Structure Mag......Code Article 15

"Experienced engineers (5 to 40+ years) produced design wind forces that varied from 3.9 kips to 24.2 kips with a standard deviation of 42% in the results."

This agrees with what I have been figuring for some time now based on seeing other engineers work. I know I have unintentially missed things as well. All the west coast engineers seem to be currently having a hard time adjusting to ASCE wind, but seismic is even worse to me-especially getting all the special detailing right.

"Why have we as practicing engineers allowed the codes to become so complex? I propose the single biggest answer is apathy"

I agree with this one too, and apathy seems to fit our fees as well. But I am also guilty on the code part because I have never been to a committee meeting on anything and argued for simplification. A good one would be, why now does it have to take 4 hours to design a couple of anchor bolts by hand?

http://www.structuremag.org/Archives/2007-12/D-Editorial-Nuttal-Dec07.pdf

 

[TimmyH76]

I understand that all the "theory people" want to do this research and write all these codes, but honestly.....has the wind blown any stronger or the snow got any heavier in the last 50 years......the codes have to come back to reality!!

 

[BRGENG]

3 SE’s with a combined 80 years experience form three different firms all came up with the same answers. I will trust our math and results. We develop software together to share between our firms, it saves a fortune and you know how the software works and how to adapt it if necessary. Look at the updates Enercalc has released in the past and you will see why you should never trust third party software unless you can repeat the answers with hand calc’s. Years ago we noticed that Enercalc was applying the old 1/3 increase to masonry twice. How many masonry buildings were designed with a factor of 1.7689 instead of 1.33? Did you go back and change your design after the fact? Different topic for a different post, just watch out because Enercalc just redid everything.

As to where you can get anchor bolts deeper then the frost depth. Braced frames along the hurricane costs of the southwest. Many geotech only have a frost depth of 12” or 18”. A project we did in Myrtle Beach, SC, national proto type for a major pharmacy chain. They use slab on grade, steel frames with a braced bay for lateral forces. Combine the hurricane wind loads on the braced frames and you can easily get anchor bolt lengths greater then frost depth.

 

[271828]

BRGENG, I agree totally about manually verifying results of software. People don't do this often enough in my experience. There will be another major failure at some point due to mis-use of a program.

As for the example of BFs along the southeast coastline, that's too non-specific to be a good argument against App. D, in my opinion. Do you have a specific uplift force and required anchor rod embedment that you've found unreasonable compared to pre-App. D requirements?

LOL, I haven't studied App. D enough to know, but it sounds like the concrete equivalent to the AISC stability bracing stuff: According to the AISC stability bracing provisions, all metal building rigid frames should've collapsed by now!

 

[DarthSoilsGuy]

another good code rant concerning the other half of the code complexity nightmare: update frequency

thread507-203057

 

[271828]

vincentpa and/or BRGENG, do you have a specific ACI App. D unreasonable result?

 

[JadeRabbit]

In some cases, the codes make things a bit easier.

I like the appendix for Strut and Tie in ACI.

The real Question.
Who said that we have to adpot the new codes.
In Chicago they've been using ACI 318-83 through all the
new codes. Maybe instead of fighting the code writers.
We just convince our local politicians to not adopt the newer codes. (Easier than go to a committee meeting if you ask me)

 

[BRGENG]

Most local jurisdictions will adopt the most recent code because they fear the possible legal ramifications if they do not. They think that if a building fails and they require an alder code that a lawyer could demonstrate that the most recent code would have prevented the collapse.

Personally I don’t agree with this at all, in many rural areas the elected officials deciding the code have no idea what they are doing.

Here is a quick question to ask yourself. If you are designing a building in an area that dose not have a building code, what building code do you use? Would it be the 93 BOCA or maybe the 97 UBC or do you use the most recent recognize code the 2006 IBC? I always chose to use the latest code, currently the 2006 IBC unless the State the project is in has a different code adopted. This is also why local officials will almost always adopt the latest (but not greatest) code.