Footbridge: dynamic calculations

[civilengineerNL]

Lately I've been working (for my study) on a footbridge.
I wonder if there's good open source software available to do dynamic calculations of joggers on footbridges.
I've tried Code-Aster. But didn't get it to work on my laptop under the windows environment. It seems to be a little complex for simple calculations.
It is not necessary to do advanced 3D calculations. De torsion stiffness of the bridge seems to be alright. So it's mainly bending stiffness that seems to be the problem.

The main thing I want to achieve is getting less conservative results than when I do a simple spring mass damper system check.
The jogger is not all the time giving vibrations in the center of the bridge. I want to make it more realistic.

Hope someone here can help me further on. Thanks anyhow.

 

[bridgebuster]

Get a copy of the AASHTO Guide Specifications for Pedestrian Bridges - either Standard Specifications or LRFD version. It provides an example how to treat vibrations.

 

[Guest262653]

Have you looked into OpenSees?

http://opensees.berkeley.edu/

Unfortunately, I don't think it is entirely free for commercial use...

http://opensees.berkeley.edu/OpenSees/copyright.php

 

[Guest262653]

There is also a free (limited) version of AxisVM, that may be of interest:

http://axisvm.eu/axisvm_download_free_light.html

 

[civilengineerNL]

thanks so far.

I will report later on.

 

[EQguys]

There is also a very good document by the French on how to treat vibrations in pedestrian bridges. I think this document is the state of the art in this subject. Following is the link.

http://www.infra-transports-materiaux.cerema.fr/IMG/pdf/US_0644A_Footbridges.pdf

 

[civilengineerNL]

Well first of all: thanks for sharing the information.
I've looked into the Setra. The French seem to leave the joggers out of consideration.
That's too easy for me.

But now about my progress for my report:
I now use RFEM (student license) to do non-linear dynamic calculations. I can insert sort of Heaviside functions with this.
And that seems to work fine: very user friendly and results that seem to do justice to reality.

But now I've got a question for all the dynamic experts out there.

In RFEM you have two options:
1) Time history analysis - direct integration
2) Time history analysis - Modal analysis

I am eager to find out the differences between the two. They seem to give 10% different results.
So that leaves a lot of questions.

Thanks again.