Thursday, February 9, 2012

Earthquake Retro-Fitting Conundrum


So, for those of you following along, after we got the basement gutted we realized that there is no earthquake retro-fitting done...

Big, tall, long, skinny Victorian sitting on a great new foundation with no Earthquake retro-fitting...
Super Duper.
Since we plan to grow old and die in this place (we mean it this time REALLY!!!) the chances of a good shaker happening are pretty much 100% so earthquake retro-fitting is not optional.

I took a course in DIY earthquake retro-fitting several years ago...Codes have changed since then but basically for a three story house you need to apply plywood shear walls to oh, 80% of the exterior walls.

Here's a pic of the approved floor plan for the basement 3-2 apartment.

Does anybody see anyway in H-E-double hockey sticks I can do that?
Stupid windows letting in all that light and allowing for egress...

The red lines are the places where I think its possible to apply plywood shear walls.
The green lines are where I think its reasonably possible to do without jumping through ridiculous hoops...
Even if I did all the red areas that still would be far below what I need.

Time To Call In The Pros
I've so far had two well respected Earthquake retro-fitting contractors come in and check out the space...
In a nutshell they both said the same thing....
That because of the existing conditions that they would only want to shear the green areas.
Theres just two much stuff in the way at the red areas.
They also both said that the building is too complicated for them to do the job without an engineered plan....

It Gets Better
Guess what the WAG's from the contractors were?
~$20k plus engineering and permit fee's!!!
I've talked seriously with one engineer so far and he wants $1000 to do the site visit and work up a plan and an additional ~$6k to do the plans for the permit!?!?!?

Holy-Freaking Moly.....where are we going to come up with an additional ~$30k to have the pros do this?

My Ideal Solution
Find an engineer who can figure out a way to strengthen just the green areas and have that magically be enough and have the solution be something that I can do myself....oh, and have the engineers fee's cost A LOT less than $7k.....

No Problem Right? 

Hurray for our Dream House!!


Joel said...

What are the requirements for the shear wall?
Maybe what you can do is come up with an equivalent wall with the length of wall you have to work with. I can see two things to which you need to pay attention. One is the crippling/failure of the wood of the panel itself. The other is the capability of the fasteners which secure it to the foundation. You can make the panel thicker to improve its capability, and then install beefier fasteners to get the load out.
Alternately, maybe what you can do is install a pair of steel cable diagonals at a couple of key spots. Anchor those bad boys into the foundation, and put some big honkin' bolts at the top into your structure.

The MadScientist said...

They don't tell you what the requirement is.
In the buildinng codes there is a precriptive method but that won't work here.

So, I need to have an SE analyze the structure to figure out what the loads are and what needs to be done to strengthen the structure.