This Grant for Rapid Response Research (RAPID) will support a collaborative team of researchers from five U.S. universities to collect data to document the performance of reinforced concrete buildings during the Puebla-Morelos, Mexico earthquake of September 19, 2017. The ground shaking from this earthquake caused widespread damage to buildings in the epicentral region, as well as in Mexico City (approximately 120 kilometers from the epicenter). In Mexico City, approximately 40 buildings collapsed, and over one thousand structures have been identified with moderate to major structural damage. The 2017 earthquake, having impacted an area that had already been shaken by a strong earthquake in 1985, provides an opportunity to learn about the effectiveness of reinforced concrete building repairs and retrofits made after the 1985 earthquake, as well as an opportunity to study how modern and older, unrepaired reinforced concrete buildings performed during strong ground motion. The majority of collapsed buildings were constructed prior to 1985 before there were major seismic revisions to building codes. There were also a few cases of newer and retrofitted buildings that also sustained damage. Mexico City has soil conditions ranging from stiff rock to very soft soil, producing a diverse set of ground conditions affecting buildings that can facilitate understanding of seismic building performance not only in Mexico, but also in the United States. Because the United States and Mexico have similarities in reinforced concrete building construction, the collected data from this earthquake will contribute to better building design and performance assessment methods, numerical simulation methods, and earthquake intensity indices in both countries, and help foster safer buildings and more earthquake-resilient communities. The collected data will be archived and made publicly available in the NSF-supported Natural Hazards Engineering Research Infrastructure, Data Depot and Reconnaissance Integration Portal (http://wwww.DesignSafe-ci.org). Graduate students will participate in the data collection and gain valuable post-earthquake field experience. The project team will disseminate its data collection and research findings through a webinar.
The goal of this RAPID project is to collect perishable data on reinforced concrete building damage that can be used towards understanding and improving seismic performance of buildings and the resilience of communities in the United States. The data collection in Mexico will be conducted in collaboration with researchers and engineers in Mexico and include the following activities: (1) survey buildings built near recording stations with emphasis on retrofitted buildings, buildings that survived the 1985 earthquake, and modern buildings, (2) document damage to non-ductile reinforced concrete buildings for calibration of existing methodologies used to identify vulnerable buildings in the United States, (3) map damage to test commonly assumed correlations with earthquake intensity indices such as peak ground acceleration, peak ground velocity, peak ground displacement, and peak or discrete spectral values of acceleration, velocity and displacement, (4) document the performance of instrumented and base-isolated buildings, (5) deploy accelerometers on damaged and undamaged reinforced concrete buildings with and without retrofits to record ambient vibrations and obtain building dynamic properties, (6) evaluate numerical models of reinforced concrete buildings by subjecting them to ground motion records obtained nearby and compare the numerical estimates and observed performance, and (7) study relationships between building performance and soil conditions.
