STM: Defining nodal geometries based on AS3600

[N.K.]

Hi All,

Does anyone know if some of the nodal geometries shown in the document 'strut and tie model design examples for bridges' complies with the Australian code. There are some geometries woth stepped nodal faces and nodal faces that are unstressed. To me this doesn't seem like an issue but I just want to make sure I haven't missed anything before applying these rules.

In addition to this. How can one define a nodal geometry for a UDL that is applied over a wide surface. Say for example the UDL on the top of a wall (STM to take the load to discrete support points).
I have so many questions and I can't seem to find answers.

Thanks!!

 

[bugbus]

Not familiar with that document, but would be interested to see some examples.

But for the second point, I believe it's generally acceptable to approximate the UDL with a series of point loads. Alternatively, make use of fan-shaped struts, which should be able to effectively do exactly what you need.

 

[N.K.]

Hi Gusmurr,

Below is an image to one of the nodes with a stepped face on the node strut interface.

here is a link to the actual document, the image above is from page 126 if you would like to see it.

https://ctr.utexas.edu/wp-content/uploads/pubs/5_5253_01_1.pdf

Below is an image of a node with an unstressed nodal face.

It doesn't seem like there would be a problem in defining these node geometries but I just want to make sure.

As for the second part of my question, I've drawn a very simple diagrammatic example. When you simplify the UDL to a point load (as shown in the diagram) what is the dimensioning of the back face of the node, would it be the full width of the wall (or half width of the wall if I used two point loads). This might be a silly question but I want to make sure I'm doing it right. Can I assume any width and just ensure that the stress works ignoring the remaining width of wall with load on it (that is I would assume all of the load on a reduced width back face of the node).

Thanks!