Precast Concrete
Corpus sync: neutrality remakes, note hygiene, datasheet relocation, transformer-split cross-refs
Showing changes from Rev 8
to Rev 9
in Precast Concrete.
---
title: Precast Concrete
…179 unchanged lines
- "Repair records (method and materials)"
- "Warranty documentation for installation, sealants, and coatings"
−default: [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]
+default:
+ - "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"
```
…77 unchanged lines
## 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.
−# Materials {toc}
+# Concrete {toc}
−## Concrete {toc}
+## Cement and Cementitious Materials {toc}
−### Cement and Cementitious Materials {toc}
+### The architectural face-mix cement shall be as follows:
−#### The architectural face-mix cement shall be as follows:
−
```datasheet
label: Architectural Face-Mix Cement
…7 unchanged lines
```
−#### Portland cement shall conform to ASTM C150/C150M, or blended hydraulic cement to ASTM C595/C595M.
+### Portland cement shall conform to ASTM C150/C150M, or blended hydraulic cement to ASTM C595/C595M.
−#### Silica fume conforming to ASTM C1240 may be used to increase strength and reduce permeability.
+### Silica fume conforming to ASTM C1240 may be used to increase strength and reduce permeability.
−#### For architectural face mixes, white portland cement or a controlled gray cement shall be used where required to achieve the accepted sample color.
+### For architectural face mixes, white portland cement or a controlled gray cement shall be used where required to achieve the accepted sample color.
−#### 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.
+### 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.
−#### 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. {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. {note}
−### Aggregates {toc}
+## Aggregates {toc}
−#### Aggregates shall conform to ASTM C33/C33M.
+### Aggregates shall conform to ASTM C33/C33M.
−#### 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.
+### 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.
−#### 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.
+### 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.
−### Concrete Compressive Strength {toc}
+## Concrete Compressive Strength {toc}
−#### 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. {note}
−#### The specified 28-day compressive strength shall be as follows:
+### 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. {note}
+### The specified 28-day compressive strength shall be as follows:
```datasheet
…11 unchanged lines
```
−#### 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.
+### 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.
−#### Concrete Release (Transfer) Strength {toc}
+### Concrete Release (Transfer) Strength {toc}
−##### The specified concrete strength at prestress transfer shall be as follows:
+#### The specified concrete strength at prestress transfer shall be as follows:
```datasheet
…9 unchanged lines
```
−##### 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.
+#### 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.
−##### 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. {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. {note}
−##### Release strength shall not be less than that required by the producer's design for the transfer condition.
+#### Release strength shall not be less than that required by the producer's design for the transfer condition.
−## Reinforcement {toc}
+# Reinforcement {toc}
−### Conventional Reinforcement {toc}
+## Conventional Reinforcement {toc}
−#### The conventional reinforcing bar grade shall be as follows:
+### The conventional reinforcing bar grade shall be as follows:
```datasheet
…7 unchanged lines
```
−#### 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.
+### 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.
−#### Welded wire reinforcement shall conform to ASTM A1064/A1064M.
+### Welded wire reinforcement shall conform to ASTM A1064/A1064M.
−#### The precast producer shall detail and supply the embedded reinforcement under this standard following the reinforcement detailing principles of [[sync/concrete-reinforcement]].
+### The precast producer shall detail and supply the embedded reinforcement under this standard following the reinforcement detailing principles of [[sync/concrete-reinforcement]].
−### Prestressing Strand {toc}
+## Prestressing Strand {toc}
−#### The prestressing strand grade and diameter shall be as follows:
+### The prestressing strand grade and diameter shall be as follows:
```datasheet
…19 unchanged lines
```
−#### Pretensioning strand shall be uncoated, low-relaxation, seven-wire steel strand conforming to ASTM A416/A416M.
+### Pretensioning strand shall be uncoated, low-relaxation, seven-wire steel strand conforming to ASTM A416/A416M.
−#### Low-relaxation strand shall be used in lieu of stress-relieved (normal-relaxation) strand.
+### Low-relaxation strand shall be used in lieu of stress-relieved (normal-relaxation) strand.
−#### 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. {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. {note}
−#### Strand shall be Grade 270 (270,000 psi guaranteed ultimate tensile strength) unless the producer's design requires a different grade.
+### Strand shall be Grade 270 (270,000 psi guaranteed ultimate tensile strength) unless the producer's design requires a different grade.
−#### Strand Cleanliness {toc}
+### Strand Cleanliness {toc}
−##### 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.
+#### 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.
−##### 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. {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. {note}
−##### Contaminated strand shall be cleaned or rejected.
+#### Contaminated strand shall be cleaned or rejected.
−## Connection Hardware and Embedded Plates {toc}
+# Connection Hardware and Embedded Plates {toc}
−### Embedded Steel {toc}
+## Embedded Steel {toc}
−#### 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.
+### 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.
−#### Anchorage of embedded plates into the concrete shall be by welded headed studs or deformed bar anchors developed for the design force.
+### Anchorage of embedded plates into the concrete shall be by welded headed studs or deformed bar anchors developed for the design force.
−#### Embedded hardware shall be positioned and held during casting so that its as-cast location and orientation are within the connection tolerance.
+### Embedded hardware shall be positioned and held during casting so that its as-cast location and orientation are within the connection tolerance.
−#### A weld plate cast 1 in. off position or rotated out of plane can make a field connection unweldable without remedial work. {note}
+### A weld plate cast 1 in. off position or rotated out of plane can make a field connection unweldable without remedial work. {note}
−### Corrosion Protection of Hardware {toc}
+## Corrosion Protection of Hardware {toc}
−#### The connection hardware corrosion protection and field connection method shall be as follows:
+### The connection hardware corrosion protection and field connection method shall be as follows:
```datasheet
…18 unchanged lines
```
−#### Embedded steel hardware and exposed connection steel shall be protected against corrosion as required by the service exposure.
+### Embedded steel hardware and exposed connection steel shall be protected against corrosion as required by the service exposure.
−#### For interior, dry, non-corrosive service (C0/C1), bare steel with the concrete cover providing protection is acceptable for fully embedded hardware.
+### For interior, dry, non-corrosive service (C0/C1), bare steel with the concrete cover providing protection is acceptable for fully embedded hardware.
−#### 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.
+### 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.
−#### 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.
+### 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.
−## Bearing Pads {toc}
+# Bearing Pads {toc}
−### The bearing pad type shall be as follows:
+## The bearing pad type shall be as follows:
```datasheet
…10 unchanged lines
```
−### 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.
+## 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.
−### 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.
+## 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.
−### The pad type and dimensions shall be as required by the producer's design and PCI MNL-120.
+## The pad type and dimensions shall be as required by the producer's design and PCI MNL-120.
−## Grout {toc}
+# Grout {toc}
−### The connection and bearing grout shall be as follows:
+## The connection and bearing grout shall be as follows:
```datasheet
…7 unchanged lines
```
−### Grout at bearings, leveling beds, column bases, keyways between hollow-core plank, and grouted connection sleeves shall be selected for its function.
+## Grout at bearings, leveling beds, column bases, keyways between hollow-core plank, and grouted connection sleeves shall be selected for its function.
−### Nonshrink grout for structural connections and column base plates shall conform to ASTM C1107/C1107M.
+## Nonshrink grout for structural connections and column base plates shall conform to ASTM C1107/C1107M.
−### 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. {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. {note}
−### 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.
+## 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.
# Fabrication {toc}
…411 unchanged lines
## 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.