what invokes a remodel analysis

[garrettcoonrod]

Does a change of occupancy alone require a building to be upgraded completely to the new code requirements? I have a building that is going from residential to commercial. I can see that the floor live load will need to be increased but what about shear walls. Do they all have to be brought into existing compliance as well? To replace all of the mud sill washers seems like the biggest pain at this point. Not to mention that the existing anchor bolt spacing surely won't meet the calcs. once I complete them.

I have another commercial building where they moved a door over so there is technically the same length of shear wall. I made them bring that wall into compliance with new hold downs and the like but wish I could give folks a break sometimes if the code would allow.

I should mention that I am in California.

Thanks,
Garrett

 

[msquared48]

I know a lot of Mr. Nice Guys out there that have lost their shirts trying to save their clients money. Don't join their club. If the client can't pay the price of a remodel, then he should consider a new structure.

Mike McCann
MMC Engineering

 

[garrettcoonrod]

Thanks Mike,

That doesn't give me any answer to the question. How does the code treat remodels? Does an occupancy change mean the entire structure be brought to existing standards? The building in question is a single story built in 1995 so it is not a substandard or high risk structure at all. I have assumed that if a shear wall is manipulated in any way then that line of shear must be updated. How do other engineers treat remodels?

Thanks,
Garrett

 

[msquared48]

garrettcoonrod - sorry, I didn't mean to be blunt in muy comment, but I have found this to be true. Just keep in mind that you do not have to balance your client's checkbook on your back. That's all I am saying.

To answer your question though, a change of occupancy alone - it could, depending on the importance factor, but not likely only moving from from Residential to Retail. If the live load of the retail is in excess of 100 psf, it will affect the seismic forces, It could also be affected by a change in the wind exposure seen by the structure.

If the local Building Department has other thoughts, I would consider retrofitting in some Simpson UFP or FAP anchors that mount to the side of the concrete stem wall and nail to the side of the sill plate, avoiding the use of new washers and drilling more anchor bolts. Both of these use Simpson Titen concrete screws to mount to the stem wall.

If it's an older residential structure (pre 1988), it may only have sheetrock shear walls. I would seriously consider going to plywood in this case as more than likely, when the building was constructed, half stresses were not used for the gyp walls if seismic governed.

Mike McCann
MMC Engineering

 

[MiketheEngineer]

Call the local building code agency.... They will tell you what they want.

Probably - you need to upgrade anything that increases stresses by more than 5%.

 

[RVSWA]

Reading Msquared48's first reply I was quietly cheering him on, it is an important point with regards to remodels. I want to help people and even knowingly take the occasional time/resource sucking job because I feel like helping someone. BUT! They are creating the condition and generally they do so without knowledge or experience of the impact it may have on the structure. Mike the Engineer was referring to a provision in the Existing Building section of the IBC. There is also ASCE 31 which provides guidelines for the seismic evaluation of building. In my humble experience these things can't keep up with most peoples dreams.

To answer you question directly, I design remodels to be supported by elements that I design to resist the current code loads. As some remodels are proposed, they don't give a clear point of beginning and ending. I provide the necessary elements or upgrades, as a result, I don't have many remodel friends... I've even started a collection of Remodel configurations that I plan to give to my clients (a little booklet) so they don't sell the homeowner the moon without mentioning the impact of their proposals.