Determination of the causative mechanism of structural distress in the presidential palace of India

Abstract

Abstract The presidential palace of India was constructed between the years 1912 to 1929\u202fCE in a novel architectural style resulting from an amalgamation of Colonial and traditional Indian styles. During a visual inspection of this double-domed structure, meridional cracks were spotted in two out of the four niches in the drum of the lower dome. The observed distress raised two important issues that needed to be resolved- the cause of the cracks and their impact on the structural response. The uncertainty in the actual geometry of the building and the variety of materials used in its construction, the complex layout, lack of prior knowledge of reinforcement details and the undocumented changes made to the structure prompted the adoption of a multi-disciplinary scientific investigation to evaluate the structure. The methodical approach encompassed a literature review of dome failures in the past, historical and geometrical surveys, foundation inspection and the use of relevant non-destructive and minor destructive tests in the evaluation of the superstructure. The information gained from the aforementioned investigation was useful in the development of a 3D finite element model of the structure. The findings of the investigation revealed that owing to its geometry, tensile stresses develop in the unreinforced brick masonry drum. The reduction in the thickness of the drum at the locations of the niches results in an inherent weakness in the structure. The opening for the stairwell in the north-eastern corner of the building, at the level of the drum, further reduces the tensile resistance of the abutment system of the dome and gives rise to the observed crack pattern