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Prestressing

Option V of  STATIK

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The prestressing module supports the analysis of prestressed beam structures like beam bridges (pre- or post-tensioned). All actions on a structure resulting from defined tendons are automatically introduced, considering the geometry and properties of the tendons and the stressing processes at their ends.


Input of Tendons

Geometry

  • Interactive graphic input. Structure lines, e.g. along the roadway axis of a bridge, act as reference lines for the tendon geometry.
  • The vertical course of a tendon is a curve through definable points for which the direction and weight of the tangents can be given. It may also contain segments with constant (minimal) radius of curvature or the layout may be polygonal for externally guided tendons.
  • The vertical course can alternatively be defined as a series of parametrized quadratic or cubic parabolas. This type of input is compatible with STATIK-3 and allows the import of tendons from STATIK-3 calculations.
  • The horizontal course results from guide lines defined in the cross sections of the members passed through. An additional horizontal excentricity can be defined by specifying a curved line, the so called plan view curve

Tendon Properties

  • Steel quality
  • bonded / unbonded
  • Friction coefficient, wobble, wedge draw-in
  • Area of strand and number of strands
  • Minimal radius of curvature

Stressing Process

The following procedures at the ends of the tendons can be specified in any order:

  • Stressing / releasing up/down to a given force
  • Releasing down to a maximum force along the tendon after anchoring
  • Considering of edge draw-ins.

Tendons may be stressed in a given construction stage and re-stressed in a later stage

Tendon Groups and Construction Stages

Tendons are always combined in groups with the following properties:

  • There is a layer for each tendon group for better viewing
  • An individual loading is generated from the actions of each tendon group
  • Each tendon group is assigned to a construction stage, which means that its tendons are not active in earlier construction stages.














Results

  • For the section force results of loadings generated from tendon groups, the fractions resulting from restraint and from the tendons can be output individually or in combination.
  • The reinforcement design is also available for prestressed beams.