几何尺寸与公差论坛------致力于产品几何量公差标准GD&T (GDT:ASME)|New GPS(ISO)研究/CAD设计/CAM加工/CMM测量  


返回   几何尺寸与公差论坛------致力于产品几何量公差标准GD&T (GDT:ASME)|New GPS(ISO)研究/CAD设计/CAM加工/CMM测量 » 三维空间:产品设计或CAX软件使用 » CAD设计 » 产品功能分析
用户名
密码
注册 帮助 会员 日历 银行 搜索 今日新帖 标记论坛为已读


回复
 
主题工具 搜索本主题 显示模式
旧 2009-09-09, 09:28 PM   #1
huangyhg
超级版主
 
huangyhg的头像
 
注册日期: 04-03
帖子: 18592
精华: 36
现金: 249466 标准币
资产: 1080358888 标准币
huangyhg 向着好的方向发展
默认 is it composite

is it composite?
the project consists of adding new ceiling hung medical equipment on the ground floor of a hospital. the building was apparently built in the 1920s, and of course there are no as-built drawings. the existing floor framing above consists of a concrete slab supported on steel beams. the concrete slab was constructed using hollow clay tile in an arch as the forms. the steel beams are at 8 feet spacing. the concrete slab is 4" thick at the midpoint between the beams and 7" thick at the beams, encasing the top flange with 2" +/- of concrete. i know this is not an encased beam, but could this be considered a composite beam? any input is welcome. thanks.
normally, we don't consider it composite without some type of mechanical anchorage which will provide for a positive means to transfer force. however, i have read, mostly as a manuscript reviewer, many articles on the various degrees of composite action developed by the very method you noted. it has been shown that a force transfer does exist and often results in the increased capacity of a concrete slab on i-girder system. the problem i find in all of this is that its largely dependent on the construction and certainly has no reliable design value without some specific testing for the system of concern. so unless you're prepared to performed some type of load testing/gauging for the system its not very useful. and because testing is expensive for what benefit may be achieved, the usual assumption of no composite connection is often used to provide a final arrangement that is without question.
incidentally, there are several articles written on how to make existing systems composite with totally tearing everything up. see the aisc journals.
qshake,
thanks for you response. i have also asked this question to aisc and they said that it is not considered composite according to latest codes. one book that i have that deals with structural renovations, suggests coring the slab above the beam and welding shear studs to the top flange to make it composite. i have a space limitation below the beam, so i this is my only practical option, unless someone has any other ideas.
would it be possible to support the medical equipment on its own frame? this could require punching through a few floors to get to the lowest level so you can install a footing under the columns. just a thought, it would be more of a sure thing then guessing on how much composite action you might get with the studs.
i should think you would still have to run some type of a load test if you go the core slab/install stud route.
just a thought!
jamie2000,
the coring and welding of studs or channels to the beam is common and is treated from a theoretical standpoint in the aisc engineering journal - not modern steel construction.
unless specifically stated in a code, i don't see why this method should require additional load testing.
additionally, this method is employed sans coring/drilling with precast deck beams often and the holes are grouted afterward.
__________________
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]
huangyhg离线中   回复时引用此帖
GDT自动化论坛(仅游客可见)
回复


主题工具 搜索本主题
搜索本主题:

高级搜索
显示模式

发帖规则
不可以发表新主题
不可以回复主题
不可以上传附件
不可以编辑您的帖子

vB 代码开启
[IMG]代码开启
HTML代码关闭

相似的主题
主题 主题发起者 论坛 回复 最后发表
incease capacity of composite beams huangyhg 产品功能分析 0 2009-09-09 07:21 PM
help with composite beam huangyhg 产品功能分析 0 2009-09-09 04:15 PM
another composite question huangyhg 产品功能分析 0 2009-09-07 12:13 PM
adding studs to existing composite beam huangyhg 产品功能分析 0 2009-09-07 10:13 AM
【转帖】composite two-single feature frame position tolerance yang686526 American standards 0 2009-04-29 07:00 PM


所有的时间均为北京时间。 现在的时间是 12:51 AM.


于2004年创办,几何尺寸与公差论坛"致力于产品几何量公差标准GD&T | GPS研究/CAD设计/CAM加工/CMM测量"。免责声明:论坛严禁发布色情反动言论及有关违反国家法律法规内容!情节严重者提供其IP,并配合相关部门进行严厉查处,若內容有涉及侵权,请立即联系我们QQ:44671734。注:此论坛须管理员验证方可发帖。
沪ICP备06057009号-2
更多