Jesús Pacheco-Martínez

Application of InSAR and Gravimetry for Land Subsidence Hazard Zoning in Aguascalientes, Mexico

In this work we present an application of InSAR and gravimetric surveys for risk management related to land subsidence and surface ground faulting generation. A subsidence velocity map derived from the 2007–2011 ALOS SAR imagery and a sediment thicknesses map obtained from the inversion of gravimetric data were integrated with a surface fault map to produce a subsidence hazard zoning in the city of Aguascalientes, Mexico. The resulting zoning is presented together with specific recommendations about geotechnical studies needed for further evaluation of surface faulting in these hazard zones. The derived zoning map consists in four zones including null hazard (stable terrain without subsidence), low hazard (areas prone to subsidence), medium hazard (zones with subsidence) and high hazard (zones with surface faulting). InSAR results displayed subsidence LOS velocities up to 10 cm/year and two subsidence areas unknown before this study. Gravimetric results revealed that the thicker sediment sequence is located toward north of Aguascalientes City reaching up to 600 m in thickness, which correspond to a high subsidence LOS velocity zone (up to 6 cm/year).

In situ and nondestructive characterization of mechanical properties of heritage stone masonry

The necessity of conserving and preserving the heritage is nowadays a developing study line for several researchers. From a civil engineering perspective, one of the most important issues for the conservation of historical buildings is to ensure the structural stability. For this purpose, it is necessary to determine the mechanical properties of the ancient construction materials. However, these structures cannot be evaluated by destructive tests due to politics and restrictions for preserving the heritage built. As a consequence, new methods that do not put in risk the integrity of the materials and the structure are becoming useful tools for researchers who work on structural engineering of heritage buildings. This paper presents a nondestructive method (NDM) that has been used to characterize the mechanical properties of different constructive systems of the San Antonio de Padua Temple, which is a religious icon in Aguascalientes, Mexico. This method includes the measuring of seismic waves’ travel time in order to obtain shear and compressional velocity waves. Results show that with this method mechanical properties of masonry can be obtained such as Young’s modulus, Poisson ratio and bulk density, which are needed for the structural analysis using numerical simulation models.

Deterioro de las rocas en los muros de mampostería de la Catedral de Aguascalientes, México

Se utilizaron tobas volcanicas de alta porosidad para construir los muros de mamposteria de la Catedral de la ciudad de Aguascalientes, en el centro de mexico. En la actualidad, la mamposteria de piedra muestra evidencias de deterioro, principalmente en la parte inferior de las paredes exteriores debido al efecto de la humedad y la contaminacion ambiental que esta causando danos tales como microdescamacion, descamacion y patina. Se realizaron estudios petrologicos que incluyeron difractometria de rayos X y analisis petrofisico como determinaciones de porosidad, densidad y densidad aperente, asi como un levantamiento de danos de piedra para obtener informacion sobre los tipos de rocas utilizados para elaborar los muros de mamposteria, sus caracteristicas petrologicas y danos fisicos. No se desarrollaron pruebas compresionales debido a la falta de muestras de piedra pero hay datos reportados para estas piedras por otros autores. Los resultados permiten identificar el tipo de piedra mas propenso a deteriorarse, el mecanismo de deterioro de la piedra, y los factores que aceleran el deterioro. Aunque los resultados tienen un uso pragmatico para las obras de restauracion de la Catedral de la ciudad de Aguascalientes, la metodologia aplicada podria ser utilizada para determinar la vulnerabilidad de las rocas a deteriorarse en edificios patrimoniales en cualquier lugar del exterior

Characterization of the Mechanical Properties of Ancient Masonry from a Non-destructive Method In Situ

This paper presents a methodology for determining the mechanical properties of the masonry elements by mean of seismic techniques and how these are included in a numerical model of a case study of a building. This work presents partial results of a research in process of doctoral thesis. It is part of the line of Non-Destructive Test (NDT) in situ that uses the measuring of seismic waves travel time to obtain shear and compressional waves; with these parameters it is possible to obtain the mechanical properties of the masonry of ancient buildings as Young’s Module, Poisson Ratio and density. The obtained data comes from a case study, the Temple of San Antonio de Padua, located in Aguascalientes, Mexico. In addition, a numerical model developed in SAP2000 is presented with the characterized properties obtained from the analysis. Results of this research will contribute future numerical analysis because it will be possible to obtain the values of each part of the building, and in this way, offer more reliable information about the behavior of the building.