SAP2000 External Tendons

[engcan94]

Hi,

I am trying to model a tendon/timber hybrid truss system on SAP2000. I am having difficulties modelling an external post-tensioned tendon that is draped along the bottom of the truss chord and then diagonally up and anchored at the top of the column. It is not directly connected to the bottom chord, rather, deviator blocks are installed on the underside of the chord and the tendon runs along the blocking.

My problem is modelling the blocking such that I can model the tendon without having to connect the tendon to a joint within the truss system.

Thank you

 

[IJR]

Henry 94

SAP2000 tendon is for pre-stressed concrete. It will probably not work around any other element. Here is what I would do:

1)Model the truss and the tendon as frame members making sure the eccentricity of the tendon w.r.t the bottom chord is well modelled.
2)You will have to discretize the tendon and use rigid elements to connect the tendon to the bottom reinforcement. I think this is what you mean by deviator points.
3)Apply initial strain to the tendon. This strain is the strain corresponding to the effective prestress (i.e after losses)

Some friends suggest using ANSYS prestress capabilities. However, SAP2000 might just do the job if you work carefully and test your model with some known results.

You did not say whether your analysis is linear or inelastic. But the model is the same either way.

IJR