Seismic soil classification using a new standard proposal and comparison with the current standard for sites located in Reñaca and Concón
DOI:
https://doi.org/10.4067/S0718-28132021000200030Keywords:
Seismic Soil Classification, Vs30, Soil fundamental periodAbstract
In Chile, to seismically classify a site where a structure is to be founded, the indications of the Chilean design code (NCh433 and DS61), have to be fulfilled. It is a requirement to have the average soil shear wave velocity of the upper 30 m of the site (Vs30), and laboratory or in-situ test results related with soil resistance such as: unconfined compression strength (qu), normalized standard penetration test resistance (N1) and/or soil undrained shear strength (Su). In the new classification proposal system (prNCh433, 2018), classification parameters are those that are related to seismic response at the ground surface of the site: Vs30, and the predominant soil period (Tg) estimated using the H/V spectral ratio (method of Nakamura). On this article it is compared the classification requirements of the Chilean standard with main design codes and standards in the rest of the world. Also, fundamental periods of soil obtained from measurements carried out in Reñaca and Concón area, are used to seismically classify sites where soil mechanics reports are available. The classifications are undertaken with the new proposed classification standard and comparisons are made with the current classification. As part of this work, it is analyzed whether the sites maintain or change their seismic soil classification and the type of change they undergo. Finally, soil parameters that are determinants for the obtained soil classifications are identified.
References
Aguirre, G. (2021). Microzonificación sísmica de las localidades de Reñaca y Concón mediante mediciones de espectro H/V Nakamura. Civil Engineer degree project (in development), Universidad Técnica Federico Santa María, Chile.
Chaudhary, M.T.A. (2018). A study on sensitivity of seismic site amplification factors to site conditions for bridges. Bulletin of the New Zealand Society for Earthquake Engineering 51(4), 197-211.
Chávez-García, F.J. y Montalva, G.A. (2014). Efectos de sitio para Ingenieros Geotécnicos, estudio del valle Parkway. Obras y Proyectos 16, 6-30.
DPWH (2013). LRFD bridge seismic design specifications. Department of Public Works and Highways DPWH guide specifications, Manila, Philippines.
DS61 (2011). Decreto supremo 61 que aprueba reglamento que fija el diseño sísmico de edificios y deroga decreto 117, de 2010. Ministerio de la Vivienda y Urbanismo, MINVU, Santiago, Chile.
Eurocode 8 (2004). Design of structures for earthquake resistance. Part 1: General rules, seismic actions rules for buildings. European Committee for Standardization, Brussels, Belgium.
Fernández, J., Pastén, C., Ruiz, S. y Leyton, F. (2017). Estudio de efectos de sitio en la Región de Coquimbo durante el terremoto de Illapel Mw 8.3 de 2015. Obras y Proyectos 21, 20-28.
Fukushima, Y., Bonilla, L.F., Scotti, O. and Douglas, J. (2007). Site classification using horizontal-to-vertical response spectral ratios and its impact when deriving empirical ground-motion prediction equations. Journal of Earthquake Engineering 11(5): 712-724.
GB 50011 (2010). Code for seismic design of building. Ministry of Housing and Urban-Rural Development MoHURD, National Standard of the People’s Republic of China, Beijing, China.
Godoy, C., González, L. y Sáez, E. (2015). Importancia de la velocidad de onda de corte y del período predominante para la evaluación de la respuesta de sitio en Santiago. Obras y Proyectos 17, 61-67.
IBC (2018). International building code. Chapter 16: Structural design. International Code Council. California, USA.
JRA (2012). Specification for highway bridges. Part V: seismic design. Japan Road Association, Tokyo, Japan.
Kouretzis, G.P., Masia, M.J. and Allen C. (2014). Structural design codes of Australia and New Zealand: seismic actions. Encyclopedia of Earthquake Engineering, Beer, M., Kougioumtzoglou, I., Patelli, E. and Au, I.K. (eds.), Springer, Berlin, Germany.
Lermo, J. and Chávez-García, F.J. (1994). Are microtremors useful in site response evaluation?. Bulletin of the Seismological Society of America 84(5), 1350-1364.
Leyton, F., Montalva, G. and Ramírez, P. (2012). A preliminary study of seismic microzonation of Concepción based on microtremors, geology and damages patterns. Obras y Proyectos 11, 40-46.
Mendoza, L., Ayala, F., Fuentes, B., Soto, V., Sáez, E., Yañez, G., Montalva, G., Ramírez, P., Gález, C., Sepúlveda, N., Lazo, I. y Ruiz, J. (2018). Estimación cuantitativa de la amenaza sísmica en base a métodos geofísicos: aplicación a las localidades costeras del segmento Los Vilos – San Antonio. X Congreso Chileno de Ingeniería Geotécnica, Valparaíso, Chile.
Nakamura, Y. (1989). A method for dynamic characteristics estimations of subsurface using microtremors on the ground surface. Q. Rep. Railway Tech. Res. Inst. Japan 30, 25-33.
prNCh433 (2018). Diseño sísmico de edificios. Comité de anteproyecto de norma.
NCh433 (2009). Diseño sísmico de edificios. Instituto Nacional de Normalización INN, Santiago, Chile.
NZS 1170.5 (2004). Structural design actions - Part 5: Earthquake design actions. New Zealand Standard. New Zealand.
Pastén, C., Lezana, F., Leyton, F. y Ruiz, S. (2015). Razones espectrales H/V de una red temporal de estaciones sismológicas en la Cuenca de Santiago – Resultados preliminares. Congreso Chileno de Sismología e Ingeniería Sísmica, Santiago, Chile.
Ruz, F. and Finn, W.D.L. (2019). New Chilean seismic code and the use of Nakamura period for assessing damage potential. 7th International Conference on Earthquake Geotechnical Engineering for Protection and Development of Environment and Constructions, Silvestri and Moraci (eds.), Associazione Geotecnica Italiana, Rome, Italy, CRC Press, 4760-4767.
SESAME (2004). Guidelines for the implementation of the H/V spectral ratio technique on ambient vibrations. Measurements, processing and interpretation. Site EffectS assessment using AMbient Excitations SESAME European Research Project, France.
Sucasaca, J. and Saez, E. (2021). Topographical and structuresoil-structure interaction effects on dynamic behavior of shearwall buildings on coastal scarp. Engineering Structures 247, 113113.
Verdugo, R., Ochoa-Cornejo, F., Gonzalez, J. and Valladares, G. (2019). Site effect and site classification in areas with large earthquakes. Soil Dynamics and Earthquake Engineering 126, 105071.
Verdugo, R. y Valladares, G. (2016). Análisis de registros chilenos y periodo predominante del sitio. IX Congreso Chileno de Ingeniería Geotécnica, Valdivia, Chile.
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