institute 1.4.3.1 MNL – 116 – Manual for Quality Control for Plants and Production of

Precast Prestressed Concrete Products



1.5. The following documents, while not a part of this specification except for sections specifically referred to herein, define recognized acceptable practices:

1.5.1. American Concrete Institute 1.5.1.1 ACI 315 – Manual of Standard Practice for Detailing Reinforced Concrete

Structures 1.5.1.2 ACI 347 – Recommended Practice for Concrete Framework

1.5.2. American Welding Society 1.5.2.1 AWS D3.0 – Standard Qualification Procedure

1.5.3. Industrial Fasteners Institute 1.5.3.1 Handbook on Fastener Standards

2. Definitions 2.1. The term pre-tensioned, prestressed concrete, referred to herein as prestressed concrete, refers

to concrete in which the prestressing tendons are tensioned prior to placing the concrete and released after the concrete has gained sufficient strength to retain the prestressing force by bond.

2.2. All other terms and symbols shall be as defined in ACI 318 – Building Code Requirements for Reinforced Concrete.

3. Design 3.1. All prestressed concrete products shall be designed to support the dead load indicated on the

plans and live loads in accordance with ACI 318 - Building Code Requirements for Reinforced Concrete.

3.2. All prestressed concrete design shall be accomplished by, or under the direct supervision of a Professional Engineer registered in the State of __________, who has had a minimum of two years responsible experience in prestressed concrete design. He shall affix his signature and seal to all design calculations and shop drawings certifying that all prestressed concrete products have been designed to meet this specification and all load criteria shown on the plans. He shall submit complete design calculations to the Architect when so requested

3.3. Permissible Design Deviations:

3.3.1. Any proposed design deviations shall be supported by complete calculations and drawings and shall have the Architect’s and/or Engineer’s approval.

3.3.2. All connection, bearing, and fitting details shown on the plans indicate the Architect’s intent. The prestressed concrete manufacturer may be permitted to modify these details if such modifications will be equally or more efficient, more consistent with latest



recommended practices of the Prestressed Concrete Institute, and no more costly. Such modifications shall be approved by the Architect.

(Note to designers: Most prestressed concrete is cast in continuous steel forms; therefore, connection devices on the formed surfaces must be contained within the members since penetration of the forms is impractical.)

3.4. All prestressed concrete products shall be designed with at least sufficient camber to properly offset deflection under full superimposed dead loads. The anticipated camber shall be computed by the prestressed concrete manufacturer.

3.4.1. Design camber in inches under full dead load should not exceed L/360 where L is the clear span in inches. Residual camber shall not vary from the design camber more than ± 1/8” per 10’ of member length with a maximum variance of 1/2”.

3.4.2. Differential camber between adjacent members in the final erected position should not exceed tolerances as defined in PCI MNL – 116 Manual for Quality Control.

(Note to designers: Computed camber figures should be relied upon only to the extent that they provide theoretical value of initial camber, which may differ from actual values when measured. Cambers less than obtained under normal design practices (L/360) may be designed for, but usually require additional prestressing steel, resulting in higher costs. Therefore, these designs should not be specified unless they are absolutely essential. Architectural details should recognize the existence of camber and camber movement in connection with closures to interior non-load bearing partitions. Closures parallel to prestressed concrete members, whether masonry, window, curtain walls, or others, must be properly detailed for appearance. In floor systems receiving poured in place topping over prestressed concrete products, the effect of camber must be recognized in topping thickness and masonry course detailing.)

4. Materials 4.1. Materials shall be as outlined in ACI 318 – Building code Requirements for Reinforced Concrete

and AISC Manual of Steel Construction and as follows:

A. Portland Cement 1. ASTM C150 – Type I or III

B. Admixtures 1. Air-Entraining Admixtures: ASTM C260 2. Water Reducing, Retarding, Accelerating Admixtures: ASTM C494

C. Aggregates 1. ASTM C33 or C330

D. Water



Potable or free from foreign materials in amounts harmful to concrete and embedded steel.

E. Reinforcing Steel 1. Bars

Deformed Billet Steel: ASTM A615 Deformed Rail Steel: ASTM A616 Deformed Axle Steel: ASTM A617 Deformed Low Alloy Steel: ASTM A706

2. Wire Cold Drawn Steel: ASTM A82

3. Wire Fabric Welded Steel: ASTM A 185 Welded Deformed Steel: ASTM A497

F. Strand 1. Uncoated 7-wire, Stress-Relieved Strand: ASTM A416 – Grade 250K or 270K

G. Anchors and Inserts 1. Materials

a. Structural Steel: ASTM A36 b. Malleable Iron c. Stainless Steel: ASTM A666

2. Finish a. Shop primer: Manufacturer’s standards b. Hot Dipped Galvanized: ASTM A153 c. Zinc-Rich Coating: MIL-P-2135, self-curing, one component, sacrificial d. Cadmium Coating

H. Grout 1. Cement grout: Portland cement, sand, and water sufficient for placement and

hydration. 2. Non-Shrink grout: Premixed, packaged ferrous and non-ferrous aggregate shrink-

resistant group.

5. Submittals 5.1. Shop Drawings

5.1.1. The prestressed concrete manufacturer shall prepare and submit to the Architect, via the General Contractor, __________ sets of shop drawings for approval and shall not proceed with manufacture prior to receiving General Contractor’s and Architect’s approval of said shop drawings.



5.1.2. Shop drawings shall show design loads, fabrication details, location of all prestressing steel, layout plans, and connection and anchorage details not indicated on the Architect’s plans, and member identification marks. The identification marks shall appear on manufactured units to facilitate correct field placement.

5.2. Certificates

5.2.1. The prestressed concrete manufacturer shall submit, when requested by the Architect, a certificate (in duplicate) stating compliance with all requirements of this Section of the specification. Submittal shall be on letterhead of company, and signed by an officer of the firm.

6. Quality Control 6.1. Testing procedures shall be in general compliance with PCI MNL-116 – Manual for Quality Control,

and as defined herein.

6.1.1. Tensioning of tendons

In all methods of tensioning, the stress induced in the tendons shall be determined by measurement of strand elongation and independently, by direct measurement of force using a pressure gauge and/or load cell. The two determinations shall check each other and the theoretical design values within a tolerance of limit 5%.

6.1.2. Detensioning of tendons

Stress transfer from anchorages to the members shall not be done until concrete strength, as indicated by test cylinders, is in accordance with the specified transfer strength. For field control of concrete, for testing cylinders, and for the design and control of concrete mixes, the prestressed concrete plant shall be equipped with adequate on-site testing equipment and staffed with personnel trained in its use. Thus, the prestressed concrete strengths may be readily and accurately determined at the time of stressing.

(Note to designers: Since the compressive strength of concrete must be determined prior to stress transfer, cylinder breaking equipment should be provided at all prestressing plants.)

6.1.3. Concrete Cylinders

6.1.3.1 Concrete shall be sampled and cylinders made in strict accordance with the following specifications: ASTM - C - 172 Sampling Fresh Concrete ASTM - C - 31 Making and Curing Concrete

6.1.3.2 At least four test cylinders per casting bed shall be made each day the bed is used.



6.2. Dimensional tolerances shall be as outlined in PCI MNL-116 – Manual for Quality Control and as defined as follows:

6.2.1. The size of all prestressed concrete members shall be as shown on the plans, with cross-section dimensional tolerance not to exceed ±1/8 inch.

6.2.2. The length dimensional tolerance shall not exceed ±1/8 inch per 10 feet of member length and shall not be greater than 3/4 inch.

6.3. Finishes to concrete surfaces shall be as outlined in PCI MNL-116 – Manual for Quality Control, with additional requirements listed below:

6.3.1. All standard shaped prestressed concrete products shall be cast in steel, fiberglass, or concrete mold. Special shaped products may be cast in accurately constructed forms with smooth interior surfaces of plastic coated wood, masonite, or similar materials.

6.3.2. Formed surfaces of prestressed concrete products shall be plant finished as indicated on the contract drawings and defined as follows:

PLANT-RUN FINISH: Some small surface holes caused by entrained air bubbles, normal form joint marks, minor chips and spalls are permitted, but major or unsightly imperfections, honeycomb, or structural defects are unacceptable.

(Note to designers: Typical locations for Plant-Run finish are: (a) storerooms, (b) shops, (c) very high roofs, (d) above suspended ceilings, and (e) where sprayed acoustical plaster is applied.)

ARCHITECTURAL GRADE A FINISH: All air pockets and holes larger than 1/4 inch shall be filled with a sand-cement paste. All form offsets or fins larger than 1/8 inch shall be ground smooth.

(Note to designers: Typical locations for Class A finish are (a) exposed unpainted, (b) painted with textured or film-forming paint, (c) spackled.)

ARCHITECTURAL GRADE AA FINISH: All Air pockets and holes, chips, spalls, form offsets, fins, and other imperfections shall be finished to a uniform texture to match adjacent areas when painted.

(Note to designers: Typical location for Class AA finish is exposed concrete painted with acrylic, latex, or water-based paints which have non-filming characteristics, especially where paint is sprayed applied. Also, preparation of surfaces to be painted should be included in the paint specification.)

6.3.3. Uniformed surfaces of prestressed concrete products shall be finished appropriately for the intended use.



(Note to designers: The finish of unformed surfaces should be very carefully defined when these surfaces are exposed and are a part of the architectural detail such as well panels or non-skid surfaces such as stadium seats.)

Standard finishes are: Roof Slabs . . . . . . . . . . . . . . . . . . . . . . . . . . medium broom Floor slabs to be topped . . . . . . . . . . . . . . heavy broom Stadium seats . . . . . . . . . . . . . . . . . . . . . . . light broom Wall panels . . . . . . . . . . . . . . . . . . . . . . . . . light broom

6.3.4. When the end of a member is to be exposed to view, the ends of the tendons shall be recessed and the recess filled with non-shrink materials in a satisfactory manner to prevent staining. Thin coats of cement mortar shall be bonded to the base member by a chemical bonding agent.

6.4. Fasteners:

6.4.1. The prestressed concrete manufacturer shall cast in structural inserts, bolts, and plates as detailed on the contract drawings.

6.4.2. Hand drilled, power drilled, and power driven inserts and studs may be placed in prestressed concrete members if not contacting or cutting the prestressing steel. Power driven inserts and studs shall be located a minimum of 6” from concrete edges to reduce spalling. If spalling does occur, the repair and finishing shall be the responsibility of trade causing same.

(Note to designers: Experience has shown that inserts and connectors should be field placed by the appropriate tradesmen whenever possible in order to provide the necessary working tolerances. Field placement, when feasible, is normally more economical. Cast-in items are not available in machine-extruded members. Consult manufacturer for recommendations.)

6.5. Deck Openings:

6.5.1. The prestressed concrete manufacturer shall precast openings 10” wide and larger, as required for skylights, vents, fans, etc., where same are specifically indicated on the contract drawings.

6.5.2. Deck openings smaller than 10” wide as required for plumbing and heating pipes, electrical conduits, outlet boxes, and similar items shall be cut in the field by each subcontractor as required for his installation. All hand chiseled holes shall be cut from the underside to prevent spalling. Power cored holes may be cut from the top. No prestressing steel or stem sections of prestressed concrete members shall be cut without prior approval of the Architect and the Prestressed Concrete Manufacturer.



(Note to designers: This specification should also be included or referenced in the Electrical section, Mechanical section, and/or any other section covering the work of trades which may find it necessary to make openings in the prestressed concrete deck. Experience indicates that most tradesmen prefer to cut their own openings because of the tolerance they so gain for their work.)

7. Transportation and Erection 7.1. Prestressed concrete members shall be lifted and supported during manufacturing operations,

stock piling, transporting, and erection only at the lifting and/or support points shown on the shop drawings.

7.2. All prestressed concrete members shall be erected into final position in the structure by the prestressed concrete manufacturer or by other competent erection personnel provided that the following requirements are fulfilled.

7.2.1. Erection shall be done with equipment, methods, and personnel acceptable to the Architect and Manufacturer.

7.2.2. Erection shall be done under the direct on-site technical guidance of the Manufacturer.

7.3. Erection shall be defined as including:

7.3.1. Placing and leveling the members in final position in the structure on bearing surfaces prepared true to the line and grade under other items of the general contract.

7.3.2. Field welding of prestressed members to each other or to supporting structural members, as shown on the plans.

7.3.3. Removal of lifting hooks, if required.

7.4. Erection normally accomplished by the Prestressed Concrete Manufacturer or other qualified erectors does not include the following:

7.4.1. Grouting, pointing, and caulking of joints.

7.4.2. Installation of closures between stems of flanged units or other members.

7.4.3. Correcting or adjusting the line and grade of bearing surfaces prepared by others.

7.4.4. Furnishing or placing field poured or dry packed concrete for topping, closures, connections, etc.

7.5. All pipes, stacks, conduits, and other such items shall be stubbed off below the bearing plane of the prestressed concrete products until after the later are set.



(Note to designers: Items No. 7.5 should be placed in Electrical, Mechanical, and Plumbing sections of project specifications also.)

8. Grouting, Pointing, and Caulking

8.1. All grouting, pointing, and caulking shall be done in a workmanlike manner by appropriate skilled tradesmen of the General Contractor, specifically as follows:

8.1.1. Grout shall be a mixture of not less than one part Portland Cement to 3 parts fine sand and the consistency shall be such that joints can be completely filled, but without seepage to other surfaces. Any grout that seeps from a joint shall be thoroughly removed before it hardens.

8.1.2. Grout for horizontal joints between slabs shall be placed from the top of the slab and finished on the underside before hardening by the following procedure, as applicable:

8.1.2.1 In areas where slabs will be used exposed or painted as the finished ceiling, rake joints 1/2 inch deep and tool smooth.

8.1.2.2 In area to receive suspended ceilings, the underside of joints need be rough broomed only.

8.1.2.3 In areas to be finished with acoustical plaster sprayed directly onto the concrete surface, rake grout 3/4 inch deep. Before acoustical plaster sprayed, the joint shall be filled with hand trowel from the underside with the same type of color of acoustical plaster to be generally used and shall be struck flush with the underside horizontal surfaces of the adjacent slabs.

8.1.3. Top of grout joints on roofs shall be troweled adequately smooth to prevent any unevenness that might interfere with the placing of, or cause damage to, insulation and roofing. Transitions due to differential levels should be finished not steeper than 1:12.

8.1.4. For sealants and caulking see Section __________.


PRECAST SPECIALTIES, LLC


Precast Specialties Representatives

Lou Bellino

Business Development – Florida

(954) 410-4038

[email protected]

Paul Davisson

VP Business Development

(561) 531-9354

[email protected]

Erika McCulloch

Business Development

(772) 834-9027

[email protected]


Precast and Prestressed Concrete Manufacturing · 2020. 9. 14. · Reinforced Concrete. 3. Design 3.1. All prestressed concrete products shall be designed to support the dead load

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