Most Basic Guide To Structural Design

[BenjaminM]

Over the last decade I've seen various platforms, or pipe racks or stands or mezzanines which were more or less hobbled together by maintenance departments. In some cases the result appears to be way undersized and in other cases extremely over sized. Most of the time the structure in question was built with material on hand with no true design at all.

I'd like to develop a very basic understanding of structural design. How much weight can a vertical I-beam support, how large does a horizontal I-beam need to be for a given distance, what sort of deflections are acceptable or not, how to attach horizontal beams to vertical beams.

Ultimately I am looking for a guide to steel structural design for non-structural engineers. Please don't cringe too much, as I am not looking to build bridges, or sky scrapers, I'd just like to understand the most basic fundamentals of design.

Any references or suggestions?

Thank you in advance!

 

[WARose]

Over the last decade I've seen various platforms, or pipe racks or stands or mezzanines which were more or less hobbled together by maintenance departments. In some cases the result appears to be way undersized and in other cases extremely over sized. Most of the time the structure in question was built with material on hand with no true design at all.

Scary.

I'd like to develop a very basic understanding of structural design.

It's hard to just give that to someone (or to define "basic"). It's sort of like that Dilbert cartoon where the guy asks Alice to tell him everything she knows about engineering in 10 minutes.

How much weight can a vertical I-beam support,....

You mean a column? It can vary based on unsupported length......but for most shapes in the AISC manual and ordinary lengths (i.e. 0-40') you are talking several kips to several thousand. Usually I'm expecting several hundred (kips). (For most shapes I am use to using as columns.)

....how large does a horizontal I-beam need to be for a given distance,...

Most people start out with the span(in feet)/2 for the beam depth (in inches). In other words, if you have a span of 24 feet, you'd try something out of the W12 series. But it's (again) going to depend on unsupported length, loads, deflection, etc.

....what sort of deflections are acceptable or not,....

Again: it depends on what you are supporting. But most people limit Dead Load + Live Load deflection to L/240 (where L=span). Live load deflection can be limited to L/360. Sometimes restrictions on supporting masonry can be as low as L/600. The IBC calls out deflection limits at several points (see TABLE 1604.3 in the 2012 version).

....how to attach horizontal beams to vertical beams.

Depends on what you are trying to accomplish. Most commonly we are talking clip angles and bolted to both the column (to it's web or flange) and the beam's web for shear transfer. But if it's part of the lateral force resisting system.....you could use a moment connection. (I.e. the top and bottom flange connected with angles or welds, and you still have the web connection for shear.) Moment connections are not as popular as braced frames however (because of the cost).

 

[SlideRuleEra]

Basic Structural Engineering

http://www.SlideRuleEra.net

http://www.VacuumTubeEra.net

 

[MotorCity]

Just a few quick thoughts off the top of my head........

Rule 1: Make it SAFE!!

Rule 2: Sum of all forces and moments = 0

Rule 3: Stress = (force/area) +/- (moment*centroid distance/moment of inertia)

Rule 4: Make it LOOK right. (i.e. don't use a 4" tube for a 30' column, even if it works.)

Rule 5: Use repetitive member sizes and details whenever possible

Rule 6: Welded shop connections, bolted field connections

 

[JStructsteel]

Could you take a statics class, mechanics class, and then maybe a steel design class at local college?

 

[BenjaminM]

Thank you all for the quick responses.

jrisebo the thought had crossed my mind, while I am not looking to make a career of it, I would like to develop a general knowledge base of it.

SlideRuleEra I'd watched a few videos on YouTube but I tend to be a little dubious of the sources in general, I'll watch the ones linked in your search later today and see what I can gather.

WARose, scarier than you know in a few instances. And to the point of you can't explain everything in 10 minutes, I surely do not expect as much. I probably should have stated I am looking for a good entry level text book that would lay the general concepts out well. Any recommendations and I will chase it down on Ebay or Amazon.

MotorCity sums up the generals pretty well.

Thank you all again!

 

[SlideRuleEra]

myrdale - Agree, you will have to be selective... for basic videos.
There are more advanced that are professional level, such as "American Institute of Steel Construction (AISC) Education".

http://www.SlideRuleEra.net

http://www.VacuumTubeEra.net

 

[StrucDesignPE]

myrdale,
Might I suggest you get a copy of Structural Design: A Practical Guide for Architects by Underwood and Chiuini or Structure for Architects by Dabby and Bedi. These are both "primers" of sorts for structural engineering geared towards those with little to no experience in structural engineering. They both cover all the basics while the Underwood book gets deeper into design using steel, concrete, and wood. These books would certainly not make anyone qualified to design a building structure, but would help you become familiar with much of what is done in structural design. Links provided below.

https://www.amazon.com/Structural-D...ds=structural+design+for+architects+underwood

https://www.amazon.com/Structure-Ar...words=structure+for+architects+dabby+and+bedi