ASCE-SEI Committee on Cold-Formed Steel

professor ben schafer's thin-walled structures research group - johns hopkins university

 

Accommodating Building Deflections in Secondary CFS Systems

 

Mission

" develop a [brief] document dealing with how cold-formed steel framing systems should be designed to properly accommodate building deflections (vertical deflections and lateral drifts).." Email from Rob Madsen to Tom Miller, March 15, 2000

 

Commentary

The survey questions that follow will be used to (1) define the need for our contribution in this area (2) identify particular problems in this area and (3) summarize current practices in this area. 

 

As stated above the issue of concern is how to accommodate vertical and lateral deflections in a secondary cold-formed steel framing system. It is not intended to address out-of-plane deflection of the cold-formed steel system, nor get into a lengthy debate as to the correct L/whatever limit that is appropriate for CFS-Masonry, CFS-EIFS etc

 

 

Initial Survey   

 

Please enter your name

Please enter your background

(metal building designer, academic, principal of a structural design firm, etc.)  

 

What specific problems have you faced (or are you aware of) related to accommodating vertical building deflections in cold-formed steel (CFS) systems?

(general comments and specific comments - bad details, etc. are both welcome)  

 

What specific problems have you faced (or are you aware of) related to accommodating lateral building deflections in cold-formed steel (CFS) systems?  

 

 

Is there a need for better guidance on this issue, why?  

 

What is the best means of getting our collective guidance to practicioners?

(web page? CCFSS newsletter? SSMA tech note?.. ideas...)   

 

How do you currently determine the vertical deflection demands for a CFS system?  

 

How do you currently determine the lateral deflection demands for a CFS system?  

 

 

When do you consider the lateral movement of the building to be a significant design consideration? (i.e., At what demand drift do you consider the implications of the drift instead of just saying the system will "rack" and be o.k.?)   

 

Do you provide/require special details when drift demands are large?

Would you be willing to share those details with others? 

 

The answers to this survey will be compiled and used to further sharpen our focus so that we can move on to answering the second set of questions:

- What are the implications of current methods on cost, member sizes etc.?

- What is the suggested guidance from this committee on these issues?

- What are the unanswered questions and items that will require future research?

 

-Ben Schafer (schafer@jhu.edu)

 

last updated 02/16/05

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