Structural Assessment of the Seismic Behavior of the Dome of the Taj Mahal

Abstract

This paper presents the results of a study of the structural assessment of the seismic behavior of the main dome of the Taj Mahal, in Agra, India. Built by the Moghul emperor Shah Jahan between 1632 – 1648 AD, the structure is one of most famous buildings in the world and the finest and most sophisticated symbol of Moghul architecture in India. As it is located in a zone of moderate seismicity, there is an urgent need for ensuring the structural safety and preservation of this iconic cultural heritage for future generations. The objective of this study is to develop a simplified approach to enhance our conceptual understanding of the mechanism of load path/transfer in the dome of the Taj Mahal under both gravity and seismic loads, as well as to better understand the influence of the geometry of the dome on its structural behavior. Using the software SAP2000, a finite element model of the dome is created and analyzed under the action of gravity and seismic loads, with the seismic loading assumed to have a PGA of 0.25g based on the results of a study conducted by the Indian National Disaster Management Authority. The results obtained include plots of the distribution of nodal reactions at selected levels to represent the lateral load behavior of the dome of the Taj, as well as plots illustrating the paths of load transfer under the action of gravity and seismic loads. Free body diagrams of selected rings are also presented to illustrate the ‘hoop’ forces in the dome, while simplified internal stresses are computed and compared with known material properties. Observations are also presented about the effect of the dome geometry, especially the bulging part of the dome, on the distribution of reactions and the resulting mechanism of load transfer in the structure under both gravity and seismic loading.

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