earthquake retrofit strapping

[swilson]

If you don't know what earthquake retrofit strapping is, it's basically a series of steel plates and bolts that connect the wood structure of a home to its concrete foundation wall. Today CA building codes require homes to be attached firmly to their foundations, however older homes were built simply resting on their foundations, which is fine until an earthquake hits and causes lateral movement, with the unattached home literally sliding off the foundation wall.

How intrested would you be in having your home retrofitted, and/or do you know others who would be? I'm asking because I've installed these before but only as part of a larger project and not just by itself, and thought this would be a good place to ask.

I'm not offering any service (yet), I'm simply seeing whether or not there's any intrest to have earthquake retrofit strapping installed by a licensed professional.

[Saym14]

services offered forum ?

[Sanderhawk]

Interesting. When I was a framer 25 yrs ago we always lag bolted the frame to the foundation.

[Beantown]

If you don't know what earthquake retrofit strapping is, it's basically a series of steel plates and bolts that connect the wood structure of a home to its concrete foundation wall. Today CA building codes require homes to be attached firmly to their foundations, however older homes were built simply resting on their foundations, which is fine until an earthquake hits and causes lateral movement, with the unattached home literally sliding off the foundation wall.

How intrested would you be in having your home retrofitted, and/or do you know others who would be? I'm asking because I've installed these before but only as part of a larger project and not just by itself, and thought this would be a good place to ask.

I'm not offering any service (yet), I'm simply seeing whether or not there's any intrest to have earthquake retrofit strapping installed by a licensed professional.

walls are typicly installed with anchor bolts thru the sill plates to the foundation, and not just resting on the foundation - if an earthquake hasn't knocked the building down yet, wind forces can too. simply adding strapping will not resist lateral forces, shear walls need to be properly designed by a liecensed profesional (architect, structural engineer) and use proper hold downs. are you a contractor, architect or engineer? you need to be the latter 2 two offer these services in CA.

[swilson]

walls are typicly installed with anchor bolts thru the sill plates to the foundation, and not just resting on the foundation - if an earthquake hasn't knocked the building down yet, wind forces can too. simply adding strapping will not resist lateral forces, shear walls need to be properly designed by a liecensed profesional (architect, structural engineer) and use proper hold downs. are you a contractor, architect or engineer? you need to be the latter 2 two offer these services in CA.

Please actually read my entire post before telling me I'm wrong about everything.

1. I'm well aware how new construction today is bolted together. I'm talking about older homes, as in midcentury and earlier, that are not anchored to their foundation.

2. When properly installed, retrofit strapping adds a 60% increase in allowable (higher for actual) loads for earthquake and wind... so yes it really does.

3. I never offered any type of service. Had you read my post you would have seen where I stated, in no uncertain terms, that I'm seeing if people are intrested in this type of retrofit at all.

4. Yes, I am a licensed general contractor, and no, you do not need to be an architect or structural engineer to install retrofit strapping.

[Beantown]

well for the sake of discussion, just because a wall is anchored down to a foundation weather it be straps, anhor bolts, hold downs, does not guarantee seismic resistance. the anhors, straps, holdowns etc have to be desiged to resist shear, overturning moment and uplift, which is transmitted by shear walls to the building foundation thru these connections. typicly, wood frame construction resists shear well if built and designed properly to do so, but the existing structure should be evaluated by a professional architect or engineer who don't install, but contractors do.

if a structure was actually built without a connection to the foundation, i would question the integrity of the structure to resist and transmit the forces.