Existing Structure - Re-model - When to meet updated Codes
Existing Structure - Re-model - When to meet updated Codes
(OP)
I recently received a project that involves a local grade school. The work involves:
1) Taking out and installing new windows
2) Adding (2) additional classrooms
3) Miscellaneous repair and replace items
The school has basically no lateral restraint system as it currently stands...literally, the walls are 98% windows with about a 12" return corner.
The Architect and School District are asking if we need to do seismic upgrades to the building since we are replacing windows and adding classrooms. I planned on designing the class rooms as stand alone systems and not touch the existing building. How far would I need to go if I did upgrades to the worst parts of the lateral system? There's at least one wing that has shear walls on (3) sides. The wings are long...probably 140-180ft long and about 30-40ft wide.
Would I need to do upgrades at all because we aren't changing any loads on the system as a whole? The building is wood framed with brick veneer.
1) Taking out and installing new windows
2) Adding (2) additional classrooms
3) Miscellaneous repair and replace items
The school has basically no lateral restraint system as it currently stands...literally, the walls are 98% windows with about a 12" return corner.
The Architect and School District are asking if we need to do seismic upgrades to the building since we are replacing windows and adding classrooms. I planned on designing the class rooms as stand alone systems and not touch the existing building. How far would I need to go if I did upgrades to the worst parts of the lateral system? There's at least one wing that has shear walls on (3) sides. The wings are long...probably 140-180ft long and about 30-40ft wide.
Would I need to do upgrades at all because we aren't changing any loads on the system as a whole? The building is wood framed with brick veneer.






RE: Existing Structure - Re-model - When to meet updated Codes
RE: Existing Structure - Re-model - When to meet updated Codes
RE: Existing Structure - Re-model - When to meet updated Codes
RE: Existing Structure - Re-model - When to meet updated Codes
My take on my understanding of the situation you describe is that you don't have to upgrade the building's lateral system but if you do you have to address the whole thing. Which is quite a shame, since, as you noted, any upgrade would be an improvement. Perhaps you could get the school administrators to ask the building officials for a waiver thus allowing you to partially improve it as funds allow? If that doesn't work bring it before the Parent-Teacher Association and they might be willing to apply political pressure as needed.
Take all of the above with a grain of salt.
RE: Existing Structure - Re-model - When to meet updated Codes
Be careful where you tread regarding the seismic retrofit idea. The original concept *may* have been designed to code. Maybe they used some tricks to make the open diaphragm work. Read up on the Existing Structures part of the code. Your small reno could turn into a huge cost if you do need to do the seismic repair and that may ruffle some feathers (or condemn the school). On the other hand, no one wants a school falling down in an earthquake.
To keep your butt covered, you should probably request a fee to do a structural observation for the lateral system and dig deeper. If you could get drawings, that would help a lot.
When I am working on a problem, I never think about beauty but when I have finished, if the solution is not beautiful, I know it is wrong.
-R. Buckminster Fuller
RE: Existing Structure - Re-model - When to meet updated Codes
I like the idea of talking with the building department.
RE: Existing Structure - Re-model - When to meet updated Codes
RE: Existing Structure - Re-model - When to meet updated Codes
RE: Existing Structure - Re-model - When to meet updated Codes
If you are using the IBC you will be in chapter 34. There are a few structural paragraphs in chapter 34 that relate to your problem. Some jurisdictions eliminate chapter 34 in favor of the IEBC.
I have heard of the cost requirements described by Ron, but I don't think I have ever seen them in either of these two codes (although I have seen work area referenced).
If you are in the IEBC, one more thing to note is that I believe both you and the architect need to be on the same page with your design approach. If the architect is the prescriptive compliance method or the work area compliance method you need to be using the same (unless the building official says otherwise).
I think you will find that if your new addition is structural separated from the existing school and you are not modifying any structural items in the school an upgrade may not be required.
RE: Existing Structure - Re-model - When to meet updated Codes
RE: Existing Structure - Re-model - When to meet updated Codes
I can't find anything that says that lateral upgrades are required for replacing windows. Maybe I'm missing something?
As far as the classification, there aren't any repairs/alterations/additions to any of the structural elements of the building. I will design the (2) new classrooms as stand-alone systems. That being said, the only part that I see as applicable is the "Voluntary Seismic Upgrades" section.