Deflection of member 4

[dccd]

Is there anyway to check the maximum deflection of all member in the structure by viewing the l/d ratio ? How do you guys check and ensure the deflection in every member is within limit and didnt fail ?

In Staadpro , I can do it by exporting the table showing the l/d ratio and sorting it accordingly. However, in, Etabs/ SAP2000, can i do so ? When i clicked on the deflection diagram, it only showed the contour diagram of the deflection of member.... There are lots of member in the structure and by looking on the maximum deflection semms doesnt make sense at all.

 

[hotmailbox]

If the member is steel or concrete then when you run the design it will check the deflection against L/240 or L/360 or whatever you set in the design preferences. Other than that, I don't think you can get any detailed data from Etabs for post-processing regarding the member deflection. You can view one by one (each load case) by right-click on the member force diagram and check manually but that won't help. I hope ETABS API will open this in the next release.

 

[dccd]

If the member is steel or concrete then when you run the design it will check the deflection against L/240 or L/360 or whatever you set in the design preferences.

Any idea how to set the deflection limit in the program ? Can the program show the error when deflection exceed the L/240 / L/360 ??

 

[hotmailbox]

Set it in design preferences

View design info then check deflection

Similar to steel frame and concrete frame.

 

[dccd]

Mine is concrete frame. How to bring up the deflection limit and deflection ratio menu ???

 

[NewbieInSE]

dccd, that's how we check at our office.

 

[NewbieInSE]

Creep factor has to be multiplied with what is found from elastic analysis, or maybe long-term deflection has to be calculated.

 

[dccd]

Thanks.. However, the check is based on most critical member... Is it possible to set the deflection limit of l /240 and let etabs prompt is once the deflection excceded? We are unsure (in complex structure which has many members whether all members) pass deflection or not....

 

[NewbieInSE]

You have to check story wise. And you can use the colour contour to find where the max deflection occurs. It is a little tough, but still easy. In this way, it is possible to find out if any member got disconnected due to modeling error.
However I don't know of any way to set the auto L/240 limit and let the ETABS check the concrete members deflection status on its own.

As you know, for steel members, various deflection limits such L/240 for DL+LL, or L/360 for LL etc. can be set and status of members from that perspective can be found easily. But we have seen that, the deflection that ETABS gives for steel members for a load case, doesn't match with what is obtained from its moment diagram and associated deflection for the same load case. I don't know why. Does anyone know what I'm missing?