Structural Analysis of Historical Constructions, New Delhi 2006 P.B. Lourenço, P. Roca, C. Modena, S. Agrawal (Eds.) 1 INTRODUCTION The Taj Mahal monument is the most important Archaeological survey of India monument in India. It is essentially a double domical structure supported on eight massive columns with arches spanning between these columns. The entire structure rests on 33.5 m thick raft with about 18.3 m thickness of the raft above the ground level. The raft rests on a thin sandy layer of 9.1 m thickness, followed by a 63.4 m thick clayey strata underlain by rock. The entire super- structure and the raft are built in brick masonry consisting of 3.8 cm thick fire burnt clay bricks and mortar joints of varying thickness upto as much as two inches. The geometry of the monu- ment is very complex indeed. The exact dimensions of the monument and the sub-structure are unknown and were obtained from the data supplied by Archaeological survey of India, New Delhi. The analysis was necessitated due to the proposal of creating an artificial reservoir by constructing a weir across the river Yamuna behind the Taj structure. The Taj Monument has been analysed by Finite Element Method (FEM) (Zienkiewicz 1971) as a three dimensional solid continuum using two types of solid elements namely 20 Noded Hexahedral elements and 15 noded Triangular prisms. The monument has been analysed for vertical loads only. The analysis for wind loads has not been considered necessary, as the monument is extremely stable because of its gigantic dimensions and its location in a zone of moderate wind velocities. The bore-hole observations have indicated a water table level which submerges all the sandy and clayey soil strata beneath the monument. The elastic constants of the masonry used in the construction were obtained using chunks of masonry taken from the ru- ins of contemporary structures across the river Yamuna and those of the soil, using the undis- turbed soil samples extracted during the borings. 2 SUPER ELEMENT STRUCTURAL ANALYSIS MODULE (SESAM) SESAM is a large, general purpose Computer Software based on the finite element analysis. It contains super-element capabilities for the modeling of the structure and uses substructure tech- nique for the analysis of large and complex structures. It has a very powerful interactive pre- Three-Dimensional Finite Element Analysis of M.N. Viladkar, N.M. Bhandari Indian Institute of Technology Roorkee, Department of Civil Engineering, Roorkee-247667, India P.N. Godbole VNIT Nagpur, Department of Applied Mechanics, Nagpur-440010, India D.N. Trikha Indian Institute of Technology Roorkee, Department of Civil Engineering, Roorkee-247667, India ABSTRACT: The paper involves 3-D finite element modeling and analysis of the famous Taj Mahal structure using standard commercial package- SESAM (Super Element Structural Analy- sis Module). The stresses have been found to be small compared to the compressive strength of masonry giving a factor of safety of the order of 4 to 8. The vertical stresses in the columns are primarily compressive with indications of small zones of insignificant tensile stresses on one of the faces. Further, under vertical loads, displacements of domical portion and floor system are almost uniform, while the substructure deforms in natural bowl shape. Taj Mahal Structure