m_naeem_b

Dear All,
Is there any one who know, how to design Pre-Heater tower of 80m height of any cement factory in ETAB?
Means what type of forces will apply in ETAB?
What will will live laod and dead load apply in ETAB?
what will be the load combination? etc
I made simple model of structure, but didn't load load yet..
I am waiting your kind reply

Aoa.
 
Internet is a wealth of information, including structural.  A smart search on the internet, may help you collect pre-heaters related general information, design procedures and calculations, as well as relevant design codes.

You need to know the loaded area, and decide accordingly about taking the affect of that particular load as point, or UDL.
If you are not sure, make two models with different types of loadings.

I did a Google search to see what it looks like.  I am also attaching what I got to make sure that we are on the same page. To design something like attached below, you need to have the operating weight of the machine and pipe-stress analysis report that provides you with stress loads at each location where the pipe is located. You need to make sure that the structure is designed for wind drift less than H/200 and seismic drift less than the applicable code. These structures are very common in EPC Industry. Normally, the vendor provides the maximum operating, empty and hydro test weights along with max shears due to wind and seismic. Ask your vendor for this information and proceed with design.
 
Please post your follow up questions.
 
Thanks.
 
 

The geotechnical engineer has to provide you with soil improvement recommendations for liquefaction.

Aoa.
 
Naeem!
 
I have done a little search on google regarding design examples for lifting hooks and devices, and found following links on the first page of search results. There will be a lot more on later search pages as well.  (mostly the designs data is based on ASME BTH (Below The Hook) 1 code)  :
 
1. spreader bar and lug caculations: http://www.pveng.com/ASME/ASME_Samples/ASME_SpreaderBar/ASME_SpreaderBar_Calcs.pdf
 
2. Lifting lug design:  http://www.webcivil.com/stlug.aspx
 
3. Spreader bar design process: http://www.spartaengineering.com/spreader-bar-design-process/
 
4. Below the hook equipment. Has several pdf files about lifting devices.: http://www.avonengineering.com/below-hook-lifting.php
 
etc. etc.
 
Try searching yourself. You may surely get much more relevant data than I have listed above. 

The lifting lugs are available from 3rd party and their max capacities are listed. You just need to see that your lifting reaction at that point is less than lifting lug capacity. What you need to do is to weld a steel plate to reinforcement cage and lifting lug could be attached to the plate. This is a improvised solution. I have never done a rebar cage lifting but I do have done steel module lifting calculations. Weld specifications would depend upon your base metal strength. I am out of office. Can post somethinh when I return to Canada from Pak.

Aoa.
 
I have not designed lifting hooks. However, in principle, design of hooks and lifting arrangement should be done in a way, similar to the design of a steel frame. (Deciding a suitable layout for the lifting device and hook., calculating total load to be lifted, determining members, welds, and stiffener sizes , depending upon load distribution to various members and joints...)
 
Design of these lifting devices and hooks, is generally to ensure safety of work people during construction. In USA, generally, OSHA regulations provide basis for the safe design of these devices.
 
A good search on the internet might help you collect specific details relevant to your requirement.

I have received the following reply from my teacher, Dr.Farhat.
"Personally I believe that the foundation should be taken down to competent strata using piles. If the reclamation site is near sea shore and dredged material is used then it must be assessed for liquefaction and hetrogeneity."
Hope it helps.
Thanks.

Here is updated description with more information. See the attached image.
 
Thanks.
 

Here is what we do in Canada as per S16; Design your pile as a beam column. You can download the Canadian Handbook from google. Just search CISC Steel Handbook.
 

 
Thanks.

Dear:
 
I also never design helipad. But , I have some material regarding this. see attached file.  When you designed helipad, kindly share your knowledge or models or drawings in this forum.
 
File with name " Workshop2011" is more effective for new user on this topic.
HELIPORT DESIGN AND PLANNING.pdf
HELIPAD_Loads on Helicopte.pdf
1607.docx
chapt04.pdf

Dear:
 
I also never design helipad. But , I have some material regarding this. see attached file.  When you designed helipad, kindly share your knowledge or models or drawings in this forum.
 
File with name " Workshop2011" is more effective for new user on this topic.
HELIPORT DESIGN AND PLANNING.pdf
HELIPAD_Loads on Helicopte.pdf
1607.docx
chapt04.pdf

Dear:
 
I also never design helipad. But , I have some material regarding this. see attached file.  When you designed helipad, kindly share your knowledge or models or drawings in this forum.
 
File with name " Workshop2011" is more effective for new user on this topic.
HELIPORT DESIGN AND PLANNING.pdf
HELIPAD_Loads on Helicopte.pdf
1607.docx
chapt04.pdf

Naeem, your model is incomplete. There are no load cases defined other than dead. Wind will govern the design for the structure. You members are almost all overstressed in basic gravity load combinations. Your should provide complete braces to the foundation so that for all lateral loads (esp wind) load path is complete and there is no bending in the framing members. I should have seen this way before but I am sorry due some unexpected work I couldnt check it. Anyhow, revise your framing. Put cross-braces or chevron bracing on all faces instead of knee braces; that will make your forces from top to bottom through tension and compression and you dont need any moment joints. Apply wind load (v.v. imp) . if you dont know how to do it let me know. I can help you for auto loading in SAP. Your model needs a lot of rework.

I have started looking at it. Hopefully will be done by this weekend. 

I will check your RISA Model and get back to you on this. Do you have any further details about the working of chair lift system as Syed asked ?
 
Thanks

Can you please make me understand the process of movement of the chair lifts. How it is controlled? Is there a single cable that starts from one tower and takes a round over the rest of towers with pulley action, i-e, the single cable becomes the part of both Up-Way movement and the Down-Way movements?  Or there are two independent movements going on, i-e, the Up-Way and the Down-Way separately? If two separate movements going on (involving the two opposie set of towers) then within each system where are those pulleys located that turn the motion of cable by 180 degrees? OR Will those pulleys be apart from both the towers? I just want to think about the transfer of lateral load of the chair lifts to the towers during motion as well as at static conditions. Of course slope is one of the factor that will generate a component of lateral load but apart from it, is there any pulley reaction transferring to the columns?
 
Regards

Dear Engineers,
 
Without going into any in-depth design I have just checked roughly the steel column size required for the stability concern, i-e, the size required to keep the slenderness ratio (k l/r) within 200, it comes out to be around 36 X 36 inches X 1/2 inch thickness, which gives the slenderness ratio of 187. I am not sure about the thickness requirement at this stage because it will also be governed by the fulfillment of strength requirements, i-e, the design load-moment interaction. I believe that every code has the stability requirements (The slenderness limitation), depending upon the importance of the compression member itself, it may sometimes be less than 100 in some codes, better to check with the code upon which the design is being carried out. I took the height of column as 150 feet and assume "k" as 1.5, which may increase depends upon the boundary conditions at column top. I suggest that a truss type of column be selected and also to keep in mind the workability / Installation process while designing these columns.
 
Wish you good luck

Thanks for sharing the drawing in pdf format. I am writing down a design approach, and would request everyone to throw their comments and questions. Lets start by:
 
1) Design Criteria
2) Expected loads on structure
3) Possible limit states
 
1) Design Criteria
I believe that you have been working on this for some time and will be having a design criteria outlining what code do you want to design this structure on, and what material strengths do you intend to use. Please post the design criteria document here.
 
2) Expected loads on structure
The structure is a pair of columns, with motors installed at the top of the that push/ move the chair lift. I would recommend that each column pair would be joined and braced at different levels to provide a stiff support (how far are they ? ; present framing doesn't look to work, I would suggest a truss tower). Possible loads are: Weight of motors. Possible thrusts at starting and stopping of chair lifts or when faced with load shedding. Weight of chair lifts and passengers (considering number of persons and chair lifts at a given time). Wind load on columns. Weight of cable and its reaction on columns. (Cable are eccentric from column center) 3) Possible limit states
Apparently, columns need to be laterally stiff enough to maintain tension in the chair lift cables.  Uneven support settlement. Utilization of piles to be kept to 60% and under to avoid that. It also depends upon various factors, but I am just throwing in a bullet. Maximum unsupported length of cable. You many wanna do a check on that to make sure things outside your scope don't fail. I remember, we did a problem in Theory of structures for a suspension bridge. Similar concept. Overturning Check. Shear failure of piles. (throwing in a bullet) Anchor Bolt Failure. (from sketch it looks like anchor bolt shown are typical and not designed) Frost Jacking. You can use a higher importance factor as failure can be catastrophic. Some other questions.
How good is the geo-technical data ? Please share: what you have done till now. Also list things that you haven't designed and are using typical details. Are anchor bolts designed ? Are piles designed properly ?  How are you calculating wind load ? what code ? are you doing any manual checks on that or just software ? What is the seismic class of the site ? Are there any structures near by ? How high is the water table ? What is the confidence level on structural steel available ? Local from a mill or properly tested sections. Is the soil subjected to frost heave ? Are piles and pile cap designed for that ? Are piles concrete or steel ? Do you have more drawings to share ? You foundation looks inadequate ? Free standing columns(present framing) would be out of proportion. I would Suggest having a Truss Tower; load path would be robust and your site construction would be easy and cheap too. I would welcome comments and more questions. Naeem, I am looking forward to your reply.
 
Cheers.

I haven't done something ditto to what you are explaining, but I would like future information on this being shared, so that, may be, we can develop something ?
 
Thanks.

you have add shearwall.. or increase the size of column.... change the framing to satisfy the drift value under allowable... your model of "center of mass and center of rigidity" should be as near as possible....
due to this... your model torsional irregularities and drift will become under limit. 

no waqar...you can sing the song..but at the same time can increase the stiffness of your building...to reduce drifts....it will be a good combo!

this is not exactly a thumb rule...its written in code commentary of ASCE 7-05 chapter CC3 or 2 i think...
 
building drift should fulfill this requirement unless you are sure that the building is more ductile and can satisfy other limits for example H/200 etc...
 
 
but remember this one check only for wind and the wind is service is here...
 
you need to satisfy inter stroey drifts too for wind..and you can consider the limit to be 10mm
 
similary you need to satisfy seismic drift of 0.025 or 0.020 and also the vertical and horizontal irregularities of the building in seismic design...
 
close your eyes and just sing a song

its name of a book/ document.