Analysis of century old masonry tower of indo-sarascenic style: visual inspection, NDT and FEM

Abstract

This study investigates assessing the structural behaviour and efficacy of historical masonry towers constructed using unreinforced masonry techniques. Four such towers were subjected to numerical analysis through the finite element method (FEM) in the aftermath of the 2015 Nepal earthquake. The initial stages involved visual inspections to gauge the towers' structural conditions. Using these visual assessments and data from existing records, precise geometrical plans and elevations for each tower were incorporated into AutoCAD. Subsequently, comprehensive 3D-models of the towers were subjected to complex analysis containing static and dynamic assessments. Employing the ANSYS Workbench tool (version-14) with Indian codal provisions and guidelines (IS:875, Part I-III) offered a distinct insight into the study. Material properties of the towers are accomplished through non-destructive testing (NDT), incorporating Rebound Hammer and Ultrasonic Pulse velocity methods. Site visual inspections unveiled significant damage to integral tower components such as arches, openings, and masonry walls. This observation highlights susceptibility to abrupt structural elements and material failures. Furthermore, utilising NDT data as a computational input stimulated insights into the substantial influence of tower geometry—encircling factors like slenderness, wall thickness, and openings-on structural capacity regarding stresses, deformations, and overall performance. The research highlighting vulnerabilities and structural complexities extends to suggesting mitigation strategies, notably retrofitting, that can preserve these valuable remains of history.