Seismic response of bridges with cellular foundations built in soft clay

Juan M. Mayoral, Miguel P. Romo, Francisco A. Flores

In the proceedings of: GEO2011: 64th Canadian Geotechnical Conference, 14th Pan-American Conference on Soil Mechanics and Geotechnical Engineering, 5th Pan-American Conference on Teaching and Learning of Geotechnical Engineering

Session: Earthquake Engineering & Geophysics

ABSTRACT: A new foundation system based on structural cells has been used for supporting the columns of the elevated section of the 12th Metro Line, in Mexico City. This study consists on a numerical simulation employing a three-dimensional finite element model developed with the program SASSI2000, of one of the critical supports located in the so-called Lake zone, known by its difficult subsoil conditions. Clays in this region present low shear strength and high compressibility. The system response was computed for a typical seismic scenario, such as that prevailing at the zone, which assumes a potential Mw=8.2 seismic event. The cellular foundation is comprised of a rigid slab structurally tied to perimeter concrete walls, also structurally connected to each other. The computed upper deck acceleration is less than a half of that obtained directly from the recommended response spectra compiled in the Mexico City building code.

RESUMEN: Un nuevo sistema de cimentación basado en celdas estructuradas va a ser empleado para soportar las columnas del tramo elevado de la Línea 12 del Metro de la Ciudad de México. El estudio aquí presentado, consiste en la simulación numérica, usando un modelo tridimensional de elementos finitos desarrollado con el programa SASSI2000, de uno de los apoyos más críticos localizado en la denominada zona de Lago conocida por sus difíciles condiciones del subsuelo. Las arcillas en esta región presentan una baja resistencia al esfuerzo cortante y alta compresibilidad. La respuesta del sistema fue calculada para un escenario típico, como el que prevalece en la zona, asumiendo un evento sísmico de magnitud Mw = 8.2. La celda estructurada está conformada por una losa rígida conectada estructuralmente a muros perimetrales de concreto también conectados entre sí. La acceleración máxima calculada en la parte superior del tramo elevado es menor que la mitad de la obtenida directamente del espectro de diseño propuesto por el reglamento de construcciones de la Ciudad de México.

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Cite this article:
Juan M. Mayoral; Miguel P. Romo; Francisco A. Flores (2011) Seismic response of bridges with cellular foundations built in soft clay in GEO2011. Ottawa, Ontario: Canadian Geotechnical Society.

@article{GEO11Paper366,author = Juan M. Mayoral; Miguel P. Romo; Francisco A. Flores ,title = Seismic response of bridges with cellular foundations built in soft clay,year = 2011}