Bonded Strand Post-Tensioning System
DYWIDAG-Systems International has developed three different methods to insert strands into ducts. The selection of the insertion method depends on the boundary conditions of the structure and the job site.
Method 1: Pushing
To push strands into the duct on the job site is very economical and can be done either before or after casting the concrete. The pushing equipment can be installed remotely and connected flexibly to the insertion point. DSI strand pushers provide relatively high speed of up to 8 m/s and require minimal operating personnel of only two men. These advantages make this method the preferred standard for strand installation.
Method 2: Pulling
To install strands while pulling them into the duct can be very efficient in special structures, for example where the loop anchorage is used. In normal cases, the whole bundle of strands is pulled through winching with a steel cable.