This past Thursday we met with David Medeiros at the Geospatial Center and made great strides in finalizing what the mapping aspect of our project will look like. We made a preliminary map – the first of what will in all likelihood be many iterations – that simply layered over a parcel map of Oakland that parcels that were identified as Soft Story. While simple in scale, this was a great experience in familiarizing ourselves with the GIS programs.
At the moment, we have much data that we did not yet use in mapping. The sheets that Dana Brechwald sent us are rich in material. However, as Jack noted, we do not as of yet have any data about seismic activity in the region, so we are hoping to find that either via the USGS or potentially Camilo will have a way of acquiring it. Once we have that data, we plan to establish our Vulnerability Metric and generate some kind of heat map detailing which areas are most at risk. And then, by zooming in, one will be able to see which specific parcels are the most vulnerable. We hope to have a fairly finalized map by the end of next week.
Apart from the map, this week we continued working on our project’s website. Having chosen SquareSpace due to its wonderfully user-friendly interface, we began experimenting with formatting and design options. Thus far we have created our home-page and a few drop down menus, but are still deciding what information we want to relay and how best to go about doing so. The city of Oakland sent a postcard to each soft story home a few weeks ago in order to provide information and spread awareness to these residents. However, as a group, we believed the postcard to be both too passive and lacking in immediacy, a problem which we hope to ameliorate with our website. Yet it is a fine line we must walk between being alerting the public that they may be living in, as a participant at one of the community meetings put it, “a ticking time bomb” and being alarmist. The content of the website is to be an ongoing question.
What We Observed and Learned
On Monday we brainstormed about interesting questions that might come up from the preliminary data obtained from the surveys made by the City of Oakland. We expected to be able to find patterns that related socio-economic aspects with people’s preferences and attitudes towards risk, as well as other interesting ways of filtering information beyond the summary provided by our partners. For instance, one question in the survey asked about the level of acceptable damage, or conversely, the level to which people expect the building to comply seismically (this is, whether it will experience minor damage, extensive damage, etc.) and we decided to separate what tenants and owners thought about it. In all cases (tenants, owners, or the whole group), the majority prefers the category “Building will experience damage and disruption to utilities, but no significant damage and it can be occupied during repair”. There were some differences on the percentages, for example showing some 4% of tenants preferring significant damage (vs.less than 2% of owners in that category), which makes sense since, as long as they survive, it is not their investment under risk of loss. However, these numbers are not so directly comparable since very few owners answered the question compared to the number of tenants, which is also an issue on several questions we intended to break down.
A simpler question we thought would be interesting to extract from the database was about the outreach strategy that can be associated with those residents that identified themselves as wanting to keep involved and informed about the program (see figure below). It turns out that most individuals who want to stay connected (roughly 80%), were reached by either postcard delivery to their address or the Yahoo-Groups database the City of Oakland had. We found this a bit surprising since the postcard does not bring much information (or we didn’t find it particularly engaging), but it may be too early to draw conclusions since only a limited amount of residents have responded so far.
On Thursday we convened at the Geospatial Lab in the Earth Sciences library, to begin generating content for our GIS analysis as well as learning the basics of creating a layered map. With David’s help, we set up a project folder and added two layers of mapping data, very simply showing the parcels of land and the locations of the soft story buildings. We learned about the data already present in the GIS database, and how to clean data tables within GIS to make cross-data comparisons.
Through our analysis of outreach data we were able to glean a significant amount of initial results that will be useful for our policy recommendations. However, a lot of these results are not all too different from results that could be determined from Victoria’s initial attempts at analysis; the primary difference being that we got results exclusively for landlords and tenants, a broad categorization we deemed particularly relevant. Our next steps at analyzing our data will be to brainstorm questions that probe a little deeper into demographic differences and how that impacts people’s opinions on retrofitting policy. In trying to understand the impact of gentrification/short term housing on willingness to retrofit, we will try and ask how the amount of time you have lived in a unit and plan on living in said unit impact your decision to quickly and efficiently take steps to retrofit. We also want to try and understand how income level impacts both tenants’ and landlords’ willingness to take on costs or how they perceive an equitable distribution of funding (e.g. small vs. large buildings, poor tenants vs. poor landlords). Ultimately, these next few weeks we hope to gain an even more nuanced understanding of how demographics impact people’s engagement with retrofitting, in an attempt to try and recommend policies/incentives that would help the city be more efficient in pushing for retrofitting.
This week was the first time we had access to all the data necessary to begin our mapping project. We made good progress, laying out initial location and parcel data to begin the mapping process, but their still remain a few critical steps to go. Our ultimate goal is to overlay the pre-existing vulnerability data provided to us by ABAG on top of our existing map so that we can identify particularly vulnerable soft-story regions. Once this has been done we also plan on creating a few maps that zoom into these vulnerable regions, so policy-makers can see what the density of soft story housing is like there.
From the spreadsheet defining the soft-story building descriptions, we realized that we have different potential factors that could lead to fragile structural behaviors. First, the year of construction of the building relates to the kind of wood material the building has. Given that the seismic codes and requirements have evolved and improved with the years, it is evident the direct relation between structural safety and new engineering practices. Second, the wall density (relation between the amount of walls and total constructed area) plays also an important role; there are buildings with only a few walls that make the structure potentially unsafe, and given that we are looking specifically at soft-story buildings, which by definition have some missing walls in the first floor, this parameter is fundamental. Third, the number of stories has a significant impact on the behavior of the soft story buildings because we are expecting damage concentration on the first floor, which is supporting the weight of all the floors above it. Finally, the geometric irregularities (if walls are particularly concentrated in certain places rather than more or less equally distributed along the area of the building) in the buildings could also have a major impact on the building vulnerability. To evaluate the extend at which these parameters play a role in our analysis, we will model some extreme cases using FEM807 (maximum and minimum number of stories, oldest and newest year of construction, etc), which can give us a fair idea of how vulnerable the buildings are. We would like to analyse more buildings but given the time constraints, and limited information about the buildings, this may not be feasible. However, if we are able to find buildings that can clearly be identified as having an extraordinary amount of risk we would like to point those out on our map.
Our website, to be made on SquareSpace, will contain a condensed and user-oriented version of the City of Oakland’s existing Soft story page, in which we will add our own analysis and data work for the use of the Oakland Resilience Team. Our policy recommendations, as well as our ArcGIS analysis will remain partitioned from the rest of the content, so that it can be removed by the city of Oakland’s staff, should they want to use the website for outreach. We will also include a section on future work, so that we may describe how future Stanford students may contribute to the City of Oakland’s ongoing work.