SECTION 03366

POST TENSIONED STRUCTURAL CONCRETE

PART 1 GENERAL

SECTION INCLUDES

Cast-in-place post tensioned concrete framing members [.] [and slabs.]

Tensioned tendons and [grout filled] ducts for [bonded] [unbonded] system.

PRODUCTS FURNISHED BUT NOT INSTALLED UNDER THIS SECTION

Section [_______-__________]: Placement of anchorage [and connection] devices.

Section [______-__________]: Placement of lintels [.] [and bond beams.]

PRODUCTS INSTALLED BUT NOT FURNISHED UNDER THIS SECTION

Section [______-__________]:	Anchorage devices for [_________________.]

Section [______-__________]:	Recessed reglets for [_________________.]

RELATED SECTIONS

Section 03100 - Concrete Formwork.

Section 03200 - Concrete Reinforcement: Reinforcement from [columns] [_______] into post tensioned work.

Section 03251 - Expansion and Contraction Joints.

Section 03300 - Cast-in-Place Concrete.

Section 03346 - Concrete Floor Finishing: Finishing floor slabs.

Section [______-__________]: Traffic topping.

Section 03450 - Architectural Precast Concrete: Precast [spandrel] [________] panels.

Section [______-__________]:	Supply of metal [________] [fabrications] for casting into concrete.

Section [______-__________]: Applied surface finish.

REFERENCES

ACI 301 - Specifications for Structural Concrete for Buildings.

ACI 318 - Building Code Requirements for Reinforced Concrete.

ANSI/ACI 304 - Recommended Practice for Measuring, Mixing, Transporting, and Placing Concrete.

ANSI/ASTM A421 - Uncoated Stress-Relieved Steel Wire for Prestressed Concrete.

ANSI/ASTM A722 - Uncoated High-Strength Steel Bar for Prestressing Concrete.

ASTM A416 - Uncoated Seven-Wire Stress-Relieved Strand for Prestressed Concrete.

CRSI (Concrete Reinforcing Steel Institute) - Manual of Standard Practice.

CRSI 63 - Recommended Practice for Placing Reinforcing Bars.

CRSI 65 - Recommended Practice for Placing Bar Supports, Specifications and Nomenclature.

DESIGN REQUIREMENTS

Size components to withstand design loads as follows:

Horizontal Assembly: [___] lb/sq ft ([___] kPa) live [and dead] loads.

Vertical Assembly:	[___] lb/sq ft ([___] kPa).

Maximum Allowable Deflection: [1/180] [1/240] [1/360] [___] span.

Design members exposed to the weather to provide for movement of components without damage, failure of joint seals, undue stress on fasteners, or other detrimental effects when subject to seasonal or cyclic day/night temperature ranges.

Calculate structural properties of framing members in accordance with [ACI 301] [ACI 318] [_____] requirements.

Design deformed bar concrete reinforcement work in accordance with CRSI Manual of Standard Practice, and CRSI Documents 63 and 65.

Design system to accommodate construction tolerances, deflection of other building structural members, and clearances of intended openings.

SUBMITTALS

Submit shop drawings under provisions of Section [01300.] [01340.]

Submit shop drawings indicating layout, tendon sizes, grouping, spacing, placing sequence. [[duct] [conduit] sizes,] supports and locations, tendon supports, accessories, clearances required for jack, and pressure plate stresses.

Indicate formwork methods, materials, arrangement of joints, ties, shores, location of bracing and temporary supports, and schedule of erection and stripping.

Describe tensioning sequence, type of jack, pressure monitoring device, anchorage set, tendon elongation and tendon cut-off procedures.

Submit design data under provisions of Section [01300.] [01340.]

Submit data indicating calculations for loadings and stresses of [designed framing,] [roof and floor slabs] [and] [__________.]

Submit manufacturer's certificate under provisions of Section [01400] [01405] that tendon strength characteristics meet or exceed [specified requirements.] [__________.]

PROJECT RECORD DOCUMENTS

Submit project record documents under provisions of Section [01700.] [01720.]

Accurately record exact locations of tendons [and [ducts] [conduit]], stressing sequence, and tension loads established, elongation of tendon, [and] [__________.]

QUALIFICATIONS

Installer: Company specializing in constructing the work of this Section with minimum [three] [_____] years [documented] experience.

Design post tensioned members under direct supervision of a Professional Structural Engineer experienced in design of this work and licensed [at the place where the Project is located.] [in the State of [____________________.]]

REGULATORY REQUIREMENTS

Conform to [applicable] [_______________] code for design load and construction requirements applicable to work of this Section.

FIELD SAMPLES

Provide samples under provisions of Section [01300.] [01340.]

Provide field sample panel, [___] feet ([___] m) long by [___] feet ([___] m) wide, illustrating [__________] finish.

Locate [where directed.] [_________________________.]

Accepted sample may [not] remain as part of the Work.

PRE-INSTALLATION CONFERENCE

Convene a conference [one] [___] week prior to commencing work of this Section, under provisions of Section [01200.] [01220.]

Discuss tendon locations, sleeve locations, and cautions regarding cutting or core drilling.

ENVIRONMENTAL REQUIREMENTS

Minimum Ambient Temperature for Grouting and Grout Curing: [40] [___] degrees F ([4] [___] degrees C).

Maximum Grout Temperature (While Curing Under Pressure): [90] [___] degrees F ([32] [___] degrees C).

SEQUENCING AND SCHEDULING

Sequence work under the provisions of Section [01005.] [______.]

Schedule work under the provisions of Section [01310.] [_____.]

Coordinate work under provisions of Section [01005.] [01040.] [01041.]

Coordinate the work of framing components not post tensioned but associated with the work of this Section.

PART 2 PRODUCTS

FORMWORK

Formwork: In accordance with Section [03100.] [_____.]

REINFORCEMENT

Tendons:	ASTM A416, Grade [250] [270] stranded steel cable; ultimate tensile stress of [250] [270] ksi ([1 725] [1 860] MPa); core wire of [___] inch ([___] mm) diameter wire, six outer wire strands of [___] inch ([___] mm) diameter wire, [uncoated.] [coated with [_______________.]

****** [OR] ******

Tendons:	ANSI/ASTM A421, Type [BA for cold-end deformation.] [WA for wedge anchored ends.]; minimum tensile strength of [235] [240] [250] ksi ([1 620] [1 655] [1 725] MPa); single wire of [___] inch ([___] mm) diameter, [uncoated.] [coated with [__________].]

****** [OR] ******

Tendons:	ANSI/ASTM A722, Type [I - with plain surface] [II - with surface deformations]; ultimate tensile strength of 150 ksi ([1 035 MPa); single wire of [___] inch ([___] mm) diameter, [uncoated.] [coated with [__________].]

Tendon Anchor:	[Type compatible with tendon.] [__________.]

Reinforcing Steel: In accordance with Section [03200.] [_____.]

CONCRETE MATERIALS

Concrete Materials: In accordance with Section [03300.] [_____.]

ACCESSORIES

[Duct] [Conduit]: [Flex metal type, bright coated finish] [__________], sized to 200 percent of tendon cross sectional area [.] [, with low point drain hole.]

Sheathing: [Flexible plastic.] [Bitumen coated building paper.] [_______________.]

Grease: Noncorrosive, high viscosity.

Tie Wire: [Minimum [16] [___] gage ([1.5] [___] mm) annealed type.] [Acceptable patented system.]

Chairs, Bolsters, Bar Supports, Spacers:	Size and shape for strength and support of reinforcement during tendon location, installation, and placement of concrete.

Markers: [Colored plastic.] [_______________.]

MIXES

Proportioning:	In accordance with Section 03300.

****** [OR] ******

Proportioning:	[ACI 301, Chapter 3.] [_______________.]

Selection of Proportions for Normal Weight Concrete: [Method 1.] [Method 2.] [Method 3.]

Strength/Slump: [ACI 301, Chapter 3.] [_______________.]

Concrete for [_______________]:

[Compressive Strength (7 day): [___] psi ([___] MPa).]

[Compressive Strength (28 day): [___] psi ([___] MPa).]

Slump:	[___] inch ([___] mm).

Grout Fill for Duct:

Compressive Strength (28 day): [6000] [____] psi ([34.5] [____] MPa).

Slump:	[___] inch ([___] mm).

Grout Fill at Tendon Cut-Off:

Compressive Strength (28 day):	[___] psi ([___] MPa).

Slump:	[___] inch ([___] mm).

TESTS

Provide testing [and analysis] of stressing tendons under provisions of Section [01400.] [01410.]

Test samples in accordance with applicable ASTM standard.

PART 3 EXECUTION

INSTALLERS

[_________________________________________.]

[_________________________________________.]

[_________________________________________.]

EXAMINATION

Verify that site conditions are ready to receive work and field measurements are as [indicated on [shop drawings.] [Drawings.]] [instructed by the installer.]

Beginning of installation means installer accepts existing conditions.

FORMWORK ERECTION

Erect and support formwork in accordance with [Section [03100] [_____].] [ACI 301, Chapter 4.] [_______________.]

Provide supports and working space for tensioning jacks.

Provide permanent tendon location markers.

TENDON PLACEMENT

Locate and position tendons[.] [and [ducts] [conduit].] Protect from displacement. [Protect duct from damage; replace if damaged.]

Location Tolerance from Indicated Position: [1/8] [1/4] [1/2] inch([3] [6] [13] mm).

[Grease entire length of tendon.]

Secure jack pressure plates in position perpendicular to line of stressing force.

PLACING CONCRETE

Place concrete in accordance with [Section [03300] [_____].] [ANSI/ACI 304.] [301, Chapter 8].] [_______________.]

Verify tendons, [duct,] anchors, seats, plates, and other items to be cast into concrete are placed and secure.

CONCRETE TOLERANCES

Tolerances: In accordance with [Section [03300] [_____].] [ACI 301.] [_______________.]

Provide Class [B] [C] [A] tolerances for [floor] [roof] slabs. Pitch to drain [1/4] [___] inch per foot ([20] [___] mm/m) nominal.

TENSIONING

Begin tensioning operations after concrete has reached [___] psi ([___] MPa) compressive strength and ambient temperature is above [40] [___] degrees F ([4] [___] degrees C).

Confirm concrete strength with test cylinders prior to tensioning.

Measure prestressing force. Maintain jacking and tensioning records as work progresses.

Jack against tendon pressure plate, not against concrete.

Cut off excess tendon inside face of concrete. Apply corrosion resistive paint to cut end.

Repair duct displaced by tensioning process.	[Review repair procedure with Architect/Engineer.]

GROUTING

Execute grouting within [7] [___] days of tensioning.

[Flush ducts with water through grouting ports. Blow dry with compressed air. Ensure complete removal of flushing water.]

Pump grout through ports into ducts under pressure.

Cap venting end of grout port. Maintain grout pressure to [250] [___] psi ([1 720] [___] kPa) maximum and cap entry port.

Grout fill jacking access port.

FIELD QUALITY CONTROL

Field inspection and testing of concrete will be under

provisions of Section [03300.] [_____.]

****** [OR] ******

Field inspection and testing of concrete will be under provisions of Section [01400.] [01410.]

Take three concrete test cylinders for every [75 or less] [100 or less] [_____] cu yds ([60 or less] [75 or less] [____] cu.m) of concrete placed.

Take one additional test cylinder during cold weather concreting, cured on site under same conditions as concrete it represents.

Take one slump test for each set of test cylinders taken.

Take [two] [___] test cylinders of duct grout. Take [one] [___] slump test.

REMOVAL OF FORMS

Removal of Forms: In accordance with [Section [03100] [_____].] [ACI 301.] [_____.]

Do not remove forms [, shores,] and bracing until concrete has been tensioned to strength sufficient to carry its own weight, construction loads, and design loads.

REPAIR OF SURFACE DEFECTS

Repair of Surface Defects: In accordance with [Section [03300] [_____].] [ACI 301.] [_____.]

Request examination of concrete surfaces upon removal of forms.

Modify or replace concrete not conforming to required lines, detail, and elevations.

Repair or replace concrete not properly placed resulting in honeycombing and other defects.

END OF SECTION