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moment magnification for columns
should moment magnification be considered for sway frames, where the analysis has been made for various combinations of dead, live and earthquake loads. in such cases does it suffice to design column considering that it satisfies each and every loading combination, or do we still have to follow moment magnification factor method by separating gravity loads and lateral/earthquake loads and applying magnification factors.
second order effects must be considered either by a rational analysis method that takes into account both pδ effects and pδ effects, or by the aci delta factors.
using the aci approximate method, you have to distinguish between "sway" moments and "non-sway" moments.
i'm not sure of your exact question, but simply analyzing a frame for the required load combinations does not deal with the second order effects (i.e. moment magnification).
if your frame is very short and your axial loads are not that great, you may not have much of a second order problem. you dont have to worry if your 2nd order moments are not 5% greater than your first order moments.

2009-09-10, 02:58 PM	#1
huangyhg 超级版主注册日期: 04-03 帖子: 18592 精华: 36 现金: 249466 标准币资产: 1080358888 标准币	moment magnification for columns moment magnification for columns should moment magnification be considered for sway frames, where the analysis has been made for various combinations of dead, live and earthquake loads. in such cases does it suffice to design column considering that it satisfies each and every loading combination, or do we still have to follow moment magnification factor method by separating gravity loads and lateral/earthquake loads and applying magnification factors. second order effects must be considered either by a rational analysis method that takes into account both pδ effects and pδ effects, or by the aci delta factors. using the aci approximate method, you have to distinguish between "sway" moments and "non-sway" moments. i'm not sure of your exact question, but simply analyzing a frame for the required load combinations does not deal with the second order effects (i.e. moment magnification). if your frame is very short and your axial loads are not that great, you may not have much of a second order problem. you dont have to worry if your 2nd order moments are not 5% greater than your first order moments. __________________ 借用达朗贝尔的名言：前进吧，你会得到信心! [url="http://www.dimcax.com"]几何尺寸与公差标准[/url]