avatar  


Recently viewed tickets

Log out

Steel composite girder Bracing

Question:

Can you explain how is the bracing stiffness conversion work for steel composite girder model?

AASHTO allows 0.65 factor to be applied to the stiffness AE of the bracing/cross frame members. 
I would like to understand if the factor could be applied directly to the member. 



Answer:

Hello,

Stiffness of section can be updated in stiffness scale factor under properties tabs.




Question

Thanks for the information. But what I want to know is not the input. My question is, 

With the cross frame model in Midas using wizard, how is the "entire" cross frame convert to stiffness? AASHTO 4.6.3.3.4 is for converting cross frame with a single line of equivalent beam elements, thus, one can use the 0.65 reduction. But in Midas, cross frame is input as truss member and tie to top and bottom of girder, I am wondering on how is this apply?


Answer:

Hello,

Actually, midas wizard applies the cross frame as truss member and tie top and bottom member as stated and are designed as truss members. So, complete model for cross beam is used. Model is not using single beam method approach here, thus we need not to update the equivalent stiffness. 
But if the bracing are defined as single beam then, we can update the value of stiffness accordingly as defined earlier.
Creation date: 5/31/2021 5:16 PM (jatin2010)      Updated: 5/31/2021 5:16 PM ()
Files   
DataImage92.png
88.5 KB
DataImage95.png
180.8 KB