Base plate rigidity using RISA BASE

[alphaxy]

Fellow Engr's,

I had my base plate analyzed as flexible using RISA BASE Version 1.02a knowing that AISC, blodgett and other methods were using rigid analysis which results to a different value compared to flexible one. If I make use of rigid analysis in RISA base it fails, but if flexible it passed. Do I really have to force my base plate to be rigid for a conservative approach? Im having a hard time to decide on what to consider in my design since this is my first time to use this program. kindly help me out.

thanks in advance
happy new year

 

[111213]

i think the problem is the structur model.

what is the difference between rigid and flexible ?

 

[alphaxy]

111213,

I dont think model the model is incorrect. Forcing base plate to be a rigid one requires more bearing area. I just didnt know if my results were accurate considering flexible base plate since I am new to this program. For me to get an answer close to AISC, Blodgett etc. calculation I should have used rigid analysis..since my base plate fails under this condition, I looked for an alternativc considering flexible. hope you could help me on this.

 

[coug]

In fact, the rigid base assumption is BIG assumption! and very conservative. But make sure you got stiffness of the base plate right if you model it as flexible.

Frank