STRUCTURAL ANALYSiS OF HISTORICAL CONSTRUCTIONS

Abstract

As advances are made in earthquake engineering and more and more resilient and earthquake - resistant structures are being designed and codes of practice are being revised a great amount of attention needs to be paid to the historical structures. Studies pertaining to earthquakes began only around the 17 th century and those related to their effects on structures began even later in the 19 century. Hence structures made during or prior to this period are often not designed for seismic forces. India has many heritage structures that were constructed long before the codes for seismic resistant design came in practice and, in many regions the seismic activities too have changed over time. It is therefore necessary that these monuments are analyzed for safety during seismic activity. Most historical structures are made up of stone or brick and various types of mortar. Dams constructed before introduction of IS codes generally did not include design for uplift and seismic loads. Materials used in construction were often locally available stones and lime surkhi. Obtaining material properties remains a challenge as the present condition of the material is difficult to ascertain. This study aims to analyze such a darn and identify likely failure of material and where this failure would begin. The darn studied here is 120 years old and is composed of multiple materials with strengthening measures undertaken over time. 2D modelling and analysis was done using ANSYS 14.0. Static analysis and eight dynamic analysis were perfornied, three linear time history analysis and five non linear time history analysis to estimate probable failure of materials within the dam. Two cases, one for effect increased seismic activity represented by increased PGA values and second for effect of decreased material strength has been considered. The most likely failure patterns for both cases have been obtained