Project Studies Threats to Historic Buildings in Portland
By Liza Mickle
In Portland, and potentially statewide, most unreinforced masonry (URM)* buildings have not been seismically upgraded. Building owners face various challenges and obstacles. Many perceive there is no incentive to perform seismic upgrades, and they likely would not do so without incentives because it doesn’t make financial sense. For owners of buildings that are underutilized, have fallen on hard times, or are used for storage or other lower-hazard occupancy, it is generally too costly to make full improvements without some sort of subsidy. At the same time, economic prosperity and development pressures in many Portland neighborhoods has put older buildings at risk, rather than making their rehabilitation more likely. The potential for demolition and replacement of these types of buildings is a real concern. The Portland URM Building Survey report is intended to provide a springboard for considering the wider network of issues and calls for strategies to address these issues.The Portland URM Building Survey Project focuses on unreinforced masonry buildings in neighborhood hubs and corridors outside Portland’s central city. The project includes survey work and analysis of issues and threats to older and historic buildings (generally defined as over 50 years old). Overall, approximately 450 URMs were surveyed under this project, using data provided by the City of Portland Bureau of Development Services (BDS). From the survey group, four building types were selected for further analysis and individual case studies, and a technical report was prepared. The project began in March 2013 and was completed in September 2013. It was funded by a small matching grant from the Oregon State Historic Preservation Office (SHPO).
Survey work — The first phase was an abbreviated (windshield) survey of approximately 450 URMs in eight selected areas east and north of Portland’s Central City. The areas represent a geographical distribution of neighborhood centers or hubs, “main streets” and commercial corridors, as informed by the Bureau of Planning and Sustainability’s Portland Plan and current work on the City’s Comprehensive Plan update. The eight areas include portions of commercial areas in Southeast Portland (SE Foster Rd., SE Stark, SE Milwaukie); Northeast Portland (Sandy Blvd. and NE Alberta); and North Portland (N Lombard). As a follow-up to the abbreviated survey, a Reconnaissance Level Survey (RLS) was completed for over 40 selected buildings, meeting standards established by the Oregon SHPO.
Case studies — Using the survey results, case studies were prepared for four typical building types found in the URM group: 1) one-story commercial buildings; 2) two-story mixed-use commercial buildings; 3) multi-story residential buildings, and 4) special-purpose buildings. The purpose of the case studies is to generally assess the existing buildings, review building deficiencies, if any, and discuss rehabilitation strategies and potential cost factors.
Technical report — A technical report, “North and Eastside Portland Unreinforced Masonry Building Survey Project Report,” generally describes the relative seismic performance of different types of masonry buildings and highlights key issues, economic, planning, and other limitations or challenges. It provides a springboard for considering the wider network of issues with unreinforced masonry buildings, helping us understand the issues are citywide (and also statewide), and strategies are needed to address these issues.
View the whole report at http://www.portlandoregon.gov/bps/article/464830
* Unreinforced masonry (URM) is defined as masonry that has roof or floor loading above 200 pounds per lineal foot and less than a certain minimum amount of reinforcement. Masonry walls that are under-reinforced are therefore included.
Liza Mickle is a Planner with the Portland Bureau of Planning & Sustainability