3.8.6.3
Internal Prestressing Reinforcement
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NOTE: Where both sides of the structure are
accessible, the prestressing steel may extend from
an anchor plate on one side with the stressing head
at the other side with the hole grouted after
stressing. When only one side is exposed, the
prestressing steel is grouted in place and stressed.
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Drill holes of the size and depth [shown on the drawings][recommended by
the grout manufacturer] and at the location shown. Cut recess for [anchor
plate and] stressing head in the concrete as shown. Clean the hole by
flushing with water and compressed air prior to placing grout.Dry holes as
recommended by the grout manufacturer.
Place [cement-based][polymer-modified][epoxy] grout pads [in the
recess(es)][on the face of the wall] as shown on the drawings and install
the [anchor plate,] stressing plate. [Install the threaded bar and nuts
and tighten until snug until the grout pads have set.] [Insert the
required resin cartridges into the drilled hole, taking care not to rupture
the skin. Use rapid setting cartridges in the anchor zone of the bar and
slower setting cartridges in the stressing zone. To avoid premature
rupture of the resin cartridges it may be necessary to place them in a
thin-walled tube and insert the tube in the drilled hole to the specified
depth. Withdraw the tube carefully prior to insertion of the threaded bar.
Rotate the threaded bolt through the cartridges to end of hole in
accordance with the cartridge manufacturer's recommendations in order to
rupture the skin and mix the resin. Use method, rotation time, and speed
of rotation as recommended by the manufacturer and approved by the
Contracting Officer.] No permanent installation of threaded bars will be
permitted until it is demonstrated to the satisfaction of the Contracting
Officer that the anchors can be properly installed. Stress the threaded
bar to [ ] KPa[ ] psi using equipment recommended by the bar
manufacturer. This load is the final effective (residual) load per bar
after all losses have occurred. Determine the stress load by the
measurement of the threaded bar elongation and by checking pressure of the
hydraulic jack. Correlation shall be within 5 percent of agreement. After
stressing the threaded bar, cut the bar and fill the recess with dry-pack
mortar.
3.8.6.4
External Stressing
Install anchorages as shown on the drawings. Install prestressing bars and
stress in increments in accordance with the procedure shown on the drawings
to avoid eccentric loads.
3.9
CLEANING AND RESEALING JOINTS
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NOTE: The drawings must show typical details for the
joint sealing.
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3.9.1
Preparation of Joints
Immediately before the installation of the sealant, thoroughly clean the
SECTION 03931
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