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A23.4-09
©
Canadian Standards Association
November 2009
27.2
Surface sealers and joint sealants specified by the owner shall be applied in accordance with the
manufacturer’s instructions.
Notes:
(1)
PCI MNL-122 provides some information on the merits of sealers and the types of joint sealants.
(2)
The application of some sealers and joint sealants should be delayed so that it follows the completion of installation
and joints.
(3)
Before actual application on the finished product, sealers and joint sealants should be tested on reasonably sized
samples of varying ages and their performance verified over a suitable period based on experience under similar
exposure conditions.
28 Prestressing
28.1 Post-tensioning
Post-tensioning shall comply with Clause 6.8 of CSA A23.1.
28.2 Pretensioning
28.2.1 General
The prestress force to be applied to the tendon shall be calculated in accordance with Clause 18 of
CAN/CSA-A23.3, taking into consideration the specified effective prestress force and prestress losses. The
prestress force shall be shown on the shop drawings.
28.2.2 Facilities
28.2.2.1
Prestressing beds shall comply with the following requirements:
(a) Anchorages, abutments, stress-resisting forms, and deflecting equipment shall be designed by
experienced engineers and reviewed by the manufacturer’s engineer.
(b) The design shall be based upon a stated factor of safety in accordance with sound engineering
principles, taking into account the maximum forces on the bed. Such forces shall be analyzed as to
magnitude, position, and frequency of occurrence.
(c) Foundations shall be sufficiently firm to prevent undesirable movements.
Note:
For examples of pretensioning application, see the
CPCI Design Manual
.
28.2.2.2
Information on the capacity of each bed and stress-resisting form, in terms of allowable prestress force and
its corresponding height of application above the bed or base, shall be kept on record and made available
when requested.
28.2.3 Equipment
28.2.3.1
The tensioning force shall be applied by equipment suitable for single-tendon tensioning.
28.2.3.2
Hydraulic gauges, dynamometers, tension meters, load cells, pressure transducers, digital indicators, or
other suitable force-measurement systems shall be used for controlling and measuring the prestress force
and shall comply with the following requirements:
(a) They shall have an accuracy of reading within ±2%.
Licensed for/Autorisé à Jed Friesen Sold by/vendu par CSA on/le June/18/2015.
~Single user license only. Storage, distribution or use on network prohibited. Permis d'utilisateur simple seulement.
Le stockage, la distribution ou l'utilisation sur le réseau est interdit.