The research project “Quantifying the Performance of Retrofit of Cripple Walls and Sill Anchorage in Single-Family Wood-Frame Buildings (PEER-CEA Project)” received an Award of Merit in the Research Category from the 2021 Structural Engineers Association of Northern California Excellence in Engineering Awards (EiSE) Program. Awards in this category are for "outstanding achievement in the development of structural engineering practice, standards, research documents or design guidelines."
The Awards Committee stated that “the jurors were impressed with the amount of collaboration that was required between all of the contributors and the number of working groups. They also thought that the ability to compute so much data and run so many analyses was innovative, as the team expected the computing to take [years] but they were able to accomplish it in weeks. Additionally, because the end product is designed for home owners and non-engineers to promote retrofitting of single family homes, this project has a significant contribution to the public.”
Yousef Bozorgnia, project Principal Investigator, noted that "we appreciate this award that recognizes the collaborative work of the project team of over two dozen academic researchers and expert practitioners for the past four years. The data and information gained from the project will be impactful beyond the project itself."
Grace Kang, project coordinator and PEER Communications Director, said that “on behalf of the project team and PEER, we are delighted to receive this award and the recognition for the project team's work. A complex problem was tackled by the expertise in each working group, with the groups working collaboratively to show that a simple retrofitting investment today can save significant costs in repairing damage that would be caused by a future major earthquake. The findings of this project affects not just northern California, but all homeowners in California.”
Project abstract: In California and many other states, inadequate bracing and anchoring is a major cause of earthquake damage in older wood-frame houses that have a first floor above a crawlspace. Past quakes have caused varying levels of damage in these homes, resulting in costly repairs even if the houses did not collapse. Many homeowners may not have enough financial resources to cover such repairs. Hence, understanding how older, wood-frame houses benefit from earthquake retrofitting is important.
The objective of the project “Quantifying the Performance of Retrofit of Cripple Walls and Sill Anchorage in Single-Family Wood-Frame Buildings (PEER-CEA Project)” is to provide scientifically based information (e.g., testing, analysis, and resulting loss models) that measure and assess the effectiveness of seismic retrofit to reduce the risk of damage and associated repair costs of wood-frame houses with cripple wall and sill anchorage deficiencies as well as retrofitted conditions that address those deficiencies.
To understand how retrofitting reduces earthquake damage and repair costs, project researchers first identified different characteristics or “variants” of home types, such as the number of stories (one- or two-story), era or age of construction, interior wall and ceiling materials, exterior cladding material, and height of the cripple walls. Experimental tests of full-scale cripple wall assemblies with different construction materials, for unretrofitted and retrofitted conditions, were conducted in order to validate analytical modeling. State-of-the-art modeling and analysis was conducted to estimate how retrofits can reduce losses in vulnerable housing styles in California. Workshops with experts generated realistic repair cost data.
A brochure targeting the non-engineering audience summarizes the benefits of retrofit in terms of potential savings of repair costs in the event of a major earthquake. This document, as well as the research methods and data can be viewed at: https://www.peer.berkeley.edu/cw-woodframe