Structural Analysis of Historical Constructions, New Delhi 2006 P.B. Lourenço, P. Roca, C. Modena, S. Agrawal (Eds.) 1 INTRODUCTION The damage suffered by tall and flexible towers in the Kutch area of Gujarat in the 2001 earth- quake had drawn attention to the seismic behaviour of Qutb Minar, one of the tallest stone ma- sonry towers in the world. This 12 th century architectural marvel is an important landmark of Delhi, the capital city of India. Delhi region falls in seismic zone IV in the seismic zone map of India. The zone has fairly high seismicity with a general occurrence of earthquake of 5-6, a few of magnitude 6-7 and occasional incidence of 7.5-8 magnitude shocks. Among these incidents the 1803 Gharwal-Kumaon earthquake had brought down the crowning cupola of the Minar and left the Minar seriously damaged. The seismic history of the city reveals the seismic threat on this world heritage monument and calls for the vulnerability assessment of the structure. In this background the paper reports the seismic vulnerability assessment of the structure including the hazard assessment at the site, the numerical modelling of the structure and the dynamic response spectrum analysis of the structure. 2 QUTB MINAR The construction of the Minar started in 1198 AD and attained its present status in 1368AD through three phases. In plan the minar is circular, the base being 14.07 m in diameter and it ta- pers to a diameter of 3m at the summit along a height of 72.45m. Fig. 1 shows the sectional ele- vation and plan of the minar at each storey level. It consists of an externally fluted shell and an inner shaft, which supports a spiral stairway of Delhi quartzite stones. In its artistic aspect the most elegant features of the Minar are the balconies supported by a system of stalactite bracket- ing. The Minar shell masonry consists of a thick rubble stone masonry infill faced externally with ashlars of red sandstone and internally with Delhi quartzite stone. The central shaft is of rubble stone masonry with quartzite stone facing. The foundation is 10.2m deep and was strengthened by cement grouting during 1971-1972 on observing a tilt in the verticality of the Minar. Seismic Vulnerability Assessment of Qutb Minar, India Sreeja Chandran, A. Meher Prasad and M.S. Mathews Indian Institute of Technology, Department of Civil Engineering, Chennai, India ABSTRACT: This study addresses the Seismic vulnerability of Qutb Minar, the tallest Minaret in the world. The seismic vulnerability assessment of the structure is explained in terms of the hazard assessment at the site, numerical modelling, site response analysis, and dynamic re- sponse spectrum analysis of the structure. Finally the results are discussed in terms of thrust lines and principle stress contours.