Plywood Roof Diaphragms

[Anonymous]

I am trying to model a steel pitched roof frame with timber rafters spanning one way (up the ridge) and plywood board over the top to act as a diaphragm. To save having lots of timber rafters in the model, I have omitted these from the model, but I need the plywood diaphragm in to model the wind load transfer. I used to do this by adding cross bracing in instead of diaphragms, but I would like to move on from that simplistic way of doing it if Robot allows me to.

I have a working model with panels in it to represent the diaphragm, but it is spanning 2 ways, I would like it to span one way (to represent the rafters span), I am using a shell panel. Is there a way to do this for a pitched roof?

I have attached a screenshot of the model with vertical loading only, applied as a surface load across the model. I've tried attached the robot file but it says it does match the file extension so I've attached it as a zip.

[Rafacascudo · Accepted solution]

try using "material orthotropy " shell slab type.

forum not allowing to insert a picture on the message body. But it is attached