[1.3] [ ] m ()[4] [ ] feet, across the complete placement area. Place the
next lift no sooner than [4] [ ] hours from the time that the first lift is
placed.] Deposit concrete as close as possible to its final position in
the forms, and in so depositing do not permit a vertical drop greater than
1.5 mfive feet except where suitable equipment is provided to prevent
segregation and where specifically authorized. Regulate depositing of the
concrete so that it may be effectively consolidated in horizontal layers
600 mm (2.0 feet)2.0 feet or less in thickness with a minimum of lateral
movement. Deposit in each location only that amount of concrete that can
be readily and thoroughly consolidated. Thoroughly distribute and
consolidate concrete around embedded items, assuring that no air pockets
occur behind vertical items. Provide sufficient placing capacity so that
concrete can be kept plastic and free of cold joints while concrete is
being placed.
3.11.2
Preplaced-Aggregate Concrete
Install anchors and reinforcement as shown on the drawings. Place,
consolidate, finish and cure concrete in accordance with the applicable
requirements of Section 03372 PREPLACED-AGGREGATE CONCRETE.
3.11.3
Precast Concrete Units
Prepare base and install anchors as shown on the drawings. Fabricate
precast concrete units in accordance with Section 03415A
PRECAST-PRESTRESSED CONCRETE. Cure by steam at atmospheric pressure only.
3.11.3.1
Erection of Precast Units
Erect precast units in accordance with the details shown on the approved
shop drawings and erection plan for precast units, alignment plan for
precast units, approved revisions to the approved plans resulting from the
precast unit assembly test, and in accordance with Section 03415A
PRECAST-PRESTRESSED CONCRETE.
Install equipment required by other trades
as the work progresses if required by design. Do not field-cut openings in
the units unless recommended by the manufacturer and approved by the
Contracting Officer. Ensure that all bearing surfaces are level and free
from irregularities. Install precast units at right angles to bearing
surfaces, drawn up tight without forcing or distortion, and with sides
plumb. Set precast units true to alignment, level and plumb, with joints
properly spaced and aligned both vertically and horizontally. Place shims
as required as units are erected to maintain correct alignment. Install
[elastomeric expansion joint filler material], back-up material, and
neoprene bearing pads as shown on the contract drawings. Bond elastomeric
filler material and neoprene bearing pads to the precast units using
adhesive as recommended by the manufacturers. After erection, fill pickup
points, inserts, and similar items and finish with dry-pack mortar to match
adjacent areas. Erection tolerances shall be in accordance with the
requirements of PCI MNL-116.
3.11.3.2
Temporary Unit Supports
Install temporary unit supports to align precast units and support the
units during infill concrete placement. Place the temporary unit supports
well in advance of any scheduled infill concrete placement.
Secure
temporary unit supports prior to infill concrete placements and keep in
place after infill placement for at least 24 hours, unless appropriate
calculation and break histories verify that the infill concrete has reached
a strength of 500 psi sooner. Do not remove temporary unit supports in
SECTION 03931
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