simple point load formulas needed 1

[Gunner77]

Hi, I am a Project Building Services Engineer and require some simple formulas for calculating the size of steel sections for supporting pipe, duct and plant etc. So point loads and spread loads etc. Some structured reading would also be useful.

 

[GalileoG]

I hope you have your flame retardant coveralls with you because this forum is going to give it to you real good.

Clansman

 

[kslee1000]

I am a site structural engineer/manager overseeing hundreds, if not thousands, of equipment and supporting/sheilding structures, but I wouldn't put my hands on anything I wasn't equipped to do even within my own discipline.

However, you may benefit from owing a structural handbook that covers general aspect of structural engineering to gain understand of basic structural behaviors, and assist you in making better decisions. Do a search on the web, you will get quite a few good ones that match your need, and may help you in the long run.

Too many to suggest. Good luck.

 

[Ron]

If we were able to boil down 4 or 5 years of engineering school, 3 or 4 years of internship and at least 2 licensing exams into a few sentences and tables, we'd be magicians, not structural engineers.

Call in a licensed structural engineer or licensed mechanical engineer to do this for you....and while you're at it, drop the "engineer" from your title. It violates state law in most states.

 

[slickdeals]

I hope you have your flame retardant coveralls with you because this forum is going to give it to you real good

And so it begins....

 

[msquared48]

6 years of school, 6 years of internship (4 Civil and 2 Structural) and three exams totaling 32 hours, 30+ years of experience.

Ron, reaqlistically, I think you'd have a problem with eliminating the term "engineer" here as it is a well used, long standing term in the maritime, military, manufacturing, and maintenance industries. I think the distinction though is partly being college educated in a specific engineering discipline, but mainly in the specific context of a LICENSED PROFESSIONAL Engineer in a specific RECOGNIZED AND REGULATED engineering discipline. Such is not the case in the terminology used in the four cases mentioned above.

I do understand, however, that the perception of the general pubic is a problem here, with the vast majority unaware of any distinction. It is up to us as Licensed Professional Engineers to make that distinction and educate the public, our clientelle.

Mike McCann
MMC Engineering

 

[Ron]

Mike....I agree, it is a common term to be used in those areas. Just a pet peeve of mine when contractors and others bank off the title. This single point alone has cost our profession in credibility and professional stature.

 

[kslee1000]

Engine-er. (Train operator?)
I think this term was broadly applied to the skillful, crafts person, since the invention until modern day. Interesting to note how much our profession has advanced and changed.
Given another 100 years, I guess this title will belongs to people know how to work on computer, interpretate the out put, and check against code, maybe draw a line or two by CAD.
I am long gone by then. LOL

 

[Gunner77]

I feel the above threads have enabled people to vent some frustrations that have built up over the years...I can understand your points and do sympathize with your predicament. Mike, in your case 12 years of input from your self to have the title of Engineer, I understand. The reason for me asking the question has derived from the points you all made above. Let me elaborate on my role. We obtain a Building Services Contract from a client, normally a Construction Company, but more often a Construction Management Team or Land Developer. We receive a 'design', a term, that due to Consultants Fees being put under considerable pressure is used very loosely, more like a design intent. It is then my job to interpret this design and check that it works. Process this information to ultimately give an installation that achieves the design intent. This is then taken by our Construction Manager given to the on site Supervisors, Foreman and Charge hands and built by the Fitters, Welders, Plumbers, Duct Erectors, A/C Installers, Controls Specialists and Electricians. If I,m not an Engineer, then fine, it doesn't worry me, the above day does not change as a result of interpretation. Anyway, the reason for me writing the first thread was that in one particular instance I have to support a 30 Meter run of pipework, three lots of pipes to a range of Chillers. The sizes are 250mm dia 200mm dia and 150mm dia, each of the three rows under slung. I gave the weights of full pipework to our Structural Engineer on site, he then produced a framework that would support the installation. The 'design' I received back was, on the face of it, so over the top it was laughable. My intention now is to gain an extremely basic knowledge of the types of material, sizes and the loads they are capable of being put under and the support spans that are required in order that I can question situations as above. Anyone, in my view can look at the types of mass I deal with and assign a monstrosity to support it, its called 'over engineering', historically us English are good at that, its what I'm trying to get away from. If what I am asking for is not available then please feel free to say so, but can we please be polite.

 

[SlenderBeam]

Ron,

Get a second structural engineer's opinion.

Just like you would if you questioned your doctor's opinion.

There's no difference.

 

[Einsteim]

I agree fully, get that second opinion. Shouldn't cost much to have another firm or individual that is a PE do a peer overview. If he or she feel it is "overkill" by first look, then maybe a more thorough (and costly) review or redesign is warranted. I don't think you will find anybody willing to train you on how to design the necessary support via this website. But, if you think the original engineer overdesigned, get that second opinion and justify your existince to whoever your client is.

 

[Ron]

Gunner77...First, I offer my apology for being harsh. The phrasing of your predicament seemed to shout "just show me a couple of tables and I'll design this thing....health, safety and welfare of the public be damned"! Your second posting shows that you have a legitimate request so that you may learn more about the systems and assist your team in making better decisions. I respect that and offer the following:

Go back to the structural engineer who designed the support system that you deem "overdesigned" and speak with him about it. Ask if it is fully necessary, considering the task, and have him explain his design and why he considers it necessary. Unfortunately some engineers ascribe to the old saw "When in doubt, make it stout" (the structure, not the beer). Hopefully he has reason for the design.

If he cannot or is unwilling to do so, then seek a second opinion. Keep in mind, he might be making considerations for the system that you have not considered and that he must allow for in his responsibility. Further, remember that he is likely considering that he will have little input in the fabrication and construction, so must allow for many "unknowns" in his design. I'm not trying to defend "overdesign", just giving some perspective on where he might have made his decisions.

As for reference material, I would suggest that in your capacity you might consider at least two books:

...the first is the "Mechanical Engineers Handbook" by Marks
...the second is the Structural Engineers Handbook (can't remember the author and I'm not in my office)

Another book you might want is "Principles and Practices of Commercial Construction" by Cameron Andres. It is not highly technical and provides a general overview of many construction systems, foundation to roof.

Good luck and let us know how it turns out.

 

[msquared48]

I, too, understand the situation better now, as it was not divulged in your original post. It is a common problem with clientelle, sometimes wanting to do things in a less costly manner, and sometines at the expense of the liability of the structural engineer. Better ask if your SE has Liability (errors and omissions) Insurance, for a lack of it will make him more conservative in his approach. Again, too, availability of materials is sometimes an issue, as well as the feeling of competency of the engineer for the stgructrural design situagtion. In such instances, a simplistic or conservative approach is sometines taken, rather than a more difficult solution. With the advent of comnputers now though, I would consider that to be a non-issue.

Mike McCann
MMC Engineering

 

[csd72]

From another perspective. If the client wants to put more pipework on this beam in 6 months time and they have to replace the beam then this could be quite expensive. Sometimes being conservative can actually save the client money in the long run.

We had clients in telecoms that used to give us grief for being too lean for just this reason.

The beam may also have a long length with nothing to stop it buckling and it would therefore take much less load than would be aparrent to an untrained eye.

Also there is allowing for the deliberate disregard that some service contractors have for structural beams(cutting huge holes where there is a clash e.t.c.

Structural engineering is considerably more complicated than most people realise.

 

[civilperson]

The loading of pipe supports is as hard to calculate as the design of the support. "PipePro", "Caesar" or some pipe stress software will give pipe loads,(Thermal, dynamic and gravity in three axes and moment around the three axes) and then wind, seismic and test loading needs to be calculated with dead and live/fluid loads. Combine in combinations per the code and you are ready to start your design. Judgement as to what future loads to accomodate has been discussed in previuos posts and I used no more than 50% utilization for foundations and columns for future expansion, (90% or greater for beams with deflection as an added criteria).

 

[Gunner77]

All,

Thank you for the support. On review of my original thread I can see the trap I set up for my self. I appear to have made light of the processes involved in making the assessment. I will make the point of sending the information to two SEs' next time in order to make the judgment.
Ron, I will look up the books and set up some structured reading. Thanks once again.