Cervenka Consulting Forums — Modelling prestressed Bridge Girder

Re: Modelling prestressed Bridge Girder

null@example.com (rabyaneh) — Wed, 03 Jun 2015 16:55:27 +0000

Hello Robin,

I was wondering if you had any success modeling the prestressing load "incrementally"? I am getting unexpected results from applying the load in 20 stages. I was wondering if the prestressing force is meant to be applied in a single stage, given the method that ATENA uses to convert it to "prestrain."

Thanks,

Roya

Re: Modelling prestressed Bridge Girder

null@example.com (dpryl) — Thu, 30 Jan 2014 10:11:41 +0000

A short email exchange has confirmed the typical reason of such problems, a missing support.

Re: Modelling prestressed Bridge Girder

null@example.com (robinkalfat) — Thu, 30 Jan 2014 00:54:37 +0000

By the way, I am using ATENA 3D V5

Modelling prestressed Bridge Girder

null@example.com (robinkalfat) — Thu, 30 Jan 2014 00:50:56 +0000

Hi There,

I am attempting to model a reinforced concrete prestressed bridge girder in ATENA Engineering. The girder contains about 40 bonded prestressed strands. We can assume that each strand is housed within a duct which is later grouted after tensioning, however I am not modelling the duct or the grout.

So far I have defined the bonded strands as reinforcement bars following a curved profile. I then created a prestressing load case and applied a loading of 156 kN to one end of each bonded reinforcement strand. Initially, I would like to apply the prestress incrementally as a separate load case over about 20 loading steps, however the model will not converge and I am unable to observe any stresses in the bars I have defined. I want to be able to stress the girder and observe any uplift in addition to pre-compression in the concrete. Can you please advise on how to accomplish this?

Regards

Robin