Frame09 – Prestress Applied to Frame Objects!!

Example Description

This model prestress applied to frame objects is verified in this example using a simply supported concrete beam with a parabolic prestressing tendon profile and different eccentricities at each end. The bending moment and deflection at the beam center are compared with independent hand-calculated results.
This model has two options for modeling the effect of the prestress. One option models the prestress as loads applied to the structure. The other models the prestress tendon as internal tendon elements. Both options are verified in this example.
In this model the beam is modeled using a single frame element that is internally meshed into two elements so that there is a node at the beam midpoint where the displacement values are to be calculated.
Three separate models are used in this analysis. Model A has the prestress modeled as loads. Models B and C treat the prestress as elements. Model B has a maximum prestress tendon discretization length of 60 inches and Model C reduces the maximum prestress tendon discretization length to 12 inches.
The effect of both wobble and curvature friction losses are included in the example as well as elastic shortening of the concrete beam. The tendon is stressed from the left end only.
Important Note: Shear deformations are included in this example.

Tested Features

•  Prestress tendon with parabolic tendon profile and different eccentricities at the two ends
•  Prestress tendon modeled using loads
•  Prestress tendon modeled as elements
•  Prestress losses