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I'm designing a Tower Crane, i'm using SAP2000 and all the elements passed, but i have a problem or a doubt with the deflection, in the top i have obtained aprox. 80 cm, the height of my tower crane is 80 metros, the AISC standards allow a ratio of 1/500, I just want to know if i m ok, or what do i have to do?
I have read in previous forum a ratio of 1/1000 but wher do i get that information? What standard allows it?
Thank you for your help,
Mr. Quality
This is a serious issue and it involves a lot more than simple deflection. A 250ft high crane needs to have safety factors designed into the vertical support.
The jib section traditionally has a traveling counter-weight on the tail end and deflection can be both up and down at any given time with uneven loads on each end of the jib.
This is a job for Structural Engineer well versed in crane design.
The following items are just a few to consider for Tower Crane design
[LIST][*]Design of all cranes should be based on the latest FEM standards [*]Attention should be given to the ‘latest’ changes in the FEM standards in design requirements, specifically the treatment of wind loading in the ‘In’ & ‘Out’ of service conditions [*]Natural frequencies of vibration and resonance effects must be considered [*]Fatigue Life Prediction & analysis is crucial [*]Correct Tolerance Specifications vary from component to component [*]Stress flow considerations at joints are very important [*]Material specs are critical and fine grain , high strength steels must be selected, A metallurgical specialist must be consulted. [*]Mechanical Engineers must play a bigger part in the design than Structural Engineers. Typically, Engineers that are specialists in this type of work [*]Fabrication procedures with high end fixtures are critical (big $$$$$ investment). The initial investment for fixtures testing etc... is much higher than the cost of a crane ! [/LIST]
And the list goes on ........
Thank you for your replies. I'll check the counter-weight. I'm considering as material ASTM A572 GR50, in some books they recommend it. I'm considering the combination loads on sap2000, QUAKE, WIND, LIVE, DEAD. The Lmax= is about 15 ton @ 3 meters from the slewing ratio. The jib is about 40 meters.
Mr. Quality
Might want to watch a few of these on YouTube. I really think you should get some Engineering help on this project.
[url]http://www.youtube.com/results?search_query=building+crane+failure&oq=building+crane+failure&aq=f&aqi=&aql=&gs_l=youtube.3...591.4042.0.4181.22.11.0.0.0.0.0.0..0.0[/url].
Thank you,
I was thinking about The deflection at the top (h=80m) is 80 cm. But in that case AISC allows me 16 cm. But I think is very strict for Celosia.
Thanks for the link,
[QUOTE=Mr. Quality;2808]Thank you,
I was thinking about The deflection at the top (h=80m) is 80 cm. But in that case AISC allows me 16 cm. But I think is very strict for Celosia.
Thanks for the link,[/QUOTE]wer
Mr. Quality,
It is good to know you are working on the tower crane design. I am newly working in to the tower crane design. I need to know, what is the test will perform at tower crane manufactures end. Do you have any standards for that.
We desperately looking for the testing details for the tower crane.
Design and manufacture according to the Machinery directive and other main relevant directives applicable to Tower Cranes,
[FONT=sans-serif]Electromagnetic Compatibility directive
Noise Emission directive
Low-voltage directive
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