for temporary anchors.
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Corrosion protection shall be as indicated. Corrosion protection shall be
provided for the entire anchor and shall include anchorages covers and
trumpets filled with corrosion inhibiting compound or grout and
encapsulation of the free stressing length and bond length.
2.4.6.1
Anchorage Protection
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NOTE: Compound filled trumpets should only be used
for restressable anchors or anchors with permanent
load cells.
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The trumpet shall be sealed to the bearing plate and shall overlap the free
stressing length encapsulation by at least 100 mm 4 inches. The trumpet
and anchorage cover shall be completely filled with corrosion inhibiting
compound or grout. Compound filled trumpets shall have a permanent seal
between the trumpet and the free length corrosion protection.
2.4.6.2
Free Stressing Length Encapsulation
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NOTE: Encapsulation of the free stressing length is
intended to provide corrosion protection in the free
stressing length. If corrugated tubing or heat
shrinkable sleeve is used for encapsulation for
unbonded anchors, a separate bond breaker must be
used.
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Encapsulation for free stressing length shall consist of a sheath of smooth
polyethylene tubing, minimum wall thickness 1.5 mm 0.06 inch; smooth
polypropylene tubing, minimum wall thickness 1.5 mm 0.06 inch; smooth PVC
tubing, minimum wall thickness 1.0 mm 0.04 inch; steel pipe or tube with
minimum wall thickness 5.0 mm 0.20 inch or corrugated tubing conforming to
paragraph Bond Length Encapsulation. Sheath for bars and strands may be
heat shrinkable sleeve with a minimum thickness of 0.6 mm 0.024 inch. Free
stressing length encapsulation shall extend at least 100 mm 4 inches into
the trumpet, but shall not contact the bearing plate during testing and
stressing of the tendon. [Where corrugated tubing is used for sheath for
unbonded anchors, a separate bond breaker shall be provided.]
2.4.6.3
Bond Length Encapsulation
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NOTE: Encapsulation of the bond length for Class I
(Encapsulated Tendon) corrosion protection is
intended to provide corrosion protection in the bond
zone and transfer stresses from the prestressing
steel through the grout.
For Class II (Grout
Protected Tendons) corrosion protection, the grout
provides the only corrosion protection in the bond
zone, and separate encapsulation will not be
specified.
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SECTION 02490
Page 27
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