Multistrand Post-Tensioning System
Corrugated metal ducts are the most economical means to create a void for the tensile elements. These thin-walled galvanized corrugated 28ga/0.38 mm - 24ga/0.61 mm sheet metal ducts also provide a secondary corrosion protection with excellent bond behavior between tendon grout and concrete. Primary corrosion protection is provided by the alkalinity of the grout and concrete.
The tendon type number (e.g. 5904, 6807) is composed as follows:
- the first digit (5 or 6) identifies the nominal strand diameter in tenths of an inch, i.e. 0.5" or 0.6",
- The second digit is an internal code.
- the last two digits (..07) reference the number of used strands (= 7 strands).
PE/PP Round Duct
Thick-walled polyethylene / polypropylene (PPEX3) plastic ducts provide long-term secondary corrosion protection especially in aggressive environments such as waste water treatment plants, acid tanks or silos.
DYWIDAG-Systems International offers polyethylene/polypropylene (PPEX3) ducts in straight lengths up to 80 feet for all sizes. Standard shipping length is 40 feet. Longer lengths in coils are available for all sizes except 130 mm.