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ASD Steel Construction Manual...
15

ASD Steel Construction Manual...

ASD Steel Construction Manual...

(OP)
Anyone know where I can get a copy of the 9th edition ASD Steel Construction Manual.  It doesn't have to be an acutal book, a download would be fine.  Thanks.

RE: ASD Steel Construction Manual...

Check out AISC.com

RE: ASD Steel Construction Manual...

It's not available from AISC anymore.  Your best bet is to try eBay or some other second-hand book seller.  You might get lucky at a brick and mortar used book store, but it's not likely.  Expect to pay upwards of $120 for a used copy.

RE: ASD Steel Construction Manual...

That's unbelievable!  One hundred and twenty dollars for a steel manual that's 20 years old?  
I guess I'm not going to give my copy to my kids to color in.

RE: ASD Steel Construction Manual...

I have one at home that I used in college.  Can you believe they taught 9th edition ASD in 2005?!

RE: ASD Steel Construction Manual...

That there is one of my most prized items in my office. Long live ASD!

RE: ASD Steel Construction Manual...

If you are an AISC member, you can get just the 1989 specification from the AISC website in the "ePubs" section.

RE: ASD Steel Construction Manual...

Maybe one day the Yahoo's that promote LRFD will figure out that ASD is just fine and the logic actually makes sense.  As with FSS, my "red" book holds a prominent place on my bookshelf.

Hey FSS...give me a call!  I still owe ya a beer!

RE: ASD Steel Construction Manual...

The 13th Edition Manual provides ASD and LRFD design examples.  Is there something specific you are looking for from the antiquated spec or manual?

http://www.FerrellEngineering.com

RE: ASD Steel Construction Manual...

Quote:

ASD is just fine and the logic actually makes sense

What logic?  ASD treats dead, live, and wind loads as if they have equal levels of variation from the nominal value.  That doesn't seem very logical to me.

I'll agree that ASD still provides an adequate level of reliability for design.  History has proven that.  But let's not pretend like LRFD isn't superior.

RE: ASD Steel Construction Manual...

I have about 8 AISC manuals on my desk of all different colors.  I love them all.  They are my pets.  

But there's something so special about load factors...

And I think that if I got Ron enough beers (someday smile ) he'll come over to the dark side.

 

RE: ASD Steel Construction Manual...

Have you done an online search?  I bought a 1948 edition for around $10 from a online book store (abebooks I think).

RE: ASD Steel Construction Manual...

(OP)
I have looked online and the best I can find is ebay for about $120.

Is the ePubs section on the AISC website free for memebers?  

Thanks for all the replies.  

RE: ASD Steel Construction Manual...

Abusement-
You have a point, however, it all comes down to accurately determining loads. With 6 chapters of wind loading to go through now, my guess is 10 engineers will come up with 10 different loading scenarios, all yielding very similar results.
I was actually taught LRFD in school...when I got to work, I was worried knowing I'd have to learn ASD. That is, until I saw how straight forward it is. Now, It seems that AISC is almost backing away from LRFD a little bit and they have created a mess of a manual in the 13th edition which basically allows the use of ASD the same as it ever was with some minor differences.  

RE: ASD Steel Construction Manual...

For most steel ASD or LRFD its whichever you are most comfortable with.  The exception is composites beams, they are soooooo much easier with LRFD.  I like nice plastic rectangles instead of those pesky ASD stress triangles.

RE: ASD Steel Construction Manual...

green 9th was like vinyl.
grey LRFD was like laser disc
black 13th is like dvd


i love my 13th edition. i love the way AISC combined ASD and LRFD. i just with they had kept column tables for A36 wide flanges.

RE: ASD Steel Construction Manual...

Quote (graybeach):

I bought a 1948 edition for around $10 from a online book store (abebooks I think).

Yes, they must have made a million of the 5th edition.  You can find it for next to nothing.  The 9th edition is a different story, though, being that it is still used by many engineers.


Quote (Jambruins):

Is the ePubs section on the AISC website free for memebers?

Yes.  The 1989 specification can be found here.  http://www.aisc.org/WorkArea/showcontent.aspx?id=10292

RE: ASD Steel Construction Manual...

(OP)
Does the 1989 spec in the ePubs section have all the lookup tables?  Is it the whole book in pdf format?  Thanks.

RE: ASD Steel Construction Manual...

No, the whole book is the Manual.  The Specification is just the part that tells you how to calcualte your allowable stresses, things like that.  The Specification does not contain the lookup tables.

RE: ASD Steel Construction Manual...

JAE...I've been to the dark side in both steel and aluminum...still prefer ASD, but then, it's probably just because it was the way I first learned and got used to it.

Nothing wrong with LRFD, just that all my spreadsheets are ASD and I'm too lazy to create new ones.

RE: ASD Steel Construction Manual...

I was taught LRFD in school, then got in the real world and chose ASD.  

RE: ASD Steel Construction Manual...

Having learned in the 9th edition (still using) and reviewed the 13th, I realize that my issue is not with ASD per se.  It is the fact that LRFD introduced too much new stuff for the sake of saving a pound of steel, and I lost many of the formulas that I was so comfortable with, not even LRFD versions.  13th ed ASD is not the same as 9th ed.  

For crying out loud, we all factor our loads for concrete design.  We are all intelligent enough to do that.  LRFD in the 80's was merely the introduction of too much complexity, IMHO. AISC is not listening to those of us who need speed over steel savings.

RE: ASD Steel Construction Manual...

4
I started out as an ME so the idea behind ASD is much more logical in terms of "stress analysis"; however, I did take several steel design classes in my undergraduate and was taught LRFD. I do respect the point that dead, live, and wind are treated the same under ASD. From a mechanical engineering perspective I have gained a comfort (perhaps false) with knowing the stress levels with respect to the given code allowables, so for me I love ASD. In practice, I have mainly worked on the construction side with falsework and rigging so ASD has been the weapon of choice.

Perhaps my biggest issue is that LRFD is setup so every equation produces some load or moment capacity based on lets say a 0.9 resistance factor and some combination of 1.2 and 1.6 so it is not immediately apparent what stress levels you may be dealing with. Like I said, maybe I have developed a false comfort with the idea of some allowable stress, however, I feel the methodology to determine a "capacity value" goes too far and hides the true behavior. Tell me the LRFD moment capacity of W12 X 50 and I have many additionaly questions to ask you to determine what the load situation looks like. Tell me you have a W12 X 50 with 16,000 psi bending stress and I can tell you what else we can put on it to load it up!

I also agree with the above post that we have come to a point of diminishing returns. Is it worth saving the steel if you cannot look at a set of equations and "see through" the terms to fully understand the theory used to derive the equation. I fall back on Blodgetts "Design of Welded Structures" as a clear example of presenting a clear and simple methodology to solve everyday problems. It obviously is not based on the cutting edge theory , however, it is clear, concise, and provides basic methods using ASD to solve real word design problems.

Look at Appendix D in the Concrete Code for design of embedded anchors, is that any better than the basic equations given in the PCI 1979 design manual with the basic 45 DEG breakout cone? (Discussed numerous times on ENG-TIPS)

I understand that Universities need to complete research and people want progress, however, the fundamentals have not changed and in practice I feel we are sorely lacking the fundamentals to make good solid, well-rounded structural engineers rather than techincal "experts" who can save 5-lbs of steel on a simple span beam.

RE: ASD Steel Construction Manual...

LSPSCAT...nicely stated.

RE: ASD Steel Construction Manual...

I little of the AISC history on ASD v LRFD.  Research in the late 80's had shown that LRFD provided a more economical design.  However the saving where seen primarily in commercial design with relatively high dead loads.  Little savings are obtained in industrial design with high live loads. With the publication of the 1st Ed LRFD, AISC intended to phase out ASD.  Schools began teaching LRFD exclusively and new research data was established using ultimate forces and LRFD.  The AISC approach was that no new publications of ASD would created unless errata was necessary for unsafe applications of the ASD Manual.  All new research was applied to future publications of the LRFD Manuals.  Even with this ASD persisted as the primary manual for industrial design. Due to the confusion of fabricators over service v ultimate forces, commercial firms often designed using LRFD and provided service loads on the drawings to avoid unnecessary increases in fabrication estimates.  

Engineering firms also have a large investment in software and training of their engineering staff.  Without significant savings industrial firms were not motivated to covert th LRFD.  

After twenty years AISC began a change in philosophy. The primary goal should be the promotion of steel design over alternative materials.  A survey of the industries leading designers found that the primary concern with ASD was that the manual was antiquated with respect to the previous 20 years of research.  Thus the 13th Ed combined ASD/LRFD manual.  Note that the manual lends no preference to either code and provides parallel design examples.  

The 14th Ed Manual has been completed in a similar format and should be available later this year.    

http://www.FerrellEngineering.com

RE: ASD Steel Construction Manual...

Also note that the current Standard (Specification for Steel...) refers to ASCE for load combinations.     

http://www.FerrellEngineering.com

RE: ASD Steel Construction Manual...

Lets be clear - the new "ASD" - Allowable Strength Design - is not what was set forth in the 1989 Green Book "ASD" - Allowable Stress Design.

There is a substantial difference in the methodology and AISC has made this distinction. We now have three different animals.

Fundamentally I do not like the idea of an "allowable strength".

I am not questioning that significant research has been incorporated and that it may provide a more efficient design in commercial construction. I understand the merits, however, I am not convinced on the benefits.

RE: ASD Steel Construction Manual...

The Aluminum Association has had parallel ASD/LRFD design procedures for over 10 years.  I've done a few projects where the EOR dictated LRFD in the subsystem design.

One of my associates, graduated in 1997, treats his LRFD manual like we diehards treat our ASD manuals.  When I'm reviewing his work, I have to check things a bit closer than if he had used ASD, but overall it's a good exercise for me.

RE: ASD Steel Construction Manual...

LSPSCAT nailed it on the head.  There are currently 3 different methodologies.  

Unfortunately, I understand connectegr to say that the next edition doesn't address industry which has largely decided that steel has won the material battle.  ASD still is not taking off in the 13th edition because it doesn't address the REAL issue.  Therefore, 14th ed will be more of the same.  

I certainly can't recall a discussion or an article in Modern Steel Construction (by AISC) which has addressed the real heart of the argument of 9th ed vs. 10-13th ed, ease and speed vs. unnecessarily tedious calcs.  AISC ignores like minded engineers and presumes that we just want to stay behind the times. Insulting!



OK, time to get off the soap box.  Jambruins - I'm sorry if some of us hijacked your thread.

RE: ASD Steel Construction Manual...

"...Tell me the LRFD moment capacity of W12 X 50 and I have many additionaly questions to ask you to determine what the load situation looks like. Tell me you have a W12 X 50 with 16,000 psi bending stress and I can tell you what else we can put on it to load it up!  ..."
False comfort for sure.  With old timey ASD, you could have fb=16 ksi (from all DL) and compare that to Fb=24 ksi and get the idea that the situation is equivalent to fb=16 ksi (from all LL) vs Fb=24 ksi.

"I also agree with the above post that we have come to a point of diminishing returns. Is it worth saving the steel if you cannot look at a set of equations and "see through" the terms to fully understand the theory used to derive the equation."
I don't follow this logic.  If I look at 2005 Chapter F equations, I get a much better idea of physical behavior than what's apparent from the 1989 counterparts.  Someone in here going to claim to see warping and pure torsion in the Fb=12000Cb/[whatever] equation?  I think this is the single biggest positive leap that's been made from 89 to today.

RE: ASD Steel Construction Manual...

Quote (jsdpe25684):

There are currently 3 different methodologies.
I disagree.

Quote (LSPSCAT):

Lets be clear - the new "ASD" - Allowable Strength Design - is not what was set forth in the 1989 Green Book "ASD" - Allowable Stress Design.
Sure, but only because one document came out in 1989, and the other 16 years later.  If AISC hadn't abandoned ASD back in the '80s, we'd all be used to the "current" ASD as the natural progression of the green book.  How many threads are on this forum asking how to calculate something that is not addressed in the green book, that is addressed in later volumes?  The specification has developed to include more scenarios.  The fact that it has grown more complex is analagous to the observation that ASCE 7 has doubled in size the last five years.  It is not indicative of a third design philosophy.

RE: ASD Steel Construction Manual...

4
Letting my mind wander.

When I started working in the drawing office in 1951, there was only allowable stress. Analysis of statically indeterminate structures was generally by Slope Deflection or Moment Distribution methods and took only primary load paths into account. We didn't try to pretend that we could calculate with any great accuracy using a slide rule so we didn't skimp on material. Secondary and tertiary load paths provided redundancy.

Then "Plastic Design" came along, invented and pushed by some university types. A fixed ended beam could be allowed to go fully plastic at the ends and the middle before it would fail. Marvelous, but columns had to have greater moment capacity than the beams or the column would develop the plastic hinge first and fail as a column. It disappeared.

Along came computers that calculate stresses to thirteen decimal places from guesswork loads and use all of the available load paths. With them, came Ultimate Design so that resulting structures had been skinnied down to the borderline of failure. Now we have to deliberately add redundant girders to bridges and other structures.

I keep hearing that we save much steel over the old designs but I wonder how much money we actually save. If you reduce the weight a beam by 10%, you save only the 10% of mill cost and freight, the labor cost remains the same, and that is the largest part of the cost, by far.

To my way of thinking, structures live in a service load world and should be designed as such and tweaked to provide the additional load capacity for the possibility of extraordinary conditions. My body is designed for everyday conditions and I have some inoculations to help me fight extraordinary conditions. I do not want my body to be rebuilt to best fight the extraordinary instead of the everyday, I like it when it is equipped for the everyday.

Rant over, highjack done,carry on chaps.

Michael.
Timing has a lot to do with the outcome of a rain dance.

RE: ASD Steel Construction Manual...

Quote:

It is the fact that LRFD introduced too much new stuff for the sake of saving a pound of steel
Best I can tell, that is not a fact...and that's a fact LOL.  New stuff has been added to fill in holes.  There are dozens of design checks that are missing from the 89 ASC Manual that are in the 13th Ed.  Until someone invents a way to make something bigger on the inside than it is on the outside, that's going to require a bigger and more complex book.

Here are a couple for you guys who still have your fingernails digging into your green book as AISC maliciously drags it away: How do you calc the allowable axial load for an I-shaped column with different flange thicknesses?  Second, how do you check a W-shape with cap channel for lateral-torsional buckling?  If I was a betting man, I'd bet good money that all of you are checking these with ASD 89 equations that don't apply to those situations.  Further, nobody can tell from looking at those equations that they don't apply without digging into Salmon and Johnson or some other book.

Quote:

...and I lost many of the formulas that I was so comfortable with, not even LRFD versions.
Examples?  I think there is only one obscure design check that existed in 89 that doesn't exist now--could be wrong about that, though.  Of course the equations look different because different models are used.  Take unbraced beams for example.  Look in Salmon and Johnson, far enough back that they cover both ASD89 and AISC86 or 93.  The Fb vs Lb curve for LTB is a real mess for ASD89.  It's far, far cleaner and more logical using the modern formulation.

Quote:

AISC is not listening to those of us who need speed over steel savings.
I've never understood this objection.  I used ASD89 for 3 years then LRFD since 98.  I've designed many projects with very tight early release schedules with LRFD and it doesn't cause problems because I very rarely crank through sizeable equations from the Spec.  It's either done with a program or a table.  If someone's still doing lots of manual calcs in 2010, then IMO that's an issue with how the engineer chooses to do the calcs.  If the issue is that the mean ole' 13th Ed. has a design check (that applies) that wasn't in the 89 Spec., then no sympathy on needing to check it, right?   

RE: ASD Steel Construction Manual...

I disagree with LSPSCAT.  In ASD you are dealing with stresses well below yield.  In LRFD you are dealing with a stresses at Yield.  To get similar performance in the first case you ratio down the yield, in the 2nd you ratio up the loads.  It gets you to the same place in almost the same manner.  I happen to think LRFD is better because it deals with actual performance (plastic) at high loads, not elastic performance which isn't what applies when loads approach failure.  Of course I also learned LRFD in school, and ASD later on.  

It comes down to whatever you are more comfortable with.

RE: ASD Steel Construction Manual...

Quote:

I have one at home that I used in college.  Can you believe they taught 9th edition ASD in 2005?!

No, I cannot, since I was taught LRFD in 95/96 at my school.

When I went to the PE review class, the teacher was appalled by the size of the LRFD manual.  The next week, I brought in the connections book that he did not even realize existed.  When he saw that, he vowed he would stop teaching the review course when the balance tipped to more students knowing LRFD.

When I took the PE, I took both ASD and LRFD books.  That worked out well, since there was one question easier to answer for each method.

RE: ASD Steel Construction Manual...

Those of us who already had work experience before LRFD arrived, had to try to learn this new method while still producing a week's worth of work each week. It was not enough for one person to switch, the checkers and reviewers also had to make the change.

It was much easier to continue with a system of design that was not broken. Making the change was similar to changing direction in an ocean liner, it takes time and distance, and it takes guts to switch from a proven system to an unproven, counter intuitive, system invented by the pointy heads at the universities.

Michael.
Timing has a lot to do with the outcome of a rain dance.

RE: ASD Steel Construction Manual...

Paddington's rant above makes a lot of sense to me.
I never could understand how engineers or university types could honestly believe that they have refined something down to the knats ass.
Mike is right, the loads are mostly guess work. I have worked on Super heavy industrial projects where, as the structural engineers, we had little or no loading information from the mechanical vendors yet we were constantly pressed to issue foundation loads to the foundation engineers. We literally had to come up with equipment loads on our own. Here is what happens:
Structural guy is SUPER conservative on estimating weights in his model or calc's.
The guy responsible for issuing "not-to-exceed" loads for the foundation guys factors the loads up to add some cushion in case things change (like they always do) and to be safe.
Foundation engineers receive the loads and again factor for both design and to be sure they are safe.

In the end the loads are almost entirely "guesstimated" and we actually believe we saved steel or concrete? No, we worked hard to save our ass and the clients power plant from collapsing for the sake off getting the plant online quick.

I understand that since almost all of my work has been in industrial settings, it can be a lot different in commercial construction.
In industrial, usually the structurals are the last guys to get info and the first that have to be done.  

RE: ASD Steel Construction Manual...

Several years ago I attended an AISC seminar to introduce the AISC 13th edition.  During this seminar they drew a business card and offered the winner their selection of an AISC manual.  I requested the 9th edition ASD.  I could tell he wasn't very happy, but I did receive my 9th edition shortly thereafter.

RE: ASD Steel Construction Manual...

ASD vs. LRFD is so tiring don't you think?


I was educated with ASD - used it for many years in practice.  Then LRFD came out.  I managed to learn it very easily (not an ocean liner changing direction at all).

It didn't take me but a few weeks to get into it and understand how to use it.  And I'm no super-exceptional engineer.   I just don't buy all this talk about how difficult it is to learn or use LRFD.

I'm amazed at the reluctance of engineers to learn new things once they get into practice.  I once worked with an engineer who used 1950 era ACI codes (this in the 1980's).  We used to chuckle about how he was an old stick-in-the-mud.

I can understand that you might just "like" ASD more and use it.  I have no problem with that.   But the 9th edition of ASD has changed to the 13th edition.  At some point you have to use the current version under legally adopted codes.
   

RE: ASD Steel Construction Manual...

JAE, I was referring to a large company, one large enough to have a couple of nukes and a couple of large fossil power plants in design and construction at the same time, when I spoke of turning an ocean liner. When the liner turns, everybody on it turns with it. With the company, the company isn't turned until almost everyone in the company is turned.

Michael.
Timing has a lot to do with the outcome of a rain dance.

RE: ASD Steel Construction Manual...

Michael - understand, thanks.

RE: ASD Steel Construction Manual...

Like some of you others, I'm moving slowly into LRFD, kicking and screaming.  But I don't think that totally blaming pointy headed academics is fair.  The way I understand it, LRFD was developed to align steel design with the limit based designs used in concrete (and available in CMU).  That way, when a building has a steel frame supported on a concrete grade beam or columns you can use the same factored loads. And also, the probability of unlikely load combinations can be weighted, like LL plus full wind.
Now this logic falls apart when the soil allowables are allowable stress values or the CMU is done b allowable stress.  But that's the approach that the powers that be are taking.

RE: ASD Steel Construction Manual...

Careful Jed, there is a movement afoot to get Geotechs to start giving ultimate values.

RE: ASD Steel Construction Manual...

Maybe we should have a stamp on our driver's licenses indicating ASD or LRFD across our face.

(feeble attempt to insert humor into this thread)

 

RE: ASD Steel Construction Manual...

JAE - I think the grey hair would give it away first!

No offense to anyone... just kidding around!

RE: ASD Steel Construction Manual...

This is indirectly related. At my first job I had National Service deferments and given one day per week to go to the technical college, until I took my Ordinary National Certificate. We tackled statically indeterminate structures during the third year. When I learned Moment Distribution, I used it at work. When we learned Slope Deflection, I used it at work. When we learned one of the calculus methods, I used it at work. Until the boss told me to stick to Moment Distribution and Slope Deflection because nobody else could remember how to check my work when I used something else.

Michael.
Timing has a lot to do with the outcome of a rain dance.

RE: ASD Steel Construction Manual...

there is a pdf of aisc 9th edition.. you just have to be "resourceful".. if you know what i mean..  =)

RE: ASD Steel Construction Manual...

Quote:

I've never understood this objection.  I used ASD89 for 3 years then LRFD since 98.  I've designed many projects with very tight early release schedules with LRFD and it doesn't cause problems because I very rarely crank through sizeable equations from the Spec.  It's either done with a program or a table.  If someone's still doing lots of manual calcs in 2010, then IMO that's an issue with how the engineer chooses to do the calcs.  If the issue is that the mean ole' 13th Ed. has a design check (that applies) that wasn't in the 89 Spec., then no sympathy on needing to check it, right?   

+1

I've never understood people who complain about the code being complicated.  Are you seriously crunching through all these numbers by hand?  If so, then me, LRFD, and my computer programs can run circles around you, ASD, and your pen and pad when comes to cranking out design. For me, the vast majority of the time, the difference between using the two methodologies is a simple click on the mouse.

Also, as it was previously stated, what about the major formulations has changed?  The majority of the changes I have seen have been to account for using forces instead stresses (i.e. simple unit conversions).

I don't get the argument for it being desirable to look at stresses.  You can tell me a beam is stressed to 25 ksi, but that doesn't mean anything to me unless I know the critical stress, which will vary from beam to beam depending on bracing and compactness.  The real telling thing to look at is the stress ratio (i.e. applied load/allowable load).  IMO, this is the best way to quantify where you are with regards to design.

RE: ASD Steel Construction Manual...

abusementpark, don't take this the wrong way, I know from your other posts that you know what you are doing, I just want to use your last paragraph to explain something.

"I don't get the argument for it being desirable to look at stresses.  You can tell me a beam is stressed to 25 ksi, but that doesn't mean anything to me unless I know the critical stress, which will vary from beam to beam depending on bracing and compactness.  The real telling thing to look at is the stress ratio (i.e. applied load/allowable load).  IMO, this is the best way to quantify where you are with regards to design."

For someone like me who wasn't raised on the computer, this looks as though you are using the computer as a black box. I like to see, in my mind, the loads flowing down the load paths, I like to know the stresses, but then I think of critical loads, not of critical stresses, even though they are expressed as critical stresses; the strength of the  material of a member doesn't change because a member is slender. If I know what is going on, I can allow local stresses to exceed the "critical stress" as long as it is not in a location that matters. It seems so sterile to just check that the stress ratios are <1.

As I said, I know you are not a black box engineer, but your paragraph gave me a chance to say something that has bothered me for years.

Michael.
Timing has a lot to do with the outcome of a rain dance.

RE: ASD Steel Construction Manual...

Well said Paddingtongreen.  I see calc packages that are 3"-4" thick and not a single hand calc anywhere.  Just page after page of enercalc/RISA/you name it software.

RE: ASD Steel Construction Manual...

Taking designs from a black box = horrendously bad practice.

Using a program to do the number crunching after one has understood and agreed with what it's doing, and scrutinize results = more or less essential design practice now.

RE: ASD Steel Construction Manual...

(OP)
What software programs are you guys using? I would like to get an idea of which one to use or stay away from.  Thanks.  

RE: ASD Steel Construction Manual...

Sorry for getting the ball rolling on this hot topic! My inital argument was never that LRFD was too complicated or too hard to learn. I was educated as an ME and I find ASD more friendly towards heavy industrial/construction design...where it can be worked with the various ASME codes. As an ME we also tend to work more with basic stress analysis with principal stresses and von Mises criteria. AISC steel design has "codified" these design checks.

When it comes to concrete, you are right, I never learned another method so LRFD it was. Likewise when initially learning steel design I was taught LRFD and have used it in practice without issue.

I think the other main argument that takes place is simplification. Some of the arguments above state "ASD 1989 did not incorporate various design checks"...you are absolutely right..it was left to the engineers discretion to verify and check the design.

To tie in with Paddington's rant above this becomes the fundamental question. If all this is a matter of code and software..then structural engineering for basic commerical construction will continue to be degraded. I have found myself saying "...this must be in the code somewhere..." Sometimes I have to stop myself and get back to reality and realize that at one time we could live with less codified design checks and do some real engineering.


 

RE: ASD Steel Construction Manual...

I agree with paddington, as well. I'm a new engineer and was taught LRFD in school. My dad is a PE, so he actually taught me ASD89. As I'm comfortable with both now, I don't really have a preference. Most new engineers I went to school with rely entirely too much on software to run their calcs. At my old gig we had a green one design a moment connection that physically wasn't possible because he just turned around the computer read-outs. Terrible practice. As for myself, I run everything by hand in some way or another. It definitely gives you a better understanding of what's actually happening within a structure. I guess I'm lucky in the regard that my dad initially taught me that way, so now it's reflected in my work. (SIDE NOTE: All of the Senior PE's I work with love that I do most calcs by hand. Maybe because it's much easier to check.)

RE: ASD Steel Construction Manual...

Quote:

I think the other main argument that takes place is simplification. Some of the arguments above state "ASD 1989 did not incorporate various design checks"...you are absolutely right..it was left to the engineers discretion to verify and check the design.
The design is still left to your discretion but now you have "correct" equations to use whereas you previously did not for many design checks.  The creation of LRFD or development of new equations has not taken the design away from engineers.  It has taken it away if one would prefer to just cook up untested methods for a larger chunk of his work.  We have to do this at times, but the fewer times the better, right?

With ASD89, the engineer would almost inevitably do many checks incorrectly due to lack of guidance.  Just as a simple example, say a guy was checking an I-shape with different flanges for axial and/or for flexure.  He'd use the basic KL/r approach for Fa, which is incorrect (as most know now and far fewer knew in 89). For Fb, he'd use Fb=170000Cb/(L/rt)^2 or 12000Cb/(L*d/Af), both of which are incorrect.  

"Incorrect" meaning that the underlying formulations are not for the type of member being considered.  The engineer had no choice but to misuse (a lot of the ASD89 fans want to say that people misuse equations more nowadays...) these equations for lack of better guidance.  There are "correct" checks in the 13th Ed. Spec. for those cases.

RE: ASD Steel Construction Manual...

Quote:

(SIDE NOTE: All of the Senior PE's I work with love that I do most calcs by hand. Maybe because it's much easier to check.)
In my experience, senior PEs and SEs do more manual calcs because their time is too valuable to sit there operating programs for days or weeks on end (and therefore, it's not worth it to learn the programs in detail).  They'd do quick and simple stuff manually and have the junior guys crank for days or weeks with the programs.  They'd never approve of the junior guys trying to design dozens of composite beams on their jobs manually, for example.  The senior guy might use a Manual table for a composite beam or two at random, though.

After all, who do you think approved the purchase of the programs?  The senior engineers.

RE: ASD Steel Construction Manual...

I must be the odd dinosaur, I loved the computer as a tool from the beginning, working off mainframes until the PCs came along. Mostly, we used STAAD on the PCs.

Michael.
Timing has a lot to do with the outcome of a rain dance.

RE: ASD Steel Construction Manual...

4
I'm with paddington on this one.  We aren't better engineers because our computer prints results out to ten decimal places, when we don't really seem to have a feel for how the structure acts or reacts to various loads.  And, we sure aren't producing better structures or products, because of all our elaborate calcs. and methods, but it's all a hell of a lot more complicated.  And, that complication has become a self perpetuating end in itself, and the bane of our existence.

We know more about structures and materials than we ever have, in the history of mankind.  We have more sophisticated analysis tools and methods and manufacturing and construction methods than we have ever had.  I'm all for learning from experience, there is no doubt in my mind that what we have learned from recent earthquakes and hurricanes should be includes in our design codes for human safety and building survival reasons.  But, this might be done in a 20-30 page addendum, while my $150 copy of THE CODE starts to show some ware, from use, and I actually learn it.  And, even though the testing shows this to be true, no one in his right mind is going show a different fastener schedule for ever 2 sq.ft. area of roof as you move away from the corner, although it is interesting knowledge to keep in mind for special situations.  I tend to prefer ASD because that's what I first learned and have used the most.  But, as paddington suggested, I've designed closer to yield for years, as long as instability or serviceability didn't control.  I generally agree with the philosophy of LRFD, but this old dog is having trouble learning all the new tricks.  They have to make it much more user friendly, instead of so number manipulation intensive.

We are turning this whole business into some sort of a complicated cookbook approach, where any fool must be able to do it, if they only follow the complicated recipe, tooo theee letttter, never mind having any intuition about how things actually work any longer; that's not necessary, we've codified that too.  We can just not codify everything and every condition.  So, here's the recipe: it's for lemon flavored yellow cupcakes with poppy seeds, and it calls for 1200/3600 of a cup of poppy seeds, but I only have 1157/3600 cups of said seeds; oh crap, I can't make cup cakes today, the recipe doesn't tell me what to do under these conditions.  Well, we get a bunch of committees together, one for flour, another for yellow cake flour, one for lemon flavoring, and the all important one, for poppy seeds.  After years of testing and bickering we settle on 1159/3600 cups as being O.K.  Finally, we republish the 1200 page cookbook to correct that one recipe, and the publisher is real happy with the new edition, only $69.99 plus shipping, but no one can taste the difference.

I'm not calling for a full blown revolt or uprising, but something close to that, slightly tamer.  For starters, we should just quit buying every damn new edition of all of the codes and all of the new computer programs.  We pay a premium for all that crap and all of the new bells and whistles really don't improve our lives or give us better answers, results or designs or really make any of us better engineers.  This just keeps enriching the producers of this more and more complicated crap, in effect encouraging them to continue.  And each time, we have to stop production and relearn to use this new fangled system or code.

Code writing and publishing and the research surrounding it should not be an end in itself.  This has become a large industry unto itself which enslaves us to learning the new version, formulas or format and doesn't make us better engineers, designing better products.  This is the tail waging the dog, and it should stop.  We should leave them sitting with a million unsold copies of the latest, and really learn to use and understand the copy we already have.  The testing and research is wonderful new knowledge, worth having in my arsenal.  I used to get that from keeping abreast of many technical journals.  And, I would even use it when it helped me on a design or with an analysis.

 

RE: ASD Steel Construction Manual...

I would argue that computer programs give me a BETTER feel for the structure, the load paths, and the effects of my design decisions.

With my program, I can quickly alter various parameters, loads, member sizes, etc. and see INSTANTLY the effect on deflections, moments, etc.  I also can see the deflected shape of the structure instantly.

Do some mis-use programs and overly trust the results without checking?  Yes.  Do some not carefully develop input procedures and take the time to understand the program variables?  Yes.  

But good engineers don't follow those poor practices.

And the old way (by hand) couldn't offer you the feel of the design like todays programs...if you think you do have a better feel for it...just because you are using graphite and paper....you are fooling yourself.  

I used to do them by hand (late 1970's)...no thanks.  

Programs have freed us from tedious math and allowed us to become better designers in my opinion.



 

RE: ASD Steel Construction Manual...

As another old-timer, this thread hits too close to home.  For 2010 I put my 8th edition with my reference books and the 13th edition is now on my desk.  I am trying to use LRFD every day - but sometimes I fail.


My name is Gary and I used ASD.


Part of what I see as the bigger problem is the complexity of the Codes.  I used to joke that bridge engineers had to do more statistical analysis than structural analysis (although I only did bridge design in a classroom).  But now with 45 degree winds, reduced winds with torsional moments, 4-directions of seismic loading, 3-D models, etc., you find yourself ending up with way too many load cases.

Throw in Direct Analysis Method and my current industrial 3-story process/transfer building has 119 load cases.  When I questioned the software rep as to the time it takes to analyze this structure - he said "manually eliminate the load cases that do not govern".  Easier said than done.  There is no intuitive way to know exactly how the interactions affect different elements.

I can easily see becoming one of those black-box engineers.

gjc
 

RE: ASD Steel Construction Manual...

It didn't take me very long as a practicing structural engineer to realize two things:
1) engineering is not about calculating precisely the nuances of inaccurate guesstimates.  And,
2) a sharper pencil still won't make a weak structure stronger.

I frequently make presentation to groups of SE's on simplifying design.  The basic premise is that excessive complication in the beginning of any design is likely to result in a more expensive, more complicated, less robust design.

It is not ASD or LRFD which makes the design complicated or difficult, it is all the things leading up to the first computation, and the degree to which every component is optimized.  Sometimes more material costs less, and getting to a design which uses more material often takes less time and results in fewer errors, which saves even more money at every stage of design and construction.

RE: ASD Steel Construction Manual...

TXStructural and dhengr:

Here, here!  But in the next edition, I hear that you'll only need 1154/3600 cup of seeds. I can't wait!

RE: ASD Steel Construction Manual...

Anyone shying away from computer programs at this juncture is doing a great disservice to themselves and ultimately their company.  For the reasons that were excellently stated by JAE, the computer programs are better at giving you a feel for the load path.  Also, there are many simple checks one can do to verify if the input is correct:  Do my reactions satisfy equilibrium?  Are my moment and shear diagrams as expected?  How does the deflected shape look? Is there any unwanted torsion getting into some members?  Do the results make sense?.....etc.

I understand that there are a lot of engineers who may abuse a computer program and never fully understand what it is doing.  However, there are many of us who know to properly harness the great power of these computational tools and use them to our advantage. It is especially helpful if you have an educational background in the modern methods of structural analysis. Your faith in any computer program has to be tempered with keen sense of where things can stray from reality and where errors can be made.

Maybe some people are emotionally tied to the nostalgia associated with hand calculations. Don't get me wrong, hand calcs still have a vital role in what we do and should still be considered on a case by case basis. A lot of special connections require hand calculations.  However, for the vast majority of steel structures of any significant size, doing the main frame analysis in the computer is the way to go.  IMO, one the biggest advantages of doing a computer model of a steel structure is the method of convenient bookkeeping. Everything is one place.  Changes in the framing are easy implement late in the game. No need to follow a messy paper trail.  It is easy to look at your reaction envelope for the purposes of foundation design. Some programs even have the capability to automatically calculate live load reductions for each individual member!

Also, if some of you think that AISC is getting carried away with code complexity.  Take a look at the AASHTO LRFD manual.  It makes the AISC manual look like a pamplet.

RE: ASD Steel Construction Manual...

Quote:

It is not ASD or LRFD which makes the design complicated or difficult, it is all the things leading up to the first computation, and the degree to which every component is optimized.  Sometimes more material costs less, and getting to a design which uses more material often takes less time and results in fewer errors, which saves even more money at every stage of design and construction.

I've seen drawings where it is obvious that the engineer just used whatever "optimum" beam the computer spit out for each individual member and there are 25 different w-shape beam sizes on the job.  That's certainly not something for which I would advocate.

RE: ASD Steel Construction Manual...

Quote:

Some programs even have the capability to automatically calculate live load reductions for each individual member!
This brings up a question that I've had for a while.  The thread is hopelessly off course now, so I'll indulge in a further tangent LOL.  

I've always used frame analysis programs to do the lateral design and design beams somewhat individually using smaller programs.  I've not used whole system design programs like the Ram System enough to know the nitty gritty details.

Consider a model of a typical steel-framed floor with a few moment frames as the LFRS.  I'm not sure I even know the exactly correct LL reduction to use in such a model.  (I know what I do and it's a slight simplification that I think is OK.  EJ.)  If one was going after the "exact correct" answer, what influence area should be used to determine the reduced LL for gravity beams, gravity columns, lateral beams, and lateral columns?  This would seem like an easy question, but it's not IMO.  Global P-Delta effects should be for LL over the entire floor area, and these go into the indivdual member moments.  However, an individual moment frame beam would seem to need a larger LL for its KLL*At, but I'm not sure that's even exactly correct.  Same goes for a moment frame column.

After all that is the question.  What does Ram Steel and other similar programs do with this kind of issue?  Does it leave the individual element reduced LLs on there and then apply some upward corrective forces as have been proposed in some papers over the years?  If someone has a document describing the process used in the programs, I'd be interested to read it.

RE: ASD Steel Construction Manual...

Abusementpark & JAE:
I agree with you completely, computers and software are indispensable to our work today.  There is no doubt that we can study many different alternatives today than we ever could with a slide rule or hand held calculator.  For a fair share of our work we could not do without them today.  I actually taught a couple of courses in computers and structures, and did a fair amount of programming for consulting firms and industry in the mid to late 60's, while in grad school.  But, I am beginning to wonder if the latest codes or latest computer programs, are really improving our designs or making us better engineers.  These new versions are coming much to fast for me, and are more and more difficult to keep up with, and still get some productive work done.

I am asking, in the case of the next edition of the codes or the latest version of software, whether we are really just getting a few new bells and whistles which don't improve our designs and make use better engineers, or are we just enriching the sellers of this stuff, and frustrating ourselves in the process.  On both accounts, I submit, that we could slow down quite a bit and really learn to use what we have.  Our designs wouldn't hurt from that, we already have more computing ability than most of us know what to do with.  And, there are a bunch of people who probably shouldn't have access to this computing machinery, because they pretend that this makes them an engineer.  In fact this can be dangerous to others.
 

RE: ASD Steel Construction Manual...

dhengr -

Quote:

These new versions are coming much to fast for me
Probably true for everyone

Quote:

or are we just enriching the sellers of this stuff
we are enriching someone that's for sure

Quote:

I submit, that we could slow down quite a bit and really learn to use what we have
I think the momentum is too strong.  We might start some sort of mass campaign - get signatures, but I'm not too optimistic.

Quote:

there are a bunch of people who probably shouldn't have access to this computing machinery
But how would you be able to police something like this?

Quote:

this can be dangerous to others.
Mentor the engineers around you - both young and old.  

I've also thought about developing a "Code of Standard Practice" for using software in engineering.  Might be interesting.  And you might need a different code for different disciplines.

 

RE: ASD Steel Construction Manual...

JAE:
I wasn't really suggesting a signature campaign, all we have to do is quite buying that stuff when it doesn't really benefit us or our practice.  Each one of us doing that is worth much more than a bunch of signatures.  Between the bunch of us, if we bought only a few copies and critiqued them right here we would discover that they really offer nothing new or better, just a complicated new reformulation.  Then talk to your legislators, and building officials, at the state, county and city levels, wherever the adoption decision is made.  Their stock in trade is nit-picking on minor code details, and yet, the ones that I have talked to are almost as overwhelmed and frustrated as we are.  They can't keep up with it either, and still get any work done.  If we explained our position, and reasoning, to them, they might decide the new edition isn't worth adoption, in which case we wouldn't need to buy it.  We do probably have to show them that the new version offers no improvements in safety or economy, because that is not normally what they do, without some guidance from practitioners.

The momentum is so strong because the building code writers and computer program writers have become much too comfortable selling us bells and whistles that don't really improve our operation.  In some respects this is just another layer in the economy, which gets its pound of flesh, while not really contributing much improvement to the process or the finished product.  In fact, we see right in this thread that they complicate it.  Again, I am not suggesting we don't need building codes or computers and programs to do our work.  We just don't need the two intervening editions in what could be a ten or twelve year cycle, with a few addendums if the change is important enough.  SO, just quit buying the new versions, you are just encouraging them.

By now, you certainly must be aware that I am a strong advocate of mentoring.  And, when the young guys come into your office saying "they gave me the newest version free," a slick promotional gimmick, and that's how I learned to do it.  You may want to do some mentoring by splainin that we use the version on generation older so you'll have to do some slummin if you want to work here.  But, we still feel we turn our a darn good finished product, which is specs. and plans that can actually be built with min. confusion and with few RFI's.  Your 4" stack of computer output is not the end result, although it has become a very complicated and at times confusssing end unto itself.

RE: ASD Steel Construction Manual...

dhengr - nice thoughts.

But when your local jursidiction makes is LAW that they adopt building code X that refers to the latest ASCE 7, etc. what's a girl to do?

 

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