Difference between PRE and PREX in LINE of Sofiload

What’s the difference between PRE and PREX in LINE of Sofiload?


The main difference is that PREX describes an external prestressing and PRE an internal prestressing.
The two different settings therefore have different effects on the loaded beam depending on the type of the system.

  1. PRE: internal prestress (as done with the program TENDON)
    statically determined system: shortening of the beam, normal force = – P
    statically indetermined system: no strain → tendons are prestressed, cast in situ, but no normalforce within the beam, because the force is directly transferred into the supports, support reaction = + / – P

  2. PREX: external prestress
    statically determined system: Beam element under compression due to P, cable is inserted an released → beam elongation, normal force = 0
    statically indetermined system: normal force = – P, support reactions = + / – P, no deformation

In order to understand the different consequences, I have attached a small example.
Vorspannung PRE & PREX.sofistik (27.4 KB)
Vorspannung PRE & PREX.dwg (60.1 KB)

Best regards
Frederik Höller
Your SOFiSTiK Support Team

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