1 Scope

NOTE This specification covers the design coordination, materials, fabrication, finishing, handling, and erection of plant-fabricated precast and prestressed concrete elements for buildings. (1.1)

NOTE The work includes structural precast members — columns, beams, spandrels, double-tees, hollow-core plank, solid and insulated wall panels, and stair units — and architectural precast cladding panels with specified exposed concrete finishes. (1.2)

1.3 All work shall conform to ACI CODE-318-25, Building Code Requirements for Structural Concrete.

1.4 Work shall conform to the applicable PCI quality-control manual: PCI MNL-116 for structural precast and prestressed products, and PCI MNL-117 for architectural precast products.

1.5 Design of the precast elements and their connections shall conform to the PCI Design Handbook, MNL-120.

NOTE Precast concrete is fundamentally different from cast-in-place concrete in that the element is manufactured under controlled plant conditions, cured, demolded, and then transported and erected as a finished structural unit; this shifts the locus of quality from the field to the plant and makes release strength, handling stresses, embedded connection hardware, dimensional tolerances, and erection sequence central to the work in a way that has no parallel in cast-in-place construction. (1.6)

NOTE An element stripped from the form before it has reached release strength, or lifted at the wrong pick points, can crack before it is ever installed, and a panel cast 1/2 in. out of square multiplies into an unbuildable joint condition across a facade; the requirements of this standard protect the element from the moment of casting through final connection. (1.7)

NOTE The most important conceptual distinction in this standard is between structural precast — which carries gravity and lateral load and is governed primarily by strength, prestress, and structural-tolerance requirements, with a utility surface finish — and architectural precast, a cladding element whose appearance is a specified deliverable governed by the tighter finish, color, and tolerance requirements of PCI MNL-117. (1.8)

1.9 Elements that are simultaneously structural and architectural — an architectural spandrel, an insulated load-bearing wall panel — shall satisfy both sets of requirements.

NOTE In pretensioned (prestressed) production, high-strength seven-wire strand is tensioned against abutments before concrete is cast around it; after the concrete reaches its specified release strength the strand is detensioned and the prestressing force transfers into the member by bond, placing the member in compression, while conventionally reinforced (non-prestressed) precast is used for columns, short members, and some panels. (1.10)

1.11 The boundary of work under this standard is the precast element itself, its embedded connection hardware, its bearing pads, the grout at its bearings and connections, and the field connections that join precast to precast and precast to the supporting structure.

1.12 The supporting cast-in-place or steel structure is covered by Cast In Place ConcreteCast-in-Place ConcreteResolves to the current edition.sync/cast-in-place-concrete and the structural steel standards, and reinforcement embedded in precast elements is detailed and supplied by the precast producer under this standard consistent with Concrete ReinforcementConcrete ReinforcementResolves to the current edition.sync/concrete-reinforcement.

1.13 Sealant in the joints between panels shall be coordinated with Joint SealantsJoint SealantsResolves to the current edition.sync/joint-sealants.

2 Referenced Standards

2.1 Materials, production, finishing, testing, and erection shall comply with the latest adopted edition of the following standards and codes.

Standard	Title
ACI CODE-318-25	Building Code Requirements for Structural Concrete and Commentary
ACI 117-10 (Reapproved 2015)	Specification for Tolerances for Concrete Construction and Materials
PCI MNL-116	Manual for Quality Control for Plants and Production of Structural Precast Concrete Products
PCI MNL-117	Manual for Quality Control for Plants and Production of Architectural Precast Concrete Products
PCI MNL-120	PCI Design Handbook — Precast and Prestressed Concrete
PCI MNL-122	Architectural Precast Concrete (design and finish guidance)
PCI MNL-135	Tolerance Manual for Precast and Prestressed Concrete Construction
ASTM A416/A416M	Standard Specification for Low-Relaxation, Seven-Wire Steel Strand for Prestressed 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 A1064/A1064M	Standard Specification for Carbon-Steel Wire and Welded Wire Reinforcement for Concrete
ASTM A36/A36M	Standard Specification for Carbon Structural Steel (embedded plates and connection angles)
ASTM A572/A572M	Standard Specification for High-Strength Low-Alloy Columbium-Vanadium Structural Steel
ASTM A123/A123M	Standard Specification for Zinc (Hot-Dip Galvanized) Coatings on Iron and Steel Products
ASTM A153/A153M	Standard Specification for Zinc Coating (Hot-Dip) on Iron and Steel Hardware
ASTM A153 / ASTM F3125	Bolts and high-strength fasteners for field connections
AWS D1.1/D1.1M	Structural Welding Code — Steel (connection hardware and field welding)
AWS D1.4/D1.4M	Structural Welding Code — Reinforcing Steel
ASTM C39/C39M	Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens
ASTM C150/C150M	Standard Specification for Portland Cement
ASTM C595/C595M	Standard Specification for Blended Hydraulic Cements
ASTM C33/C33M	Standard Specification for Concrete Aggregates
ASTM C1107/C1107M	Standard Specification for Packaged Dry, Hydraulic-Cement Grout (Nonshrink)
ASTM C1240	Standard Specification for Silica Fume Used in Cementitious Mixtures
ASTM C494/C494M	Standard Specification for Chemical Admixtures for Concrete
ASTM D4014	Standard Specification for Plain and Steel-Laminated Elastomeric Bearings for Bridges (bearing pad reference)
IBC	International Building Code (locally adopted edition)

2.2 Where the contract documents, the adopted building code, a referenced standard, or the precast producer's engineering conflict, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.

3 Submittals

3.1 Action Submittals

3.1.1 The Contractor shall submit the following for the Engineer's review before fabrication begins.

3.1.2 No precast element shall be fabricated until the corresponding submittals have been reviewed and accepted.

3.1.3 Submittals shall be complete and internally coordinated; piecemeal submissions shall be rejected.

3.1.4 Shop Drawings (Erection and Production Drawings)

3.1.4.1 The precast producer shall prepare and submit erection drawings and production (shop) drawings.

3.1.4.2 Erection drawings shall show the location, mark, and orientation of every precast element, the erection sequence, all field connections, joint widths, bearing conditions, and the interface with the supporting structure.

3.1.4.3 Production drawings shall show, for each piece mark, the element geometry and dimensions, the reinforcing and prestressing layout, strand pattern and jacking force, debonding (strand sheathing) where used, concrete strengths at release and at 28 days, all embedded connection hardware with its location and orientation, lifting and handling insert locations, blockouts and openings, the finish on each face, and the chamfers and reveals.

3.1.4.4 The relationship of fabrication and placement tolerances shall be reconciled on the production drawings so that the specified connections and joints are achievable, consistent with the cumulative-tolerance principle in Concrete ReinforcementConcrete ReinforcementResolves to the current edition.sync/concrete-reinforcement.

3.1.5 Structural Design Calculations

3.1.5.1 Where the precast producer is delegated the design of the precast elements or their connections, signed and sealed design calculations shall be submitted, prepared by a registered professional engineer licensed in the jurisdiction of the project.

3.1.5.2 Calculations shall cover the in-service load condition, the prestress transfer (release) condition, and the handling conditions — stripping, storage, transportation, and erection.

NOTE The stresses during handling frequently govern the reinforcement and pick-point design of slender elements and control where lifting inserts are placed. (3.1.5.3)

3.1.6 Concrete Mix Designs

3.1.6.1 Mix designs shall be submitted for each concrete class — structural backup concrete, and each architectural face mix — showing cementitious materials, aggregates (including the facing aggregate where an exposed-aggregate finish is specified), admixtures, water-to-cementitious-materials ratio, design release strength, and design 28-day strength.

3.1.7 Samples

3.1.7.1 For architectural precast and for any structural element with an exposed finish, the producer shall submit samples that establish the accepted appearance.

3.1.7.2 Samples shall progress from initial finish samples (representing color, texture, and aggregate) to a full-size sample panel or mockup where the contract documents require one.

3.1.7.3 The accepted sample establishes the standard of appearance — color range, texture, aggregate exposure depth, and acceptable degree of color and texture variation — against which production units are judged.

3.1.8 Action Submittal Deliverables

3.1.8.1 The Contractor shall submit the following action submittals for review:

Erection drawings (piece marks, sequence, connections, joints)
Production (shop) drawings for each piece mark
Delegated-design structural calculations (sealed)
Structural concrete mix design(s)
Architectural face-mix design(s)
Connection hardware and embedded-plate product data
Prestressing strand and reinforcement certifications
Bearing pad and grout product data
Initial finish samples (color, texture, aggregate)
Full-size sample panel / mockup

Action Submittals Requiredcheckbox

☑ Erection drawings (piece marks, sequence, connections, joints)

☐ Production (shop) drawings for each piece mark

☐ Delegated-design structural calculations (sealed)

☐ Structural concrete mix design(s)

☐ Architectural face-mix design(s)

☐ Connection hardware and embedded-plate product data

☐ Prestressing strand and reinforcement certifications

☐ Bearing pad and grout product data

☐ Initial finish samples (color, texture, aggregate)

☐ Full-size sample panel / mockup

3.2 Informational Submittals

3.2.1 The Contractor shall submit the following informational submittals:

The precast plant's current PCI Plant Certification status, in the product group(s) applicable to the work
Certified mill test reports for prestressing strand (ASTM A416) and reinforcing steel (ASTM A615 or A706)
Welder qualification records (AWS D1.1 for connection steel, AWS D1.4 for reinforcing) for personnel performing plant and field welds
The producer's quality-control plan and the qualifications of the plant QC personnel

Informational Submittals Requiredcheckbox

☑ PCI Plant Certification status (applicable product groups)

☐ Certified mill test reports for strand (ASTM A416) and reinforcement (ASTM A615/A706)

☐ Welder qualification records (AWS D1.1 and AWS D1.4)

☐ Producer's quality-control plan and QC personnel qualifications

3.3 Closeout Submittals

3.3.1 The Contractor shall provide the following at project closeout:

Concrete strength test reports, including release-strength and 28-day cylinder breaks, organized by mix and casting date
Records of prestressing operations: strand jacking force, elongation measurements, and the gauge-pressure-versus-elongation reconciliation for each casting bed
As-built erection records noting any field-authorized connection or joint modifications
Repair records for any element repaired in the plant or in the field, with the method and materials used
Warranty documentation for the installation and for any specified sealants and coatings

Closeout Submittals Requiredcheckbox

☑ Concrete strength test reports (release and 28-day), by mix and casting date

☑ Prestressing operation records (jacking force, elongation, reconciliation)

☑ As-built erection records of field-authorized modifications

☑ Repair records (method and materials)

☑ Warranty documentation for installation, sealants, and coatings

4 Quality Assurance

4.1 Plant Certification

4.1.1 The required PCI Plant Certification group(s) shall be as follows:

Required PCI Plant Certification Groupcheckbox

☑ Structural products (PCI MNL-116) — beams, columns, double-tees, hollow-core, structural wall panels

☐ Architectural products (PCI MNL-117) — exposed-finish cladding panels and spandrels

☐ Bridge products (where bridge elements are within scope)

4.1.2 The precast producer shall operate a plant that holds current PCI Plant Certification in the product group(s) covering the work to be furnished — structural products certified under PCI MNL-116 and architectural products certified under PCI MNL-117 — or shall hold an equivalent recognized plant certification accepted by the Engineer.

NOTE Plant certification is the principal quality assurance for precast because the controlling production steps (form setup, strand tensioning, casting, finishing, curing, and detensioning) occur out of sight of the project site and cannot be verified after the fact by inspecting the delivered element. (4.1.3)

4.1.4 The Contractor shall furnish evidence of current certification before the first element is fabricated.

4.2 Producer's Engineer Qualifications

4.2.1 Where design of the elements or connections is delegated to the precast producer, the responsible engineer shall be a registered professional engineer licensed in the jurisdiction of the project and experienced in precast and prestressed concrete design in accordance with PCI MNL-120.

NOTE The Engineer of Record's review of delegated submittals confirms conformance with the design intent and the imposed loads; it does not transfer responsibility for the precast element design from the producer's engineer. (4.2.2)

4.3 Welder Qualifications

4.3.1 Personnel making welded connections shall be qualified under AWS D1.1 for connections of structural steel hardware and under AWS D1.4 for welds to reinforcing steel, for the processes and positions used.

4.3.2 Qualification records shall be available at the plant and at the site.

4.4 Pre-Installation Conference

4.4.1 A pre-erection conference shall be held before the first precast element is set, attended by the Contractor's superintendent, the erector, the precast producer's representative, and the Engineer.

4.4.2 The agenda shall cover the erection sequence and crane plan, connection details and required welding or grouting, bearing and shimming, joint widths and tolerances, the survey control for setting, and the inspection hold points.

4.5 Mockup Acceptance

4.5.1 Where a sample panel or mockup is required for architectural precast, no production casting of exposed units shall begin until the mockup is reviewed and accepted in writing.

4.5.2 The accepted mockup shall be retained, protected from weathering, and available at the plant and the site for comparison throughout production and erection.

5 Environmental and Service Conditions

NOTE The durability of precast concrete is governed by the ACI CODE-318-25 Chapter 19 exposure framework. (5.1)

5.2 The applicable freeze-thaw and corrosion exposure categories shall be as follows:

Freeze-Thaw Exposure (ACI 318 Category F)radio

○ F0 — not exposed to freezing and thawing in a moist condition

● F1 — exposed to freezing and thawing, moist, no deicing chemicals

○ F2 — exposed to freezing and thawing and to deicing chemicals (parking structures, exterior cladding)

Corrosion Exposure of Embedded Steel (ACI 318 Category C)radio

○ C0 — dry or protected from moisture in service

● C1 — exposed to moisture but not to external chlorides

○ C2 — exposed to moisture and an external source of chlorides (coastal, deicing salt)

5.3 The producer's mix designs shall satisfy the maximum water-to-cementitious-materials ratio and minimum strength required for the applicable exposure categories.

5.4 Architectural precast cladding is fully exposed to weather and to freeze-thaw cycling at its face, and the face mix shall be air-entrained and proportioned for that exposure even where the structural backup mix would not require it.

NOTE The C exposure category is particularly significant for prestressed precast because prestressing strand is highly sensitive to chloride-induced corrosion — a corroding strand loses cross-section and can fail by stress corrosion at far lower section loss than a passively stressed reinforcing bar. (5.5)

5.6 In C2 exposure, the cover over strand and the crack-control provisions become critical, and connection hardware shall be hot-dip galvanized or otherwise protected as specified below.

6 Concrete

6.1 Cement and Cementitious Materials

6.1.1 The architectural face-mix cement shall be as follows:

Architectural Face-Mix Cementradio

● Not applicable — structural finish only, no exposed face mix

○ Gray portland cement, single source (standard architectural)

○ White portland cement, single source (light colors and high color uniformity)

○ Blended gray/white or pigmented to match accepted sample

6.1.2 Portland cement shall conform to ASTM C150/C150M, or blended hydraulic cement to ASTM C595/C595M.

6.1.3 Silica fume conforming to ASTM C1240 may be used to increase strength and reduce permeability.

6.1.4 For architectural face mixes, white portland cement or a controlled gray cement shall be used where required to achieve the accepted sample color.

6.1.5 Cement for the face mix shall be supplied from a single source and a consistent production run for the duration of the project to control color uniformity.

NOTE Cement is the single largest contributor to base concrete color and a change in cement source is the most common cause of a visible color shift across a facade. (6.1.6)

6.2 Aggregates

6.2.1 Aggregates shall conform to ASTM C33/C33M.

6.2.2 For exposed-aggregate architectural finishes, the facing aggregate color, size, and gradation shall match the accepted sample, and it shall be supplied from a single source for the duration of the project.

6.2.3 The nominal maximum aggregate size of the structural backup mix shall be compatible with the element thickness, the reinforcement congestion, and the cover over strand.

6.3 Concrete Compressive Strength

NOTE The specified 28-day compressive strength of precast concrete is typically higher than that of comparable cast-in-place concrete, both because the structural design exploits the higher strength and because high early strength is needed to permit a daily casting cycle. (6.3.1)

6.3.2 The specified 28-day compressive strength shall be as follows:

Specified 28-Day Compressive Strength f'c — Structural Precastselect

5000 psi

6000 psi — common for prestressed members

7000 psi

8000 psi

10000 psi — high-strength members

Per drawings

6.3.3 The release strength — the strength at which prestress is transferred and the element is stripped — governs the production schedule and shall be specified separately from the 28-day strength.

6.3.4 Concrete Release (Transfer) Strength

6.3.4.1 The specified concrete strength at prestress transfer shall be as follows:

Specified Concrete Strength at Prestress Transfer (Release) f'cirange

psi

30003500400045005000

Per drawings

6.3.4.2 The concrete shall attain the specified release strength, verified by test, before prestress is transferred (strand is detensioned) or before a non-prestressed element is stripped and lifted.

NOTE Detensioning before the concrete reaches release strength overstresses the concrete at transfer and causes cracking, excessive camber, or end-zone splitting that may not be visible until later. (6.3.4.3)

6.3.4.4 Release strength shall not be less than that required by the producer's design for the transfer condition.

7 Reinforcement

7.1 Conventional Reinforcement

7.1.1 The conventional reinforcing bar grade shall be as follows:

Conventional Reinforcing Bar Gradeselect

Grade 60 (ASTM A615)

Grade 60, weldable (ASTM A706) — where welded to hardware

Grade 80 (ASTM A615) — where designed

7.1.2 Deformed reinforcing bars shall conform to ASTM A615/A615M (Grade 60 standard) or, where welding of reinforcement or enhanced ductility is required, to ASTM A706/A706M.

7.1.3 Welded wire reinforcement shall conform to ASTM A1064/A1064M.

7.1.4 The precast producer shall detail and supply the embedded reinforcement under this standard following the reinforcement detailing principles of Concrete ReinforcementConcrete ReinforcementResolves to the current edition.sync/concrete-reinforcement.

7.2 Prestressing Strand

7.2.1 The prestressing strand grade and diameter shall be as follows:

Prestressing Strand Graderadio

● Grade 270, low-relaxation, 7-wire (ASTM A416) — standard

○ Grade 250, low-relaxation, 7-wire (ASTM A416) — where designed

Strand Diameterselect

3/8 in.

7/16 in.

1/2 in. — most common in building products

0.6 in. — high-capacity members

Per drawings

7.2.2 Pretensioning strand shall be uncoated, low-relaxation, seven-wire steel strand conforming to ASTM A416/A416M.

7.2.3 Low-relaxation strand shall be used in lieu of stress-relieved (normal-relaxation) strand.

NOTE Its much lower long-term relaxation (not more than 2.5% at 1000 hours from an initial stress of 70% of guaranteed ultimate tensile strength) preserves more of the effective prestress over the life of the member and is the current production standard. (7.2.4)

7.2.5 Strand shall be Grade 270 (270,000 psi guaranteed ultimate tensile strength) unless the producer's design requires a different grade.

7.2.6 Strand Cleanliness

7.2.6.1 Strand shall be free of loose rust, oil, grease, dirt, paint, and any other bond-reducing contaminant at the time of casting, because the prestress force transfers into the concrete entirely through bond between the strand surface and the concrete.

NOTE Tightly adhered surface rust that does not produce visible pitting is acceptable and can improve bond; loose flaky rust, lubricants, and form-release overspray are not. (7.2.6.2)

7.2.6.3 Contaminated strand shall be cleaned or rejected.

8 Connection Hardware and Embedded Plates

8.1 Embedded Steel

8.1.1 Embedded connection plates, angles, weld plates, and inserts shall be fabricated from carbon structural steel conforming to ASTM A36/A36M or, where higher strength is required, high-strength low-alloy steel conforming to ASTM A572/A572M.

8.1.2 Anchorage of embedded plates into the concrete shall be by welded headed studs or deformed bar anchors developed for the design force.

8.1.3 Embedded hardware shall be positioned and held during casting so that its as-cast location and orientation are within the connection tolerance.

NOTE A weld plate cast 1 in. off position or rotated out of plane can make a field connection unweldable without remedial work. (8.1.4)

8.2 Corrosion Protection of Hardware

8.2.1 The connection hardware corrosion protection and field connection method shall be as follows:

Connection Hardware Corrosion Protectionradio

● Bare steel — interior, dry, non-corrosive service (fully embedded hardware)

○ Hot-dip galvanized after fabrication (ASTM A123 / A153) — exterior or exposed (standard for cladding)

○ Stainless steel — severe chloride or aggressive chemical exposure

Field Connection Methodcheckbox

☑ Welded — embedded plate to embedded plate, or plate to structural steel (AWS D1.1)

☐ Bolted — through embedded inserts or clip angles

☐ Grouted — keyways, sleeves, and bearing connections

☐ Doweled and grouted — column-to-foundation and column splices

8.2.2 Embedded steel hardware and exposed connection steel shall be protected against corrosion as required by the service exposure.

8.2.3 For interior, dry, non-corrosive service (C0/C1), bare steel with the concrete cover providing protection is acceptable for fully embedded hardware.

8.2.4 For exterior, moist, or chloride exposure (C2), and for all exposed connection hardware, the steel shall be hot-dip galvanized after fabrication in accordance with ASTM A123/A123M (structural shapes and plates) and ASTM A153/A153M (hardware and fasteners), or shall be stainless steel where galvanizing is insufficient.

8.2.5 Galvanized hardware shall not be welded in the field without removing the zinc coating in the weld zone and re-protecting the weld and heat-affected zone, because welding through zinc produces porous welds and toxic fume.

9 Bearing Pads

9.1 The bearing pad type shall be as follows:

Bearing Pad Typeselect

Plain elastomeric (chloroprene/neoprene) — light to moderate bearing (common for plank and tees)

Steel-laminated elastomeric — high load with rotation

Random-oriented-fiber reinforced elastomeric — higher bearing stress, less rotation

Cotton-duck reinforced (high-load, low-movement)

Thermoplastic / high-density polyethylene — high bearing, low friction

Per drawings

9.2 Precast members that bear on supports shall bear on pads that distribute the reaction, accommodate end rotation and volume-change movement, and prevent hard concrete-to-concrete or concrete-to-steel contact that would spall the bearing edges.

9.3 Bearing pad material shall be selected for the bearing stress and the movement demand: elastomeric (chloroprene/neoprene or natural rubber, plain or steel-laminated, referencing ASTM D4014), random-oriented-fiber reinforced elastomeric, cotton-duck reinforced, or thermoplastic (high-density polyethylene) pads.

9.4 The pad type and dimensions shall be as required by the producer's design and PCI MNL-120.

10 Grout

10.1 The connection and bearing grout shall be as follows:

Connection and Bearing Groutradio

○ Nonshrink, ASTM C1107 — structural connections, column bases, load-transfer bearings (standard)

○ Sand-cement keyway grout — hollow-core plank keyways (diaphragm shear)

● Both — nonshrink at connections, keyway grout at plank joints

10.2 Grout at bearings, leveling beds, column bases, keyways between hollow-core plank, and grouted connection sleeves shall be selected for its function.

10.3 Nonshrink grout for structural connections and column base plates shall conform to ASTM C1107/C1107M.

NOTE Nonshrink grout is specified at load-transferring connections because ordinary grout shrinks as it cures and loses contact with the bearing surfaces, leaving a gap that concentrates load and defeats the connection. (10.4)

10.5 Sand-cement grout or flowable grout may be used to fill plank keyways where the function is diaphragm shear transfer and load-bearing precision is not required.

11 Fabrication

11.1 Forms and Casting

11.1.1 Forms shall be mortar-tight, dimensionally accurate, and rigid enough to hold shape under the casting and (for self-stressing beds) the prestressing loads.

11.1.2 Form-release agent shall be compatible with the specified finish, and for architectural face mixes and form-liner finishes shall not stain, discolor, or interfere with the subsequent finishing operation or any applied sealer.

11.1.3 Concrete shall be placed and consolidated so that the element is fully dense and free of honeycombing, with particular care at congested end zones, around blockouts, and at the face of architectural panels where surface voids (bug holes) are an appearance defect.

11.2 Pretensioning (Prestress Transfer)

11.2.1 The prestress force verification method shall be as follows:

Prestress Force Verificationradio

● Jack gauge force and measured elongation reconciled within PCI MNL-116 tolerance (standard)

Per drawings — producer's quality-control plan

11.2.2 In pretensioned production, strand shall be tensioned against the abutments of a self-stressing bed (or against external abutments) to the jacking force shown on the production drawings before concrete is cast.

11.2.3 The applied force shall be verified by two independent means — the jack gauge pressure and the measured strand elongation — and the two shall agree within the tolerance of PCI MNL-116 (commonly ±5%).

NOTE Reconciling gauge force against elongation is the fundamental check that the design prestress is actually being delivered: a gauge-only reading can be wrong because of jack friction or a faulty gauge, and an elongation-only reading can be wrong because of strand seating and anchor slip. (11.2.4)

11.2.5 After the concrete attains the specified release strength, the strand shall be detensioned in a controlled, symmetrical sequence so that the member is not subjected to eccentric or sudden transfer that could crack it.

11.2.6 Strand Debonding and Draping

11.2.6.1 Where the design requires the prestress profile to vary along the member or to be reduced at the ends, strand shall be debonded (sheathed) at the ends or draped (harped) as shown on the production drawings.

11.2.6.2 Debonding and draping shall be executed exactly as designed because relocating or omitting a debonded length changes the transfer-condition stresses the design relied on.

11.3 Curing

NOTE Accelerated curing — typically by controlled radiant or low-pressure steam heat under a cover — is commonly used to reach release strength overnight for a daily casting cycle. (11.3.1)

11.3.2 The curing method and maximum curing temperature shall be as follows:

Curing Methodradio

● Accelerated curing (radiant or low-pressure steam) under controlled time-temperature, per PCI MNL-116 (standard for daily cycle)

○ Ambient / moist curing (where production schedule permits)

Maximum Concrete Temperature During Accelerated Curingrange

°F

140150160170

11.3.3 Precast elements shall be cured to develop the specified release strength on the production schedule and to develop the specified 28-day strength and durability.

11.3.4 Accelerated curing shall follow a controlled time-temperature regime per PCI MNL-116: a presetting (delay) period before heat is applied, a limited rate of temperature rise, a maximum holding temperature, and a controlled cooldown.

NOTE Exceeding the maximum curing temperature or heating before initial set can cause delayed ettringite formation and reduced ultimate strength, and an uncontrolled cooldown causes thermal cracking. (11.3.5)

11.4 Architectural Finishes

NOTE The finish of an architectural precast element is a specified deliverable matched to the accepted sample, produced by the selected combination of face mix, form surface or form liner, and post-strip surface treatment. (11.4.1)

11.4.2 The producer shall maintain a consistent face-mix proportion, consistent depth of treatment, and consistent timing so that the appearance does not drift across the production run.

11.4.3 Smooth (As-Cast) Form Finish

NOTE A smooth as-cast finish takes the texture of the form face directly and shows surface imperfections (bug holes, form-joint marks) readily, making it the least forgiving architectural finish. (11.4.3.1)

11.4.3.2 A smooth as-cast finish shall be used only where the form quality and the producer's bug-hole control can achieve the accepted sample.

11.4.4 Form-Liner (Textured) Finish

NOTE A form-liner finish reproduces a relief texture or pattern — board-form, fluted, brick, stone — cast into the panel face by a liner placed in the form. (11.4.4.1)

11.4.4.2 The liner pattern, depth, and joint layout shall match the accepted sample and the panel elevations and reveal layout.

11.4.5 Exposed-Aggregate Finish

NOTE An exposed-aggregate finish removes the surface cement paste to reveal the facing aggregate. (11.4.5.1)

NOTE It is produced by chemical surface retarder applied to the form face (which delays set of the surface paste so it can be washed off after stripping), by aggregate-transfer methods, or by abrasive blasting. (11.4.5.2)

11.4.5.3 The depth of exposure (light, medium, or deep reveal of the aggregate) is a specified appearance parameter and shall match the accepted sample.

11.4.6 Acid-Etched Finish

NOTE An acid-etched finish uses a controlled acid wash to dissolve a thin layer of surface paste, producing a fine, uniform, matte texture that reveals the fine aggregate and sand without exposing the coarse aggregate. (11.4.6.1)

11.4.6.2 Acid etching shall be neutralized and thoroughly rinsed; residual acid will continue to attack the surface and can cause efflorescence and staining.

11.4.7 Sandblasted (Abrasive-Blast) Finish

NOTE A sandblasted finish removes surface paste by abrasive blasting to a light, medium, or heavy texture. (11.4.7.1)

11.4.7.2 Blast depth and uniformity shall match the accepted sample, and the blast shall be carried consistently to panel edges and around reveals so that texture does not fade or intensify at the margins.

11.4.8 Architectural Finish Selection

11.4.8.1 The architectural face finish and acceptable appearance standard shall be as follows:

Architectural Face Finishselect

Not architectural — structural / utility finish only

Smooth as-cast (form finish)

Form-liner / textured pattern

Exposed aggregate — light reveal

Exposed aggregate — medium reveal

Exposed aggregate — deep reveal

Acid-etched (fine matte texture)

Sandblasted — light

Sandblasted — medium

Sandblasted — heavy

Per drawings

Acceptable Appearance Standardradio

● Match accepted full-size mockup, viewed at the specified distance and lighting

○ Match accepted initial finish sample (no full-size mockup required)

12 Tolerances

12.1 Product Tolerances

12.1.1 The product tolerance basis shall be as follows:

Product Tolerance Basisradio

● PCI MNL-135 product tolerances — structural precast (standard)

○ PCI MNL-117 architectural tolerances — exposed cladding panels (tighter)

○ Project-specific tolerances tighter than PCI — per contract documents

12.1.2 Dimensional tolerances for fabricated precast elements shall conform to PCI MNL-135 (Tolerance Manual for Precast and Prestressed Concrete Construction) for product tolerances, except where the contract documents or the architectural finish require tighter tolerances.

NOTE Product tolerances govern the dimensions of the manufactured element — length, width, thickness, squareness, position of embedded hardware and blockouts, bowing, and warping. (12.1.3)

NOTE Architectural panels carry tighter tolerances than structural elements under PCI MNL-117 because their dimensional deviations are visible in the finished facade and accumulate into joint-width variation. (12.1.4)

12.1.5 Position of Embedded Hardware

12.1.5.1 The as-cast position of connection hardware, weld plates, and inserts shall be held within the tolerance of PCI MNL-135 so that field connections fit without forcing or remedial work.

12.1.5.2 Where the connection design requires a tighter hardware position than the standard product tolerance, the production drawings shall flag the location and the tighter tolerance.

12.1.6 Bowing and Warping

12.1.6.1 Wall panels and spandrels shall be controlled for bowing (out-of-plane curvature) and warping (twist), which arise from differential prestress, differential drying, and a thermal gradient through an insulated panel.

12.1.6.2 Bowing and warping shall be within the PCI MNL-135 limits for the panel type so that adjacent panels align at their joints.

12.2 Erection Tolerances

12.2.1 The erection tolerance basis and nominal joint width shall be as follows:

Erection Tolerance Basisradio

● PCI MNL-135 erection tolerances (standard)

○ Project-specific erection tolerances per contract documents

Nominal Joint Width Between Panelsrange

in

0.50.7511.251.5

Per drawings

12.2.2 Erection (installation) tolerances are distinct from product tolerances and shall conform to PCI MNL-135 for the erected position — the location, plumb, level, and joint width of the element as set in the structure.

NOTE A piece that is within product tolerance can still be erected out of tolerance, and the joint between two pieces must absorb the sum of both pieces' product tolerances and the erection tolerance. (12.2.3)

12.2.4 Joint widths shall be designed and erected so that the specified sealant joint can accommodate the cumulative tolerance and the in-service movement, coordinated with Joint SealantsJoint SealantsResolves to the current edition.sync/joint-sealants.

13 Connections and Embedments

13.1 Reinforcement Cover

13.1.1 The concrete cover over strand and reinforcement exposed to weather shall be as follows:

Concrete Cover Over Strand / Reinforcement — Exposed to Weatherselect

1-1/2 in. — typical exposed precast

2 in. — chloride (C2) exposure or owner requirement

Per producer's design and ACI 318 for the exposure category

Per drawings

13.1.2 Concrete cover over reinforcement and prestressing strand in precast elements shall conform to ACI CODE-318-25, which permits reduced cover for plant-precast elements manufactured under controlled conditions relative to cast-in-place values, but never less than the cover required for the strand or bar size and the service exposure.

13.1.3 For prestressed members in corrosive or chloride exposure, the cover over strand is a primary corrosion-protection control and shall not be reduced below the value the producer's design requires for the C exposure category.

13.2 Welded Connections

13.2.1 Welded connections joining embedded plates to one another or to the supporting structural steel shall be made under a welding procedure qualified to AWS D1.1, by welders qualified for the process and position.

13.2.2 Welds to embedded reinforcing bar anchors shall comply with AWS D1.4.

13.2.3 The heat of field welding shall not be concentrated against the concrete in a way that spalls the surface at the embed, and the embed anchorage shall be designed to carry the connection force into the concrete without overstressing the cover.

13.3 Bolted and Doweled Connections

13.3.1 Bolted connections shall use fasteners of the specified grade, protected against corrosion to match the exposure.

13.3.2 Doweled connections — column-to-foundation, column splice, and panel-to-foundation — shall set the dowel into a preformed sleeve or cored hole and shall be filled with nonshrink grout (ASTM C1107) so that the dowel is fully encased and the connection develops the design force.

13.4 Bearing and Shimming

13.4.1 Each member shall bear on its support through the specified bearing pad, set on a leveling surface established by shims or a leveling grout bed.

13.4.2 The erector shall not reduce the bearing length below the design minimum by setting a member short on its support.

13.4.3 Shims used to set elevation shall be of a durable, non-staining material and shall be left in place or removed and drypacked as the connection detail requires.

13.4.4 Steel shims left in an exposed exterior joint shall be corrosion-protected to avoid rust staining.

14 Testing

14.1 Concrete Strength Testing

14.1.1 The release-strength cylinder curing method shall be as follows:

Release-Strength Cylinder Curingradio

● Match-cured or companion-cured with the product (standard — reflects in-form strength)

○ Standard-cured per ASTM C39 (28-day acceptance only)

14.1.2 Concrete compressive strength shall be verified by testing cylinders in accordance with ASTM C39/C39M, cured alongside the elements they represent for the release-strength determination and standard-cured for the 28-day acceptance strength.

14.1.3 Release-strength cylinders shall be cured under the same conditions as the product (match-cured or companion-cured) so that the release-strength break reflects the actual in-form concrete, not a standard-cured specimen that may be stronger or weaker than the heated element.

14.1.4 Prestress shall not be transferred and elements shall not be stripped until the release-strength cylinders confirm the specified f'ci.

14.2 Finished-Product Inspection

14.2.1 Each element shall be inspected at the plant before shipment for dimensional conformance to product tolerances, for surface defects, for the specified finish (against the accepted sample for architectural units), and for correct location of embedded hardware and lifting inserts.

14.2.2 Elements with cracks, honeycombing, exposed strand, or finish defects beyond the accepted criteria shall be repaired to an accepted standard or rejected.

14.3 Field Connection Inspection

14.3.1 Field welds shall be visually inspected and, where the contract documents or the building code require, subjected to nondestructive examination.

14.3.2 Grouted connections shall be inspected for complete fill and for the specified grout strength.

14.3.3 Bolted connections shall be inspected for the specified installation.

15 Erection and Installation

15.1 Survey and Control

15.1.1 Before erection begins, the erector shall verify the supporting structure against the erection drawings — bearing elevations, embed and anchor-bolt locations, and the dimensional control of the cast-in-place or steel frame — and shall reconcile any out-of-tolerance support condition with the Engineer before setting precast on it.

NOTE Precast erection tolerances assume the support is within its own tolerance; setting precast to a support that is itself out of tolerance compounds the error into the joints. (15.1.2)

15.2 Handling and Rigging

15.2.1 The lifting and handling method shall be as follows:

Lifting and Handlingradio

● Designed lifting inserts and rigging per producer's production drawings (standard)

○ Erector-engineered lifting plan reviewed by producer's engineer

15.2.2 Elements shall be lifted only at the designed lifting inserts and pick points shown on the production drawings, using rigging (spreader beams, lifting frames) that controls the lifting stresses.

NOTE Slender elements — long double-tees, tall thin wall panels — develop their highest tensile stresses during stripping and lifting, not in service, and lifting at the wrong points or without the designed spreader can crack an otherwise sound element. (15.2.3)

15.2.4 The erector shall follow the producer's handling instructions for orientation and support during lifting and turning.

15.3 Setting and Connection

15.3.1 Elements shall be set in the sequence shown on the erection drawings, supported and braced as required until their permanent connections are complete.

15.3.2 Members shall not be released from the crane until they are stable on their bearings or temporarily braced.

15.3.3 Tall wall panels and columns shall be braced against wind and construction loads until the permanent lateral connections and any diaphragm or grouted bases are complete.

15.3.4 Permanent connections — welds, grouted dowels, grouted keyways — shall be completed within the time the erection sequence and the bracing plan require.

15.4 Bracing

15.4.1 The temporary bracing of vertical elements shall be as follows:

Temporary Bracing of Vertical Elementsradio

● Required until permanent lateral connections complete; designed for wind and construction loads (standard)

○ Not applicable — elements stable on bearings without bracing

15.4.2 Temporary bracing shall be designed for the wind and construction loads on the unconnected element and shall remain in place until the permanent connections that replace its function are complete.

15.4.3 Removing bracing before the permanent connection is made — a frequent cause of erection-stage collapse — is prohibited.

15.5 Grouting of Joints and Bearings

15.5.1 Keyways between hollow-core plank shall be cleaned, wetted, and filled with keyway grout to develop diaphragm shear.

15.5.2 Column bases and grouted dowel sleeves shall be filled with nonshrink grout (ASTM C1107).

15.5.3 Grout shall not be placed against frozen surfaces or below the manufacturer's minimum temperature, and shall be cured to develop its strength before the connection is loaded.

15.6 Joint Sealing

15.6.1 After erection and after the panels have undergone initial volume-change movement, the joints between architectural panels shall be sealed in accordance with Joint SealantsJoint SealantsResolves to the current edition.sync/joint-sealants.

15.6.2 The joint design — width, sealant type, backer rod, and bond-breaker — shall accommodate the cumulative product and erection tolerance and the thermal and moisture movement of the panels.

NOTE Sealing the joints is coordinated with, but not part of, the precast erection scope. (15.6.3)

16 Delivery, Storage, and Handling

16.1 The storage support method shall be as follows:

Storage Supportradio

● Dunnage at designed support / pick points, elements separated and protected (standard)

○ Per producer's storage instructions for the specific element

16.2 Elements shall be marked with their piece mark and orientation and shall be transported and stored in the orientation and on the support points the producer specifies.

16.3 Storage dunnage shall be placed at or near the designed support points so that the element is not subjected to handling stresses (or sustained creep deflection) it was not designed for.

NOTE A long member stored on dunnage placed at its ends instead of its design pick points can take a permanent sag or crack. (16.4)

16.5 Architectural units shall be stored and protected so that their finished faces are not stained by runoff from other materials, by dunnage, or by rust from adjacent steel, and so that differential weathering does not mark the face before erection.

17 Repair and Patching

17.1 The architectural face repair acceptance standard shall be as follows:

Architectural Face Repair Acceptanceradio

● Color- and texture-matched to accepted sample, viewed at specified distance and lighting (standard for cladding)

○ Structural soundness only — utility finish, appearance not governed

17.2 Minor defects — chips, spalls, surface voids (bug holes) in architectural faces, and damage from handling — may be repaired to an accepted standard rather than rejecting the element, where the defect does not compromise the structural function.

17.3 Repairs to architectural faces shall match the accepted sample in color and texture when viewed at the specified distance and lighting.

NOTE A repair that is structurally sound but visibly mismatched is a finish defect on a cladding panel. (17.4)

17.5 Repair materials shall be compatible with the parent concrete and, for exposed faces, color-matched using the same face-mix constituents.

17.6 Cracks, exposed or corroded strand, and defects that affect structural capacity shall be evaluated by the producer's engineer and the Engineer of Record, and the element shall be repaired by an engineered method or rejected.

18 Warranty

18.1 The installation warranty period shall be as follows:

Installation Warranty Periodselect

1 year from substantial completion

2 years from substantial completion

18.2 The Contractor shall warrant the precast concrete work against defects in materials and workmanship — including cracking attributable to handling or erection, connection failure, grout failure, finish defects beyond the accepted criteria, and corrosion staining from inadequately protected hardware — for a period of not less than one year from substantial completion, or for the period stated in the contract documents if longer.

18.3 The warranty shall not limit the Engineer's right to require corrective work for nonconforming conditions discovered during the warranty period.

18.4 Material warranties provided by the producer, the sealant manufacturer, and any applied-coating manufacturer shall be passed through to the Owner and included in the closeout submittals.