中华钢结构论坛 China Structure Forum

标题: 膜结构应采用哪种设计方法，ASD or LRFD ? [打印本页]

作者: davidchen 时间: 2003-1-15 04:33 标题: 膜结构应采用哪种设计方法，ASD or LRFD ?

Ever since the introduction of LRFD for steel construction, the debate is on. Should we switch to LRFD (Limmited Resistanse Facored Design) for Membrane structure design? Or we stay with ASD(Allowable Stress Design)?
My suggestion is we stay with ASD. Any comment?

作者: mibao 时间: 2003-1-15 09:22 标题: 回复： ASD vs LRFD

davidchen wrote:
Ever since the introduction of LRFD for steel construction, the debate is on. Should we switch to LRFD for Membrane structure design? Or we stay with ASD? My suggestion is we stay with ASD. Any comment?

有关ASD和LRFD的讨论请参照http://okok.org/forum/viewthread ... mp;bpg=1&age=30

作者: davidchen 时间: 2003-1-18 05:32 标题: 回复： ASD vs LRFD

I should make my topic more obvious. I meant “If it is feasible to employ LRFD design method for tension structures”.

We all know for tension structure to resist external loads, first we need to introduce pre-stress into the system and then utilize deformation of the elements to our advantage. With ASD, we can find out the actual geometry changes under loads but not true with LRFD. And we will never know if our design is conservative or liberal, unless we use both methods. Do we really want to double the work here? No way!

One example is if you are designing a catenary cable anchorage of a flexible structure, you like to have the anchor bolts under direct tension to the maximum cable force; otherwise the bolts will subject to bending which is not desired. Are you going to line up with the ASD cable or LRFD cable? The answer should be obvious for this one.

This kind of problem does not happen all the time but will someday. To use LRFD for design is the trend but not necessarily the right tool for tension structure industry.

作者: skyland 时间: 2003-1-18 15:21 标题: 回复：膜结构应采用哪种设计方法，ASD or LRFD ?

ASD是允许应力设计法的缩写；LRFD是概率极限设计法的缩写。

关于这两种设计方法更详细的讨论，请参见：
Talk about USA structural steel codes [精华]
http://okok.org/forum/viewthread.php?tid=2405&h=1&bpg=1&age=30

结构设计方法的选择的确是个大问题。一方面，现在国内不论何种结构统统采用LRFD方法，忽略了结构自身的特点和现有研究水平，的确不妥；另一方面，不同的设计方法也会给设计者带来不便。因此，对这个问题希望大家能够各抒己见。

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