High axial forces in longitudinal in struts
High axial forces in longitudinal in struts
(OP)
Dear all,
For the attached long. frame , I took Temperature effect by taking max temp.=+35 and min. temp.=-35, it applied large values of axial load on the struts and the brace which made the model not safe ,consequently i changed the profiles to larger , the axial force increased and so on, reducing the profiles is not good for slenderness. I don't want to depend on the bolt hole tolerances , any suggestions ?
For the attached long. frame , I took Temperature effect by taking max temp.=+35 and min. temp.=-35, it applied large values of axial load on the struts and the brace which made the model not safe ,consequently i changed the profiles to larger , the axial force increased and so on, reducing the profiles is not good for slenderness. I don't want to depend on the bolt hole tolerances , any suggestions ?






RE: High axial forces in longitudinal in struts
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: High axial forces in longitudinal in struts
Thanks for your reply. I could do this, but the load path will be very long. What is the normal practice in such situations ?
RE: High axial forces in longitudinal in struts
BA
RE: High axial forces in longitudinal in struts
Can you exert any control over the ambient temperature at the time of installation? I've used that approach successfully in the past. You may need scheduling information of course.
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: High axial forces in longitudinal in struts
I don't have any answers beyond what KootK mentions but for craneways and such (similar type situation) you usually try to brace at the center and let the ends expand and contract with temperature changes.
Check out Eng-Tips Forum's Policies here:
FAQ731-376: Eng-Tips.com Forum Policies
RE: High axial forces in longitudinal in struts
RE: High axial forces in longitudinal in struts
RE: High axial forces in longitudinal in struts
RE: High axial forces in longitudinal in struts
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: High axial forces in longitudinal in struts
I'm showing an additional framing member since this will give you the ability to size it for just the bracing loads and not need to stiffen it up for any beam action. I'd think that laying a wide flange flat would be a good choice for this eccentric member.
RE: High axial forces in longitudinal in struts
Another suggestion: have you thought about trying slotted (horizontally) connections at the middle bay?
RE: High axial forces in longitudinal in struts
Moment frames aren't typical in the longitudinal direction of a rack, since braced frames are significantly more efficient and easier to build.
And yes, if you're in an area with significant temperature swings you should very much be designing to thermal loading if your design doesn't inherently mitigate the thermal expansion issues. If you allow it to expand out you're fine (one brace bay per structure with an intelligent bracing arrangement). If you lock it in with multiple brace bays you've got to analyze that and see if you have a problem.
RE: High axial forces in longitudinal in struts
Link
Link
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: High axial forces in longitudinal in struts