Structural Monitoring of the Mexico City Cathedral (1990–2014)

ABSTRACT

The Mexico City Cathedral underwent major rehabilitation during the 1990s to mitigate the effect of extreme differential settlement. As part of a comprehensive program, the project undertook a partial correction of existing differential settlements and remedial interventions to prevent additional settlement and improve the structural safety of the building. Monitoring the response of the structure during and after the rehabilitation was an essential component of the program because it enabled adjustments to the actions that were being undertaken in the subsoil and the foundation. Subsequently, this assessment was the basis for the detection of any sign of inappropriate structural performance.

This article provides a brief description of the entire project and the effect of the various stages of rehabilitation on the patterns of differential settlement and the structural response of the building. It also describes the monitoring systems and evaluates their results, especially the results obtained 14 years after the completion of the rehabilitation program. Particular emphasis is placed on the results of the seismic network, which has provided a substantial amount of valuable information about the peculiar characteristics of the seismic input and the dynamic response of the structure.

The findings conclude that the mitigating measures have significantly prolonged the life expectancy of the building and achieved a significant reduction of the growth rate of its differential settlements. However, continuous monitoring is essential for the detection of early signs of changes in the patterns of subsidence or the structural response to the building.

KEYWORDS:

• historical buildings
• monitoring structural health
• seismic response
• structural rehabilitation
• subsidence effects

Acknowledgement

The General Directorate of Monuments and Sites, which is a branch of the National Council for Culture and the Arts, conducted the rehabilitation program of the Cathedral under the direction of Sergio Zaldívar until 2000 and under the direction of Xavier Cortés-Rocha after 2000. Enrique Tamez and Enrique Santoyo devised and executed the interventions in the subsoil with the assistance of TGC engineering company.