Browsing by Author "Mayoral, J.M."
Now showing 1 - 2 of 2
Results Per Page
Sort Options
Item Assessment of fragility models based on the Sept 19th, 2017 earthquake observed damage(2019) Román de la Sancha, A.; Mayoral, J.M.; Hutchinson, T.C.; Candia, Gabriel; Montgomery, J.Seismic vulnerability evaluations of buildings and critical infrastructure in densely populated cities strongly rely on fragility curves to estimate the probability of reaching or exceeding a given state of damage. Currently, however, the predicting capabilities of these models is limited. This paper presents a critical study of the accuracy of fragility curves for buildings, urban bridges, tunnels, overpasses, main roads, avenues and metro stations, aiming at establishing its advantages and shortcomings, when using them in seismic vulnerability and resilience assessments. Data gathered from one of the most damage areas during the 7.1 Mw September Mexico-Puebla 2017 earthquake was used in this study. Measured peak ground accelerations, PGA, and permanent ground deformations, PGD, along with appropriate fragility curves were used to establish the probability of having minor, moderate, large damage or collapse of buildings and critical infrastructure components. The damage on the study area documented during field reconnaissance was compared to that which would have been predicted using the fragility curves. Although in some cases, there was a good agreement between predicted and observed damage, overall it was clearly identified the need for developing fragility models that account for soilstructure interaction, and specific structural and ground conditions, to ensure a more reliable risk characterization of the City building stock and infrastructure during an earthquake.Item Observed building damage patterns and foundation performance in Mexico City following the 2017 M7.1 Puebla-Mexico City earthquake(2019) Franke, Kevin W.; Candia, Gabriel; Mayoral, J.M.; Wood, Clinton M.; Montgomery, Jack; Hutchinson, Tara; Morales-Velez, Alesandra C.The September 19th, 2017 M7.1 Puebla-Mexico City earthquake introduced strong ground motions into the Mexico City basin, which contains very soft lacustrine soils, dense urban infrastructure, and millions of inhabitants. As a result, 38 mid-rise structures collapsed and several hundred more were damaged. This paper reports the observations related to building performance, damage patterns, and foundation performance made by the two UNAM-GEER engineering reconnaissance teams sent to investigate the geotechnical aspects of the earthquake. The methodology used to perform building damage mapping following the 2017 event is described. Comparisons are made between the observed building damage patterns following the September 19th, 1985 and the 2017 earthquake, and the distinct differences in the damage pattern distribution between the two earthquakes are summarized. Overall, building and foundation performance were observed to be quite good during the 2017 event, especially when compared to the 1985 event. Structures that were observed to be heavily damaged or collapsed were all built prior to 1985, and incorporated poor structural design and/or construction which resonated with the soil column on which they were constructed, and/or were built upon very soft soils that contributed to significant foundation deformations. Detailed building damage pattern maps of specific neighborhoods that were investigated are provided, and lessons learned from this event are summarized.