Design of brace in xy plane

[navids]

Hi all,

I need to add horizontal braces (in xy plane) to provide lateral stability for frames that cannot be braced. Basically I have linked top of paralel frames with x braces to create some sort of a diaphragm to stabilize the frames that i can't brace.

When i want to use SAP's design feature, SAP considers these braces as beams and try to design them as beam and gives me the error message that section needs to be class I or II so design can't be complete.

Is there a way to define the design type for an element in SAP i.e. can I define that these members need to be designed as braces?

Thanks

 

[cprr0107]

Try to model it as a tension member element only.

I have modeled one of those.
But, one problem is that these braces still carry compression though i have modeled it as a tension element only-(compression limit=0).

you may see also my post above.

cprr0107

 

[cprr0107]

and depending on your assumption for the function of your braces. offset it to the floor so it will not carry floor loadings.


cprr0107

 

[navids]

I tried tension only but it didn't change anything and SAP still tries to design it as a beam design and hence cannot complete the design.

My model only includes teh steel framing and does not have any floor loadings. I think just because the braces are horizontal, SAP assumes that they are beam.

Thanks anyways for your help.

 

[masomenos]

cprr/navids, Willis answered your concerns on modeling tension only in the previous thread. Did you follow his suggestion and run analysis cases as nonlinear? Because otherwise the tension and compression limits will be ignored.

You can select bracing then use Design menu>Steel frame design to assign design overwrites (Cb, K, etc) or select the frames which are braced and Design>Lateral bracing to assign point or uniform bracing. The lateral bracing option is fairly new. I think it was introduced in V14.1 or V14.2