1. Required building separations and observed seismic pounding on the soft soils of Mexico City.
- Author
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Tena-Colunga, Arturo and Sánchez-Ballinas, Daniel
- Subjects
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SOILS , *STRUCTURAL steel , *REINFORCED concrete , *GROUND motion , *STEEL buildings - Abstract
In this paper, the authors discuss the extensive structural pounding observed in Mexico City during the September 19, 2017 earthquake. A critical review of the recommendations available for required separations between adjacent buildings in the seismic codes of Mexico City since 1966 is offered. The reasons why these recommendations have not been effectively enforced since then are also addressed. A parametric study was conducted to understand better the structural pounding phenomena for strong ground motions which have been recorded in soft soils in Mexico City during the 1985 and 2017 earthquakes. For this purpose, equivalent frame models for existing reinforced concrete and structural steel flatslab buildings with nonlinear pounding contacts were used. Some well-known proposed equations for building separations were evaluated based upon the results of these parametric studies for pounding. The evaluated equations were the ABS, SRSS and DDC rules, as well as the absolute difference combination (ADC) rule proposed by the authors. From the obtained results, it was found that the minimum building separation between adjacent buildings established in the seismic code of Mexico City should be raised to avoid strong pounding on soft soils. Also, it was found that both the DDC and ADC rules are promising in defining building separations closer to the one obtained from dynamic simulations. These equations are less conservative than the version of the absolute sum rule currently established in Mexican seismic codes. • 98.9% of the observed pounding in Mexico City occurred in the soft soils gained to the former lakes. • The height difference between adjacent structures where more pounding was observed was ±4 stories. • Gap distances required to avoid pounding in the soft soils of Mexico City could be as large as 170 cm. • The minimum distance between adjacent structures to enforce for the soft soils of Mexico City should be raised to 15 cm. • The DDC and the ADC rules could be used with confidence to assess gap distances to avoid pounding in soft soils. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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