Earthquake home retrofit

[Raidingtime]

Thought this topic maybe of interest to many people within this website.

I'm looking to retrofit my 1 story 1100 sq.ft home with the typical crawl space and perimeter up side down T foundation.

Any information regarding how to retrofit a typical home is appreciated. What kind of equipment is recommended?

I've looked into this procedure on my own and so far I've come to this conclusion. I need a sheer transfer tie and foundation anchor attached every 16 inches with bolts and screws. Does this sound right? Is it recommended to choose concrete bolts that fasten with an impact nut or with adhesive?

Thank you!

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[Foreverlost]

Bottom line............consult an architect. Factors including building weight, style of fasteners, etc. will determine possible choice. At this point, also looking at this option, there doesn't appear to be regulations to insure a proper retro or contractor with proven experience. I'd hate to buy snake oil, know what I mean.

If you don't have to live or work in the CSZ, is moving cheaper? Following the news years later (Katrinia & Sandy); some areas will not be rebuilt for generations. Other areas, the insurance giants are waiting for property owners to die & thus never settle claims.

Foreverlost,

 

[Cryobot]

Good advice. Call around and chat with local architects. The can make recommendations on what to buy and install over the phone and email based on key info. Most are reasonably priced. I was charged $250 for a window installation I did. Sent some photos and attic pics, year the house was built, and what I wanted to do. It can save you from wasting time and money on upgrades that may not work.

 

[jbett98]

When was your house built?
When I was a contractor in the Portland area, my specialty was building custom additions to existing homes and I installed a few whole house seismic upgrades.

 

[Hook686]

I trust you will consult with an architect-engineer firm that has a registered structural engineer on staff. Seismic analysis is not for the self made man.

 

[Provincial]

Unless your existing foundation has adequate strength (strong enough concrete mix and proper rebar installed) you are not going to be able to upgrade at a reasonable cost.

With an inadequate foundation, your only choice may be to tie the structure to the foundation as well as possible and hope the quake isn't too strong.

Moving to an earthquake-qualified house will be less expensive than an upgrade, since few home buyers (or sellers) consider earthquakes in their decisions.

 

[Raidingtime]

Unless your existing foundation has adequate strength (strong enough concrete mix and proper rebar installed) you are not going to be able to upgrade at a reasonable cost.

With an inadequate foundation, your only choice may be to tie the structure to the foundation as well as possible and hope the quake isn't too strong.

Moving to an earthquake-qualified house will be less expensive than an upgrade, since few home buyers (or sellers) consider earthquakes in their decisions.

I'm aware of this predicament. I will probably end up going with retrofitting the best I can by myself to reduce costs. I realize the best option is to consult an engineer and use their advice. The thing is is that my home and property is only worth $170k. This make it not as cost effective to spend the extra money on getting a qualified retrofit.

 

[Charliehorse]

Possibly look into how manufactured homes are cabled down and then adapt to your foundation. Would probably include pouring piers to cement the cable anchors to. Just a thought for the do it yourselfer.

 

[Benchrest]

I would seriously consider consulting a structural engineer.

Seismic systems are, systems - Improvements to an older home that seem to 'make sense' have potential to do just the opposite.

 

[navin r]

Long time lurker, new member, current SoCal resident, probably eventual PNW resident, if you're going to improve your house yourself w/o the help of a professional, there is some good information and diagrams from LADBS on foundation bolting here:

http://ladbs.org/LADBSWeb/LADBS_Forms/Publications/anchor_bolting.pdf

And good information and diagrams about one story wood frame construction from LADBS here:

http://netinfo.ladbs.org/ladbsec.NS...FILE/ib-P-BC 2002-004 TypeV Sheet-6-11-02.pdf

 

[thorborg]

A good start if you have gas, is to make sure your water heater and stove are strapped down, and you buy (and maintain) earthquake insurance before the next event, as you won't be able after, for a few years.
Beyond that, (and bug out kit) I put in the Chicken Little category on a single level home. The Chicken Little part, is not advice to you, just my life and perspective.

 

[jbett98]

I zip tied a wrench to my gas meter so I can shut it off in a hurry.

 

[Foreverlost]

Most of my neighbors couldn't give a chit, they have natural gas to their homes. If'en their house catches on fire, there goes several more on the block.

Fire departments still keep the doors closed to prevent thefts of equipment. My money says without electricity and structure damage to their building, fire fighting equipment isn't going anywhere. Oregon is dumb. My house, when living in So-Cal had an earthquake valve on the gas meter, auto shutoff in the event of a quake!

Bug out kits: After reading some of the first reports of the CSZ, getting out of Dodge was top on the list (ACoE dam failures). Sad but true...........I can't get there from here. Too many tall structures, power lines, poles, overpasses, bridges, will fall/fail. ODOT has an earthquake report if you search their website. It is for general public viewing. City fathers, etc get a more detailed report. My only option is to shelter in place, if still living here.

My bottom line: I don't have to live here...........5% or 6% paid to a realtor to sell my property is cheaper than a deductible on earthquake insurance. And there is no worry about, is my block or neighborhood going to be rebuilt. Without electricity, gas, water, sewage, ect. no use rebuilding till those are in place first. Will my stupid neighbors have insurance to rebuild?

Hasta la vista, baby

Foreverlost,

 

[kenboy]

I zip tied a wrench to my gas meter so I can shut it off in a hurry.

DITTO

 

[powersbj]

Seattle had a major study on earthquake retrofits after the sanfran quake I have a comprehensive packet somewhere, it includes how to tie into your foundation, stiffen up your ponywalls etc. I'll see if I can find it and scan it for everyone, I don't believe there wad any sort of copyright on it.

 

[slingshot1943]

Your building dept. should have accepted standards that are approved without engineering on houses.

 

[jbett98]

Do you know why there are no architects in heaven?

Because Jesus was a carpenter!

 

[clearconscience]

I checked into earthquake insurnace and the premiums and deductables make it ridiculous.
They usually won't even cover half your cost, and your deductable will be so high it's worth it to save that money for buying new stuff.

 

[DuneHopper]

Why its on the topic, Earthquake insurance in Oregon less then 2 out of ten homes are inured for Earthquakes. It not cheap usually and cost about as much as flood depending on area. Its not a standard add for most insurers for Oregon. Having a strong built home is good, having insurance in case is as well. I learned about this several years ago, went to put quake insurance and the gal thought I was joking I was in California in the 89 quake saw my truck clear the driveway floor by two feet bouncing off the concrete and it also left a 2foot gash in the foundation lucky was the opposite side the gas was on.
Had insurance then, and do now.

 

[erudne]

when I was trapped in Kali I lived through several Big Quakes and my pool did not even crack. much damage is dependent on the wave length and duration of the quake, as well as proximity to epicenter. Bert Gummer prepped for a Nuke war and ended-up facing Graboids