AISC / ASD Tables

[Suns Den]

Can any one post the required tables from AISC/ASD for the am structural test questions.

AISC/ASD - Manual of Steel Construction Allowable Stress Design, Ninth Edition, 1989.

Also what method does Chelapathi books follow ASD or LRFD?

Thanks!

 

[kevo_55]

Sun,

There's too many to post. You should just go out and buy/use a copy of ASD.

I'm not too sure about Chelapathi.

 

[Suns Den]

I look at the practice problems, I can look at the solution and (may be) figure out but solving some of them have been nightmare. Which method to use, what clauses Grrrrrrrrrrrrr.....

NCEES FE reference seemed good initially but it looks like a another mess now with both ASD and LRFD methods cramped in and some half a@# tables. It also refers to tables in methodology and formulas that are not in there...

any suggestions are appreciated to approach some of the Structures questions.

 

[MA_PE]

I look at the practice problems, I can look at the solution and (may be) figure out but solving some of them have been nightmare. Which method to use, what clauses Grrrrrrrrrrrrr.....
NCEES FE reference seemed good initially but it looks like a another mess now with both ASD and LRFD methods cramped in and some half a@# tables. It also refers to tables in methodology and formulas that are not in there...

any suggestions are appreciated to approach some of the Structures questions.

Pretty fundamental but are you aware that:

ASD is "Allowable Stress Design" or Working Stress Method meaning that you compare service (unfactored) loads to an allowable stress level (the design is based on a service load capacity, for example allowable bending stress is typically 0.66Fy) and the

LRFD (Load and Resistance Factor Design) is an Ultimate Stress Method where you compare factored design loads to the ultimate capacity of the member (using the same example bending stress would be limited to 0.9Fy).

Thus if the appied load are factored you're dealing with the LRFD method. If they are not factored then you're dealing with the ASD method.

Hope this helps.

 

[IlPadrino]

Can any one post the required tables from AISC/ASD for the am structural test questions.
AISC/ASD - Manual of Steel Construction Allowable Stress Design, Ninth Edition, 1989.

Also what method does Chelapathi books follow ASD or LRFD?

Thanks!

I might have something that can help... I need to scan them in, though, and then post them to a wiki. Give me a few days.

 

[Suns Den]

Pretty fundamental but are you aware that:
ASD is "Allowable Stress Design" or Working Stress Method meaning that you compare service (unfactored) loads to an allowable stress level (the design is based on a service load capacity, for example allowable bending stress is typically 0.66Fy) and the

LRFD (Load and Resistance Factor Design) is an Ultimate Stress Method where you compare factored design loads to the ultimate capacity of the member (using the same example bending stress would be limited to 0.9Fy).

Thus if the appied load are factored you're dealing with the LRFD method. If they are not factored then you're dealing with the ASD method.

Hope this helps.

Thanks MAPE

How would we analyze if a beam is over/under, balanced, doubly reinforced?

F=(bd^2)/1200 what is the function of this formula?

 

[kevo_55]

Oh man,

You're not talking about structural steel design. You're talking about concrete design.

Is that right?

 

[MA_PE]

How would we analyze if a beam is over/under, balanced, doubly reinforced?

As kevo said, this question appears to be addressing a reinforced concrete beam. The ASD/AISC is a steel manual. so there is some confusion, however the "beam tables" included in the steel manual are generic to beam analysis and can be used to get the forces out of a beam of any type. So if your analyzing a concrete beam for example: simply supported with a concentrated load at the center - then you could use the beam tables in the steel manual to get that the maximum moment is at the center and M=Pl/4. You can then design a concrete beam to carry this moment. Is your initial post asking for the beam tables?
over/under, balanced, doubly reinforced?

"over/under, balanced" are steel reinforcing (rebar) limits to a concrete beam. Over reinforced means that steel area is greater than the maximum allowed (no ductility), under reinforced means that the steel area is below the minimum requirement. "Doubly reinforced" means that you have compression and tension (or top and bottom) reinforcing steel in a concrete beam.

Concrete can be designed by the WSD (working stress method) which takes the same approach as the steel ASD or by the Ultimate Strength Method (the same appraoch as the LRFD). FYI, it is my experience that concrete is typically designed based on ultimate strength but the WSD is still in the books.

F=(bd^2)/1200 what is the function of this formula?

I don't immediately recognize the format of this equation. What value is it supposed to calculate?

Hope this helps.

 

[Suns Den]

As kevo said, this question appears to be addressing a reinforced concrete beam. The ASD/AISC is a steel manual. so there is some confusion, however the "beam tables" included in the steel manual are generic to beam analysis and can be used to get the forces out of a beam of any type. So if your analyzing a concrete beam for example: simply supported with a concentrated load at the center - then you could use the beam tables in the steel manual to get that the maximum moment is at the center and M=Pl/4. You can then design a concrete beam to carry this moment. Is your initial post asking for the beam tables?
over/under, balanced, doubly reinforced?

"over/under, balanced" are steel reinforcing (rebar) limits to a concrete beam. Over reinforced means that steel area is greater than the maximum allowed (no ductility), under reinforced means that the steel area is below the minimum requirement. "Doubly reinforced" means that you have compression and tension (or top and bottom) reinforcing steel in a concrete beam.

Concrete can be designed by the WSD (working stress method) which takes the same approach as the steel ASD or by the Ultimate Strength Method (the same appraoch as the LRFD). FYI, it is my experience that concrete is typically designed based on ultimate strength but the WSD is still in the books.

I don't immediately recognize the format of this equation. What value is it supposed to calculate?

Hope this helps.

I did start the topic for more input on the steel tables, I,W,S type frames and other important tables that may be required for the test specially the am portion. The beam tables - are you referring to the once with reaction/shear/moment/deflection kind of information on it.

As I was doing Reinforced Concrete I thought I may continue to post here.

I did find some formulas to analyze the different scenario of over/under, balanced, doubly reinforced given a rectangular or T beam with As. (rho d ~ d comparison) from a old concrete design book. Its been a while probably like 8-10 yrs I haven't had steel/RC so some of my questions may be haywire.

I saw that formula "F=(bd^2)/1200 " used in one of the problems, don't remember right on top of my head what it was for.

 

[kevo_55]

Sun,

It's no problem. It's just I was afraid that you were mixing to two!!

As for the formula, it may be a minimum reinforcement ratio but I'm not quite sure. I basically had to re-learn concrete from school when I took my exams. Going to the ACI318-02 was a slight change in beam design for me. I recommend that you take a look at your problem book and make sure that you're looking at problems/solutions from current codes.