The dangers of software and code changes 1

[Eng16080]

I use WoodWorks Sizer for sizing most wood members. I must have installed an update recently or inadvertently changed program settings because I just noticed the default code is set to ASCE 7-22 and not ASCE7-16 therefore using the snow load combo: D+0.7S rather than D+S. Fortunately this came to light while manually checking a beam calc. and noticing the end reactions were off.

I realize this is ultimately my error, but it makes me wonder how often errors like this occur, and if the code writers realize the potential problems caused by messing with these loads seemingly every other code cycle. I'm sure there are software users who wouldn't suspect any great harm in using the newest code in the analysis. (I'm not necessarily defending them.)

Sometimes I feel like it would be safer to write my own software for some of this stuff and just lock it to the codes I'm currently using (ASCE 7-16, etc.) and then use these same codes for the next 20 years or so (until I retire). Maybe it's not a perfect approach, but I doubt I'd ever be more incorrect than I was today due to the rather large difference between 0.7S and S.

I don't really have a question here, but wanted to mention today's screw up in the hopes that somebody else might avoid the same error. I always try to be careful but this one certainly caught me off guard.

 

[Eng16080]

And I remember what a pain it was for everyone in my old office to change their mindset for wind at the time.

Same here. I had conversations with other engineers at the time who weren't aware that the new higher wind loads were only to be used with the new load combinations. They thought the resulting wind demand on a structure was suddenly much higher. They'd say things like: "It's going to be harder to get this building to work with the new wind loads." Overall, it's just confusing for everyone.

Plus you lose (at least temporarily) an intuitive sense of what a reasonable wind load value is. It would be like if they changed the typically residential floor live load of 40 psf to something like 60 psf halfway through an engineer's career. For me, it would be difficult to unlearn "40 psf" and I'm sure I might make some mistakes as a result.

 

[Eng16080]

Be careful with the new snow in a few locations it is more than just a change to LRFD, the ground snow loads have also received a considerable boost. There was a structure magazine article covering it, https://www.structuremag.org/article/ground-snow-loads-for-asce-7-22/

Good call. I was aware of this from another thread here a few months ago. I'm sure it won't be for another 5-10 years anyway before my state adopts a building code which requires ASCE 7-22 or newer. I'll probably forget all of this by then.

 

[XR250]

Same here. I had conversations with other engineers at the time who weren't aware that the new higher wind loads were only to be used with the new load combinations. They thought the resulting wind demand on a structure was suddenly much higher. They'd say things like: "It's going to be harder to get this building to work with the new wind loads." Overall, it's just confusing for everyone.

Plus you lose (at least temporarily) an intuitive sense of what a reasonable wind load value is. It would be like if they changed the typically residential floor live load of 40 psf to something like 60 psf halfway through an engineer's career. For me, it would be difficult to unlearn "40 psf" and I'm sure I might make some mistakes as a result.

I agree. I think the push to make building design more structurally efficient and reliable probably does the opposite in some cases. I really think we should go back to ASD for everything. (coming from someone who still uses the Green Book).

 

[JoshPlumSE]

There is constant tinkering with codes. Some of them are essential for safety. Like when we added confinement requirements for concrete columns, or re-did the seismic weld criteria for steel moment frames.

Some are relatively minor. Where they adjust load factors, resistance factors, allowable stresses based on testing.

The ones that frustrate most of us are the ones that are merely intended to "modernize" the code.... Like switching from ASD level forces to ultimate level forces. Heck, ASD 9th edition was in 1989 and the industry didn't really switch over to LRFD until 2007 when the 13th edition started gaining steam. Maybe switching from fastest mile wind speeds to 3 second gusts. A lot of these changes are made because the engineering codes no longer match what the government and academic researchers are doing. If the USGS doesn't collect fastest mile wind speed data anymore, then the codes will eventually be changed. It might take 10 or 20 years, but that change will eventually happen. Ideally, it makes it's way into the code commentary and appendices for a couple of code cycles before it gets incorporated into the main body of the code. But, it's going to happen eventually.

Caveat: I sympathize with all of you dealing with code changes. However, I've been on the software side for the majority of my career. Therefore, I tell you unequivocally that code updates REALLY help sell software. So, while a sympathize with other engineers, my frustration is tempered by the fact that these code changes help my company's bottom line greatly.

 

[JoshPlumSE]

I should also mention that I attended code meetings (AISC mostly) twice a year for 10 years. And, I can attest that there is a lot of effort made to listen to everyday engineers. However, relatively few of them are involved in the code writing process. In general, I'd say that there are a few types of people that attend these meetings:

a) Academics who are eager to get funding for new research and like to see their research affect the codes. They're not bad guys. Though (IMO) a lot of them have very little concept of what regular engineers do from day to day.

b) Industry representatives. They represent manufacturers, trade groups, software companies and such. They are there to keep an eye out on any code changes can affect their company. Again, these aren't bad guys. They understand a lot about the industry niche(s) their companies occupy. They also tend to have a much better understanding of what engineers do. Many of them are former engineers and / or speak regularly with their engineering customers. This was the group I was in when I was there.

c1) "Real Engineers". I put this in quotes because I'd guess half of these engineers are more academic or business types. We're talking about the presidents and vice presidents of large engineering companies that no longer do much day to day engineering. They're no longer slogging through calculations and drawings on a day to day basis. That being said, they know EXACTLY what engineers do on a day to day basis. They've just moved past it. Think of them as Jack Welch type of guys. They went to school and got advanced degrees, then went into the private sector and used their academic credentials to climb the corporate ladder. They probably spent 5 or 10 years doing the day to day work that most engineers do. But, now they're 10 years removed from that. They peek their noses into it now and then. But, just as likely they're publishing journal papers or sponsoring research on pet projects of theirs.

c2) Same as item c1, but removing the quotes. These folds tend to own their own smaller companies. They may still be in responsible charge for every project that goes through their office. They are doing well, but they don't want to give up the day to day engineering because they LOVE what they do. They also care intensely about the profession which is why they spend so much time at these committee meetings.


I'd say that (a) and (b) each represent about 1/3 of the members of the code committees I saw. While c1 and c2 are equal components of the rest..... Meaning that about 2/3 of the code committees have a really good idea about what working structural engineers do and the struggles we have. However, only about 16% of them still do this type of work.

I don't think any one of these groups "dominate" the code committee meetings. In fact, I'd say it's a pretty congenial balance between the groups striving for shared goals. That being said, the Academics have the most time and energy to spend on the code provisions. They may have grad students that they can assign to do the work they volunteer for.