PROBABILISTIC ASSESSMENT OF EARTHQUAKE-INDUCED DEBRIS GENERATION USING PBEE METHODOLOGY

Mesta C.; Santa-Cruz S.; Kahhat R. · World Conference on Earthquake Engineering proceedings (2021)

Resumen

Buildings collapse due to the occurrence of seismic events in urban areas could generate a great amount of debris and waste, depending on buildings structural fragility, intensity of the ground motion and materials of structural and non-structural elements. Providing reasonable predictions on the size, type and location of earthquake-induced debris is of critical importance for developing effective disaster risk management plans, that could improve emergency response and recovery phases (i.e., selection of evacuation routes, debris management possibility of recycling practices, etc.). In this article, we present a methodology to estimate debris produced by the partial and total collapse of buildings after an earthquake scenario at urban scale, using the conceptual framework of Performance-Based Earthquake Engineering, PBEE. The proposed methodology includes three steps: 1) GIS-based exposure modeling, where the residential building stock and its material composition is evaluated, 2) fragility modeling, where fragility curves (expected percentage of debris vs. seismic intensity) for different building typologies are generated within the PBEE framework, and 3) scenario-based seismic risk analysis, developed to estimate the amount of debris and its spatial distribution. The methodology was applied to a case study to demonstrate its usefulness and capability to support decision-making for seismic risk reduction at a city scale. In a retrospective analysis, a similar scenario to the 7.9 Mw earthquake that hit Pisco city (Peru) in 2007 was simulated in order to estimate debris generation. The proposed methodology estimated a volume of debris of around 1’196,000 m3, which is very close to the official amount reported by local authorities, 1’000,000 m3. Debris estimated with this method were mainly constituted by concrete (34%), clay bricks (27%) and mortar (27%). Moreover, the GIS-based analysis shows that debris distribution across the city was diffuse and debris removal was probably time-consuming with a great demand of truck-trips. In addition, it is most likely that critical infrastructure accessibility (i.e., roads, schools, hospitals) was affected by the debris accumulation. However, these findings also suggest that it could have been a good opportunity to start novel recycling practices of debris (e.g., concrete debris) in the region. Finally, the debris fragility curves developed in this study could be used for earthquake-induced debris assessment in other cities with similar building typologies.

Instituciones: Pontificia Universidad Católica del Perú