how to model double ange and double channel

[mohamad reza]

hello

i want to model double angle and double channel shape for brace member in CBF frame, but i can not find suitable option for my desire in sections in seismostruct v6. how can i model this type section for brace member?

seismosoft i have a suggestion for you , it is necessary to consider the option for general section that user can calculate section proprieties such as moment of inertia ,section area,..... for every desire shape and input these data in program, such as general memeber in SAP program.

[seismosoft]

Hi,

We believe that you will find this past Forum of relevance: http://www.seismosoft.com/forum/topic.asp?TOPIC_ID=242

For what concerns your suggestion of a general section, as found in other programs, is this not what you can do already with the 'elfrm' element?

Seismosoft Support

[mohamad reza]

quote:For what concerns your suggestion of a general section, as found in other programs, is this not what you can do already with the 'elfrm' element?

thank you , yes it is similar but elfrm is elastic behavior i want to use section which i can consider nonlinear behavior such as infrmFB, i want to use truss element for brace member but how can i use elfrm? it is not possible , please guide me how can i use double angle or channel sections for brace members with considering nonlinear behavior for these

[mohamad reza]

i have other questions:

- for braces in CBFF frame which kind of materials is suitable for considering buckling behavior in compression

- which kind of steel materials can consider buckling in x bracing frame? i checked all material but no one can model buckling in compression (i checked it in "frame hysteretic curve" for brace members in compression after ran pushover analysis), i expect to it will have same behavior with bracing member in compression in fema 356.

- in modeling of X shape bracing , intersection exists at the mid point of members, in seismostruct what should we do for this situation? must we divide this? is it possible to be overlap together? or we should define structural node at intersection?

[seismosoft]

Mohamad Reza,

Your set of questions above give us the impression that you have not consulted the many past posts in this Forum on the topics of "buckling" and/or "bracing". We strongly suggest you do so.

We also suggest you to consult the following publications:
- P.C. Hsiao, D.E. Lehman, C.W. Roeder (2012) "Improved analytical model for special concentrically braced frames," Journal of Constructional Steel Research, Vol. 73, pp. 80-94
- P.C. Hsiao, D.E. Lehman, C.W. Roeder (2013), "A model to simulate special concentrically braced frames beyond brace fracture," Earthquake Engineering and Structural Dynamics, Vol. 42, pp. 183–200

Seismosoft Support