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Thread: Seismic bolts

  1. #1
    Join Date
    Sep 2010
    Location
    La Mirada
    Posts
    22

    Default Seismic bolts

    Hello my Inspection Brothers,

    I am fairly new to the industry, so bare with me. I inspected a house in South Gate, CA built in 1928. It is my understanding that in 1933 (After the Long Beach eartquake) the California State Legislature on April 10, 1933, required buildings to be earthquake-resistant. That being said how would I report on this building's foundation as it did not have or require seismic bolting at that time. Would I recommend a retrofitting of the foundation?

    Your prompt response would be greatly appreciated

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  2. #2
    Join Date
    Mar 2007
    Location
    Plano, Texas
    Posts
    4,170

    Default Re: Seismic bolts

    I'm not in a earth quake zone but why would you not report the facts?

    Jim Luttrall
    www.MrInspector.net
    Plano, Texas

  3. #3
    Join Date
    Sep 2010
    Location
    La Mirada
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    22

    Default Re: Seismic bolts

    What I am asking is how would I word it on my report?
    Thanks again


  4. #4
    Join Date
    Mar 2007
    Location
    Knoxville, TN
    Posts
    2,446

    Default Re: Seismic bolts

    You are inspecting a house that was built 5 years before the "pre-33" earthquake codes kicked in.
    Without getting into a lengthly discussion, a good portion of the 1933 code had to do with un-reinforced masonry. In the 70's (if I remember right) there was a code requirement for commercial and apartment buildings to do a retro fit and install earthquake anchors to tie the framing system into the brick walls. That's why you see a lot of square steel plates on the exterior of old brick buildings. The joists were set in pockets in the brick walls,m but were not anchored at all, so when the walls moved during an earthquake, the joists dropped out of the pockets.
    There were also framing issues in crawlspaces that needed correction to make them earthquake safe. I'm not sure when that requirement went into effect.

    I left So CA in 94, so I have forgotten a lot of the requirements that the code people set up.

    I guess you need to find out if homeowners were required to bring their houses up to current earthquake codes as a matter of course, or only when there was a structural renovation done that a permit was required.

    To me there is a big difference between a retrofit that was "required" but not done, and one that is "suggested" because it would be a good idea.

    The other thing is that is has apparently survived several large earthquakes. I know of a couple in the 50's, the 71 Sylmar, and several in the 80's and 90's.

    BY the way, you have not lived until you are in a crawlspace DURING an earthquake. In 94 I was in a crawlspace in Long Beach during an aftershock. What a ride.


  5. #5
    Join Date
    Mar 2007
    Location
    Plano, Texas
    Posts
    4,170

    Default Re: Seismic bolts

    Quote Originally Posted by Edward Rodriguez View Post
    What I am asking is how would I word it on my report?
    Thanks again
    For me just how your posed the question here except in a first person, declarative voice. "There are no seismic reinforcements on the foundation in the crawl space." Then give the recommendation you would give your mom if she was to buy the house.
    To me it matters little if it is "gradfathered" since earthquakes do not read the code book or the calendar.

    Jim Luttrall
    www.MrInspector.net
    Plano, Texas

  6. #6
    Join Date
    Jul 2008
    Location
    Lancaster, CA
    Posts
    153

    Default Re: Seismic bolts

    I definitely recommend documenting your observations in regards to whether or not a home's sill/sole plate is bolted to the foundation or not. You should also note the lack of un-sheared exterior cripple walls, and the presence of any retrofitting that you have seen during your inspection. I also generally recommend the buyer obtain any copies of documentation/permits that would accompany the retrofitting.. as I don't care to co-sign some DIY retrofitting that may have little structural value. If an older crawl reveals that the posts/piers/beams or girders lack positive connection.. that gets reported as well.

    This stuff is important enough that if for any reason you can't safely inspect all areas of a crawl space, ensure that you document *any* reasons you were unable to do so.

    On occasion, I've been on site with some foundation specialist co's recommending 5 digits in retrofits to bolted construction. Some idea's of approved retrofits can be found here.. likely not a whole lot different in your area of CA. The link is a .pdf from LA building and safety... but I have done similar much farther south.


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