I have an interesting situation where I have 2 steel beams with steel pipe end plates to support some large loads. Please see the attached sketch.
I am concerned about the transfer of moment and shear through the pipe to the support and how I can strengthen it externally.
Any comments or...
Thanks Ron and Hokie66 - Interesting stuff.
I have felt the resonant quality you mentioned before whilst taxiing around and also noticed it by the deflection (or 'bouncing') of the wings. There would be a substantial saving in designing the central areas to 75% of loading due to the large area...
Hokie66 - You describe "just taxiing" as a more severe case of loading than 'landing'... Is that official or just hearsay?
I am not familiar with the design of pavement slabs for aircraft wheel loadings, so I am just thinking it through... I agree that air speed over the wing generates uplift...
Slightly off the issue of 'stamping' reo drawings (and maybe more directed only to Australian engineers) - why is it NOT common practice in Australia to review conventional formed slab reinforcement schedules/shop drawings? We review structural steel shop drawings, post-tension shop drawings...
From my understanding the new FEM 1.005 code basically accounts for out of service wind load case also coming from the front (i.e not relying on the crane weathervaning). I think the wind speeds are still 10 min average. This will significantly increase base overturning moments for new cranes...
I too have come across this question whilst looking at wind loads on tower cranes.
I found the tower crane manufacture supplies the out of service base foundation load due to an average wind speed (over a minute or 10mins etc) rather than a gust for stability calculations. I realise that some...
I believe it is good detailing in concrete T-beams to put the reinforcement in the top of the flange region in negative moment zones. This maximises internal leverarm, ensures access for good compaction of concrete in the web and provides good crack control in slab surface.
But like ishvaaag...
The slip joint between PT slab and shear walls is also to account for the 'shortening' of the slab in the stressing process and to ensure the pre-compression gets into the slab (as well as initial shrinkage you noted).
I normally use a oversized grout tube over the starter bars from the wall...
If there is insufficient weight or lack of hold down in a structure to prevent overturning, the strucure will lift off its foundation to uplift the structure above. This cyclic movement will cause rocking of the structure.
This can be used as a form of energy dissapation in seismic analysis...
We design the pre-cast (thickness and reo) to satisfy the 'in service' or 'once installed' loads (ie. wind, LL etc).
Any details that relate to the erection of the panels need to be provided by the precast manufacture. Ie. Any lifting eyes or additional reo for lifting etc
I have thought about this problem and discussed it with tradesmen on site. My conclusions are 'non-loadbearing' walls that finish short of the underside of truss (to allow the truss to deflect) are not a good idea. There are just too many trades that need to be informed of the detail (that are...
I have used Ancon shear connectors on jobs - They can be handy especially for PT slabs. But they are expensive and require specific reinforcement detailing around them.
I'm not sure if the OP question was answered however - Is there a calculation that can be done to determine concrete failure...
