Hi everybody, we down here at the ep is a center which is our pop up space down here in San Francisco where we operate a store front to educate the policy from the home owner who has center which is our pop up space down here in San Francisco where we operate a store front to educate the policy from the home owner who has never done anything in the house to the most advanced structure engineers we have working around here. We were going to here from kelly to talk a little bit about San Francisco. How are you doing kelly . Very well, thank you for having us here. In front of us, we have a typical soft story building. When i see this, i think this is some of the most beautiful architecture our city has. A lot of people dont know these are problematic buildings. Why dont you tell us about some of the risks he we have in these buildings . Soft stories are vulnerable in past earthquakes and the northridge earthquake to this type of building and character of building. When we talk about the soft story, what were talking about is generally a ground story that has less wall or other pwraeugs to resist the lateral forces that might be imposed by the earthquake. So were looking for something that is particularly weak or soft in this ground story. Now, this is a wonderful example of what some of the residential buildings that are soft stories in San Francisco look like. And the 1 thing that i would point out here is that the upper force of this building have residential units. They have not only a fair amount of wall around the exterior of the building but they also have very extensive walls in the interior and bathrooms and bedrooms and corridors and everything that has a certificate amount of brazing yea its significantly less country srabl in those stories. Now very often, we get even a garage or storage or sometimes commercial occupancy in this ground story. That very often not only has a whole lot less perimeter wall but it often has little or no wall on the interior. That wall is the earthquake bracing and so he see very significant bracing in the top floor and very little on the bottom. When the earthquake comes and hits, it tries to push that ground floor over and theres very little that keeps it from moving and degrading and eventually paoerblly keeping it from a collapse occurring. So we know theyre vulnerable because of this ground story collapsing is this only a problem we see in sentence france . San francisco . No, this is certainly a national problem. More acute in western but more up to california, washington, moving out into other states. This kind of building exist and this kind of building is vulnerable. When youre involved with the community safety, this is a different way of thinking about these types of things. We had a Community Group of over 100 people involved and upper 1 of them. Tell us about how that conversation went. Why did we decide as a city or a community to start fixing these types of buildings . There were a lot of aspects that were considered well beyond just the engineering answer that these are vulnerable. And that effort brought in a lot of people from different aspects of the community that looked at the importance of these buildings to the Housing Stock and the possible ramifications of losing this houbgs in the case of an earthquake. The financial implications, the historic preserve vacation s implication as you mentioned, these are very handsome looking buildings that are importance to the tourist city ask which make San Francisco something that people are interested from outside in coming and visiting. Its such animation story when you think about the 10 years that the community spent talking about this seurb but we actually did something about it. Now we have an order unanimouses put in place to protect 100,000 residents in San Francisco and retrospective in 2020. So on behalf of residents and employees in San Francisco, we want to say thank you for the work youve done in pushing this forward and making people more aware of these issues. And it was a fantastic community effort. So in an earth quake, what happens in these kinds of buildings . What happens when an earthquake comes along is it moves the ground both horizontally and vertically. Its mostly the horizontal that were worried about. It starts moving the Building Back and forth and pushing on it. When you see im pushing on it, the upper stiff of the wall stay straight up but the lower floors, they actually collapse just like i did there. Luckily, we can put this building right back up where it came from so its a lot easier. Now kelly, obviously these arent real frame walls here but when you talk about buildings, what makes the property for stiff . The easiest and most costeffective type of bracing you can put in is either put in a brand new wall or to potentially go in and strengthen a wall thats already there where you dont need to have an opening is where you maybe have a garage door or access to commercial space, you might go to a steel frame or other types of bracing systems that provides the strength and stiff if necessary but at the same time, allows continued use of that area. But some combination of walls or frames or other tools that are in the tool kit that can bring the building up to the strength thats required in order to remove the vulnerability from the building so that when ground shaking comes, it in fact is a whole lot more resistant and less vulnerable. Ideally, this story down here would be made as strong and stiff as the floors above. If im a property owner, what is the first thing i should do . The first thing you should do is find professional that can come in and help you evaluate your building in order to, 1, figure out that indeed it does need to be retro fitted and 2, give you some idea of what that retro fit might look like. And third, evaluation and design to help you determine the retro fit requirement. Well kelly, i cant thank you enough for being here today. Thank you so much for your wealth of information on how we can take care of our soft story problem in San Francisco. And you the viewer, if you have any questions, please feel free to visit our website
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