Saddle information

[Knowledgeseeker101]

Hey,

I need some assistance in this, my mind can't seem to probably figure it out the right way. Anyways here is the issue, I was asked to create an excel calculator to calculate what Saddles size would support a vessel with a specific size. anyways so i did my due diligence, after extensive work on the excel and some head bangs on the wall i did both calculators for the Zick analysis for a two support saddle, and I did another sheet that works on vessels that requires more than two saddles. My boss came back with " no this is not what i am looking for, I am looking for an excel calculator that i would give the field guys who are not engineers and all they have is a measuring tape for which then they would put in the height, length , and width of the available saddle that is in front of them and it would tell them what kind of vessel it would fit." Am i missing something here ? How does that work I can't seem to figure this out anymore. I didn't find any standardized table for saddles.

I would appreciate the help and assistance in this or guidance to what i should be looking at/for!

Thanks in advance

 

[BAretired]

My boss came back with " no this is not what i am looking for, I am looking for an excel calculator that i would give the field guys who are not engineers and all they have is a measuring tape for which then they would put in the height, length , and width of the available saddle that is in front of them and it would tell them what kind of vessel it would fit."

Height, length and width of saddle would not be enough to determine the dimensions of the vessel it would fit. You would also need the curvature of the saddle which would immediately tell the field guys the diameter of the vessel to be supported. The length of vessel would be a function of the length of saddle parallel to the axis of the cylindrical vessel.

BA

 

[Knowledgeseeker101]

Height, length and width of saddle would not be enough to determine the dimensions of the vessel it would fit.

.

I did tell my boss that but he said no it is possible, I recently graduated and this is my internship so I'm working hard to not mess it up. Even for the curvature of the Saddle i don't think they are capable of calculating that just by using measuring tape and getting the dimension at least in my opinion this is not doable. My mind still thinks there is a lot of variables included into it for example structural integrity of the vessel and etc...

The way I see it this will cause huge liabilities on anyone, If none engineers would take it that way what if they had no common sense and thought of a wood saddle is actually capable of withstanding a vessel that is 940 Te and is 10 ft wide. This is just a random example I'm still scratching the back of my head and see what i can do if i reanimate a saddle at home and find an actual way of calculating that need.

 

[oldestguy]

I'd look at preparing a chart from which they can pick off dimensions for the tank. I'd not expect field guys to do any calculating even if it is just entering numbers in a hand held device.

 

[Knowledgeseeker101]

look at preparing a chart from which they can pick off dimensions for the tank.

How can something like that be proposed since my boss is insisting on this kind of excel calculator?

I understand none would expect the field guys to do any calculations but with that being said since I am trying to secure the job. I am trying to be a successful robot where i get a task done in anyway possible. I don't know how to approach this anymore. The thing is not a single Tank is the same I looked at some of the previous transported Tanks(of any kind) they all have different dimensions different radius different structural design different equipments and we don't usually get this much details on the item that we need to transport most of the saddle chosen for the job is the recommendation of the Client or the Client had already prepared it and weld it into the tank.

Sorry if rattling a lot but I am in frustration mode and don't want this to put me down.

 

[SlideRuleEra]

...all they have is a measuring tape for which then they would put in the height, length , and width of the available saddle that is in front of them...

Perhaps the boss has a different definition of "height", "length", and "width".
If "height" and "width" are defined as shown below, (theoretical) tank diameter can be determined.

If "length" is the distance between saddles, maybe the tank length.

http://www.SlideRuleEra.net

 

[IFRs]

If you throw a tape across the saddle, you can measure the size of the opening of the saddle.
If you measure from the middle of this tape to the lowest point of the saddle you can calculate the diameter that fits inside that saddle assuming the saddle is circular.

Since you can't predict how long the vessel can be between saddles without knowing a lot more about the vessel and its design conditions, the saddle itself and the foundation you are done.

A very simple Excel worksheet can be developed for the vessel diameter based on the two measurements.

Would this satisfy your boss?

 

[John2025]

Well, I don't think it would be hard to calculate the diameter if they measured the chord length and the rise, but other than that I've got nothing.
Sheesh, in the time it took me to do the math, 2 other guys posted. I'm way too slow for Sliderule. well at least: D=Rise^2+(Chord/2)^2/Rise

 

[Knowledgeseeker101]

Perhaps the boss has a different definition of "height", "length", and "width".

If only that was the case HAHA. He actually drew the saddle for me which I'll post a link off. Warning "Don't laugh" because it cracks me up everytime i look at it.

A very simple Excel worksheet can be developed for the vessel diameter based on the two measurements.Would this satisfy your boss?

I'm going to attempt that in the meantime that might buy me some extra time.

Thank you all for the suggestions and guidance.

 

[Knowledgeseeker101]

Sheesh, in the time it took me to do the math, 2 other guys posted.

wait until you test me. Slower than the turtle lol.

D=Rise^2+Chord^2/Rise

I will attempt what you have proposed and what IFRs proposed also.

I guess buying myself sometime will help me through out this I'd rather submit something than taking me days/week to get what he needs done.

 

[Ron]

Is your boss an engineer? That sketch makes no sense for what he is asking....as you well know! Shocking if he's an engineer.

The sketch provided by slideruleera (SRE) is the proper way to look at this, and yes, you can calculate the diameter of the tank from that information alone. My first job out of college was designing long steel tanks for water and wastewater treatment systems (package plants). Many of them were installed on saddles (almost all of the water plants and some of the wastewater plants) and the saddles were relatively easy to design and build. We fabricated everything from steel, including the saddles, so we had to know those two measurements that SRE showed so that we could fabricate the saddle to the proper radius of the tank. Obviously any addition to the saddle width beyond the chord length has nothing to do with the tank size. The height as sketched by your boss only defines how high the tank sits off the ground....doesn't help in determining anything about the tank size.

 

[BAretired]

I did tell my boss that but he said no it is possible, I recently graduated and this is my internship so I'm working hard to not mess it up. Even for the curvature of the Saddle i don't think they are capable of calculating that just by using measuring tape and getting the dimension at least in my opinion this is not doable. My mind still thinks there is a lot of variables included into it for example structural integrity of the vessel and etc...

The distance from horn to horn of the saddle is a chord length of a circle and can be measured, say 'L'. The distance from that chord to the bottom of the curve can be measured, say 'h'. Diameter 'd' can be calculated from those two measurements. Field personnel should be capable of making that calculation but if not, you can provide a chart showing values of 'k' plotted against L/h where diameter of vessel is k*L.

The maximum length of vessel supported would depend on several variables, including wall thickness, reinforcing rings if applicable, head shape and density of fluid within the tank to name a few. As a starting point, you might consider only properly designed tanks without reinforcing rings, with specified head shape and specified liquid density.

Rather a difficult assignment for a recent graduate, it seems to me. Is your boss an engineer?

BA

 

[oldestguy]

so far I have not sen the formula.

 

[Knowledgeseeker101]

Is your boss an engineer? That sketch makes no sense for what he is asking....as you well know!

Unfortunately, He isn't an engineer experience in the industry that i work in got him that position.

Rather a difficult assignment for a recent graduate, it seems to me. Is your boss an engineer?

No. That is making it difficult for me too because i don't want to risk starting an argument with him whether I am right or wrong on any of the given tasks that I'm handling. In a way I'm taking that as a challenge for myself, but till what extent.

As for the newly graduate, my first task was to calculate stability,tilting angle, force on each tire and Chain Lashing to secure a 730 Te piece on two SPMT's one with 12 axles and second with 10 axles.

[highlight #FCE94F]PS: I did not even know what the hell was an SPMT lol.[/highlight]

 

[BAretired]

Using oldestguy's nomenclature:

(c/2)[sup]2[/sup] + (r-h)[sup]2[/sup] = r[sup]2[/sup]

c[sup]2[/sup]/4 + r[sup]2[/sup]- 2rh +h[sup]2[/sup] = r[sup]2[/sup]

c[sup]2[/sup]/4 - 2rh = -h[sup]2[/sup]

so 2r = c[sup]2[/sup]/4h + h

Since 2r = d, d = c[sup]2[/sup]/4h + h

If the field guys measure c = 6.0'; h = 1.5'
then they should be able to calculate d = 6*6/(4*1.5) + 1.5 = 7.5'

BA

 

[BAretired]

PS: I did not even know what the hell was an SPMT lol.

If it makes you feel any better, I would not have know what an SPMT was either until I checked with Google; and I practiced engineering for over fifty years. I do recall now that an SPMT was used to move the ill fated concrete truss into place prior to its collapse at Miami, Florida earlier this year.

BA

 

[IFRs]

The versine or rise may be harder to measure than we think. In your boss's sketch you could show "h" representing what you really want but also add a "d" that is from the base of the saddle in the middle of "c" and at the same elevation as the bottom of "b" up to the bottom of the saddle curve such that "b" minus "d" is the "h" that what you really need. Don't tell him why you need it...then blow his mind with a cute XLS with maybe a dynamic image!!! I'm not happy with this indirect measurement especially if the base of the saddle is not flat or obscured by dirt, grass, steel, concrete, etc but, you do what you can do. Remembering garbage in / garbage out, I'd also perform a sensitivity analysis so you know how plus/minus in each field dimension affects the result. Your Excel might want to offer a plus/minus error band based on, say, 1/2" error in each dimension.

 

[Knowledgeseeker101]

show "h" representing what you really want but also add a "d" that is from the base of the saddle in the middle of "c" and at the same elevation as the bottom of "b" up to the bottom of the saddle curve such that "b" minus "d" is the "h" that what you really need.

I like the way you are thinking about this. I might just do that. In general, I'll keep you guys posted and I'll share what I end up doing in excel.

A general question: Is it worth getting a NCCO Rigging Level I & II certificate ?

 

[Knowledgeseeker101]

If it makes you feel any better, I would not have know what an SPMT was either until I checked with Google; and I practiced engineering for over fifty years. I do recall now that an SPMT was used to move the ill fated concrete truss into place prior to its collapse at Miami, Florida earlier this year.

Haha yes it did.

Using oldestguy's nomenclature:

(c/2)2 + (r-h)2 = r2

c2/4 + r2- 2rh +h2 = r2

c2/4 - 2rh = -h2

so 2r = c2/4h + h

Since 2r = d, d = c2/4h + h

If the field guys measure c = 6.0'; h = 1.5'
then they should be able to calculate d = 6*6/(4*1.5) + 1.5 = 7.5'

I'm working on it now Thank you for the help I will share my excel sheet here once i complete it based on that and see what my boss says.

 

[SlideRuleEra]

I recently graduated and this is my internship...
Is it worth getting a NCCCO Rigging Level I & II certificate ?

Do you have significant experience with the field use of cranes in a working environment, perhaps from before college?

http://www.SlideRuleEra.net