The building that is fine until the ground moves

So one of the upgrades that we do pretty often is when either an older building has not been designed for seismic or when there's a new use for an older building. And it gets it basically gets flagged when the permit is submitted. So. For example, if you have an apartment complex that maybe is sitting on top of like a carport style parking garage, we call that a soft story when the cut. You can think of it like it's in if the first floor is lighter, essentially, and more flexible than the floors above it. That's called a soft story. And that has a much higher likelihood of collapse during an earthquake than buildings that have a stronger stiffer floor on the first floor. Often we'll build we'll build the first floor out of concrete or brick and then we'll build the floors above it out of wood just to avoid that effect and high seismic zones. So. None of this shows up in a sunny day walkthrough because it's expensive. It's hard to find. And the truth is, is you're not going to have the issue until that earthquake hits. But not knowing is it necessarily a cheaper position. It's just the quieter one until that day. I can tell you about a case that I worked on. So in downtown Seattle, you know, there's a. It's a high density area. Right. So this client was taking a single family home and turning it into a duplex basically. So the first floor was going to be a unit. The second floor was a unit. And it had this 80 style architecture. And I'm not sure if you guys have seen these houses before, but where the bottom floor actually has a smaller footprint than the floor above it. And it has like a, you know, like a two to four foot cantilever hanging over that first that first floor level. So first of all, it had that original architecture. And then the home, they built a porch off of that four foot cantilever that was six feet wide. So now I'm looking at a 10 foot cantilever. So this second story was considerably bigger and stiffer than the understory. And so it was a soft story or essentially a seismic issue. So what happens is when you have this kind of a layout and it's on soft ground that's already amplifying your seismic forces, you're going to get a lot of movement in that, in that, in those higher floors. So what we did for this project in order to stiffen up that first floor was we treated the bottom basically like an open carport. And so what we did was we had just two foot wall sections that are called portal frames. And then under those two foot wall sections. So at each corner, we did a two foot section and right in the middle, we did a two foot section. And then we did a nice footing underneath it. And basically what it did was it added stiffness and weight to that first floor. So that was the first thing regarding seismic was to was trying to get rid of that soft story. And then the second major upgrade for seismic was to go into the crawl space and to add lateral hangers, essentially every four feet in that crawl space. So with new construction, we use anchorage, but, you really can't drill into concrete too well. Once the once the slab is existing and you're in like a 20 inch deep crawl space. So they have something called lateral hangers. Just a connection type and make sure essentially that the building doesn't slide off of its foundation.