structural planning/ structural scheme ( science of placing beams and columns) 3

[Shazeb Mirza]

Hello everyone, I hope you people are doing great.

1)can anyone tell me what is the main idea that comes to mind when going for a structural scheme (the science of placing beams and columns)

2)can I get reference/notes or tips which i can use in my futures?

thanks

 

[rb1957]

apologies, but "good grief" !

AFAIK, columns and beams are initially placed by the architect, who has a vision of the building.
Then the structural engineers analyze the building with loads from the various codes to define the sizes of these elements.

Sometimes, everything is good, the sizes fit with the architect's intent.
Often, there are problems with the plan, the architect cries, and then everybody gets around a table to figure out how to solve the problem.

Then the guys pouring the concrete and manufacturing the beam and columns eff things up so the structural engineer is called. he cries, then everybody gets around a table and figures out a solution.

another day in paradise, or is paradise one day closer ?

 

[Shazeb Mirza]

then who is happy bro? @rb1957

I was just curious how a person decides where to place a beam and where to place the column. There must be solid science behind those decisions

 

[Enable]

Some form of reason? Yes. Scientific? No.

The answer naturally is that it depends. If you've been given a set of architectural plans, well those plans dictate where columns can go based on where you can (mostly) conceal them. If you have free reign then your layout will be based on experience. You'll recall what has worked for you in the past for similar structures under similar conditions and use that as a starting template.

I mean, if the world was run by structural engineers every building would be a symmetric box and columns spaced at quite regular intervals. Great for torsion, lots of redundancy, easy to analyze, perfect! Except nobody wants a world full of boxes. So we deviate from this but actually that's where you pretty much start.

Start with a box with column spacing based on allowable spans of your floor material, and incrementally get more bold as desired / needed based on architect / owner.

I told you...rational not scientific!

 

[rb1957]

the point is that the structure is a combination of design and science. There is nothing that says "the spacing of thy columns shall be 10' (or 3m); no more, no less".

A column is only a structural element when it has been sized. If an architect wants a big open space, then the columns and beams will generally be much heavier than if there are many columns.

have you tried google ? This site is intended for professionals, asking professional questions.

another day in paradise, or is paradise one day closer ?

 

[KootK]

A very incomplete list of guiding principles to get the ball rolling:

1) Vertical structure is usually pretty cheap so one kind of wants as much of that as possible given the architectural constraints.

2) Often you are trying to work with a particular floor system at a particular depth in order to produce overall economy. One spaces beams and columns as best they can to make that floor system work.

3) Often you are trying to provide open "lanes" within which to run MEP stuff which will inform your structure layout.

4) In continuous floor systems, like concrete slabs, it's sometimes advantageous to have your end spans a little shorter than your interior spans in order to equalize moments some.

5) In concrete slabs, it is sometimes advantageous to hold columns back from the free edges a bit to help with punching shear.

6) You want to keep connections and formwork simple so rectilinear arrangements and repeated sizes are nice.

7) Perimeter column spacing will often by impacted by the detailing of the building skin and associated deflection requirements.

....

It can sometimes be a frustrating exercise for engineers who typically seek a "right" answer. On the other hand, it's exactly this kind of creative synthesizing of criteria that may offer us some short lived reprieve from the onslaught of our artificial intelligence competitors.

 

[dik]

A lot of the buildings I've been involved with, are single storey steel framed. I don't have an architect attached... it depends on the building area required and the spacing of the columns the client wants. Generally first attempt is roughly 25'X40' bays with the 40' being the span of the OWSJ. Spacing can vary considerably. I generally start with a joist depth equal to 0.7" / ft... so most economical depth for a 40' span would be about 28" deep... this depends on your snow loading requirements.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[JLNJ]

If you are designing a football stadium, do not put columns in the middle of the field.

 

[rb1957]

sure ... home field advantage.

another day in paradise, or is paradise one day closer ?

 

[dik]

Paint them safety yellow with black stripes...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik