# AASHTO 5th ed 2010 Vs. AASHTO 4th ed. 2007



## hank89 (Feb 26, 2012)

Does anyone know if there are major differences between these two for the LATERAL portion of the AM EXAM??? I'll be taking buildings for the afternoon portion. I took the vertical exam in the fall passed and still have a copy of AASHTO 4th ed. Now they've changed all the standards for the april exam and i have spent a fortune on all of the other standards. I do not want to have to buy another bridge standard which I will never use after the exam.

Thank you!!!


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## McEngr (Feb 26, 2012)

Seismic design is pretty different. The mapping of spectral accelerations and how you come up with Csm appears to be different. I'm not a bridge guy, but the study texts that cover seismic design are not consistent between those two standards.


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## ipswitch (Feb 26, 2012)

I just mulled over the seisemic section the other day to help out the other poster a bit. It doesn't seem too arcane, but I haven't read it in depth yet.


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## hank89 (Feb 26, 2012)

On the vertical AM exam...I would say out of the 40 questions there were about 4-5 bridge questions I didn't have a clue how to work and I would say there were 4-5 building questions a bridge guy would strugle with.

On the vertical AM exam there were many analysis questions that both bridge and building engineers would have been exposed to in college. But wind and seismic are completely different when considering bridges and buildings.

Why should a building engineer have to spend time on seismic design for bridges which he will never use? I do not understand this at all. Bridge Engineers and Building Engineers are two entirely different profession (I know...I did bridges 8+ years ago-preLRFD). The only thing in common are anaylsis techniques and those were covered on the vert exam...

Thanks...end of complaining


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## hank89 (Feb 26, 2012)

McEngr said:


> Seismic design is pretty different. The mapping of spectral accelerations and how you come up with Csm appears to be different. I'm not a bridge guy, but the study texts that cover seismic design are not consistent between those two standards.


McEngr which study texts are you referring to. The serm? There's not much lateral design in the 5th edition....the bridge section is about 10 pages...Do you know if the SERM 6th edition is different than the 5th ed for bridge wind/seismic?


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## dakota_79 (Feb 26, 2012)

hank89 said:


> The serm? There's not much lateral design in the 5th edition....the bridge section is about 10 pages...Do you know if the SERM 6th edition is different than the 5th ed for bridge wind/seismic?


Can't offer a comparison as I only have SERM 6th ed. But in 6, the bridges chapter is 59 pages, and the lateral section is 56 pages (and fairly broad, though not too deep and not what I'm leaning on for lateral review). FWIW, I remember seeing a previous post stating the 6th ed was a significant improvement over the 5th in these areas.


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## dakota_79 (Feb 26, 2012)

Naturally, it was our guy McEngr who posted said topic:

http://engineerboards.com/index.php?showtopic=17606


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## hank89 (Feb 27, 2012)

thanks for the info guys


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## Hoven (Feb 29, 2012)

I am also a building guy taking the lateral for the second time with the old AASHTO Manual

McEng can you please clarify the differece between calculating the Csm. I have the SERM 6th edition and it looks like it calculates the value the same way as in the 2007 AASHTO (w/ 2008 interim revisions).

I am not as worried about the mapped spectral accelerations as those will always be given in the problem statement (probably for the benefit of those who don't know geography).

thanks for your help.


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## tws (Mar 14, 2012)

hmmm...thought I was okay, but now...??

http://engineerboards.com/index.php?showtopic=17921

I haven't bought SERM 6 yet, but sounds like it is a good AASHTO reference for AM Lateral. SERM 6 + 4th ed AASHTO okay for morning lateral? Can we get a consensus from any bridge people?

Thanks!!


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## McEngr (Mar 14, 2012)

The 2008 interim addendums show the difference in Csm. The original AASHTO 2007 doesn't calc the same.


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