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fire ties anchors missing

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发表于 2009-9-9 12:01:06 | 显示全部楼层 |阅读模式
fire ties anchors missing
i generally specify fire ties at the corners of building thus that at ultimate fire collapse the corner panels will not fall outwards without warning once the roof structure fails. my local building code has requirements to this effect, even tho not specifically stated.
i have information from the manufactures for the testing and specifying of these products, and without doing to many cal's i just specify the connection details as they propose blindly.
the product i am using requires a cast-in place bolt, m20 ferrules. on local tilt panel project the cast-in place ferrules for the fire ties have been left out of the job.
i am wondering what force you would design a drilled/ expansion anchor for? and what reduction in strength due to the fire you would apply. how much would the concrete heat sink help?
i am currently thinking of trying to use a drilled anchor to fix the panel, however when i do the cal's, based on a half panel weight times a de-acceleration factor (i have assumed 3 for the moment), plus reduction factor of 0.5.
i think a better connection would be to drill through the panel and putting a m20-8.8 bolt with a large steel washer. but my building surveyor is not willing to accept the hole in the fire wall yet (i am hoping to change his mind if i can find no other alternative).
  
when in doubt, just take the next small step.

rowing engineer...not sure what your code requires, but here in the us, a safety factor of 4 is required for expansion anchors in tension.  in your case, that could cause are rather large expansion anchor.
in my experience with fire damage investigation of concrete, spalling is usually related to extinguishing the fire, not from the fire itself.  i don't know of any treatises or literature on performance of large expansion anchors under fire conditions (other than the typical suppression system hanger requirements).  simpson or hilti might have some data.
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