[month] [year]

17SEE

December 2022

Dr. P Pravin Kumar Venkat Rao and and his M.Tech student, Rohan Vashisht participated and presented 3 papers focussing on the seismic safety of stone masonry buildings in India at the 17th Symposium on Earthquake Engineering (17SEE), a quadrennial event organized by the Department of Earthquake Engineering, Indian Institute of Technology Roorkee (IITR)  from 14  to 17 November. 

 

  • Seismic Performance of Different Typologies of Stone Masonry Houses in India

 

Research work as explained by Dr. P Pravin Kumar Venkat Rao and Rohan Vashisht:

World over, stone has been extensively used as a building construction material due to its local availability and high durability. The scenario for the construction of buildings in India is no more different than compared to other parts of the world. According to the 2011 Census of India, 43.48 million houses (~14% of the total number of houses) have stone as the predominant wall material. Owing to the fact of non-engineered construction, wide variations in terms of stone masonry construction can be seen in the Indian subcontinent, particularly in the Himalayan belt. In this study, a field survey is conducted to identify the seismic resistant features in traditional building practices which make use of stone for construction, e.g., Thathara construction, Dry-stone construction, Koti Banal construction, etc. The percentage of these types of structures is decreasing due to an increase in urbanization, increasing housing demands, non-availability of traditional construction materials and skilled artesian for building new structures as well as costly repair and retrofitting techniques for damaged and existing structures. Thus, there is a dire need to safeguard these structures as if this trend continues, these buildings will become things of the past. In this paper, a review of structural configuration, roofing systems, foundation type and potential failure modes of these construction typologies are studied, and the effect of different retrofitting techniques that exist in the construction type on their expected seismic performance is discussed.

 

 

  • Seismic Retrofitting of Existing Stone Masonry Houses: An Overview

Research work as explained by Dr. P Pravin Kumar Venkat Rao and Rohan Vashisht:

Recurrent earthquakes in the past two decades have taken thousands of lives (e.g., the Kashmir earthquake killed some 80,000 people) and destroyed millions of homes and other buildings. This colossal loss of lives was not because of the earthquake but because people were inside buildings (e.g., stone masonry structures) that were highly vulnerable. Had these buildings been retrofitted with a small fraction of the cost of reconstruction, the death count would have been much smaller. The past earthquakes have brought out many weaknesses in masonry design and construction practices as these structures behaved unsatisfactorily and sustained major damage. Hence, the safety and retrofitting of existing stone masonry houses are very important. Considerable research work has been directed towards evolving suitable methods of earthquake resistance in stone masonry houses, but despite the availability of such methods, masonry buildings have been damaged in the event of earthquakes, because of the following reasons: (i) lack of awareness, formal training and technical knowledge in earthquake-resistant construction; (ii) lack of concern about seismic safety because of the in-frequent occurrence of earthquakes; (iii) people lack financial resources to meet the earthquake-resistant requirement; and (iv) despite the availability of provisions and recommendations of earthquake-resistant measures to be applied on stone masonry buildings in the form of various codes, these are rarely being implementation in actual practice. Therefore, in the present study, an overview is presented about how the retrofitting of existing stone masonry houses using different techniques can be implemented to reduce their seismic vulnerability and loss of life.

 

 

  • A Review of Seismic Safety Measures for the Construction of New Stone Masonry Houses

 

Research work as explained by Dr. P Pravin Kumar Venkat Rao and Rohan Vashisht:

Stone masonry walls have inherent weaknesses against the lateral forces of an earthquake. These weaknesses result in inadequate performance during earthquakes. Mistakes are commonly committed in the construction of stone walls, especially in the random rubble-type masonry. These mistakes further erode strength. When shaken, poorly constructed walls having inadequate interlocking between the inside and the outside faces (wythes), the faces begin to separate, resulting in rapid weakening of the wall and leading to the collapse of one or both wythes. In the presence of excessive openings, the wall becomes weak against the tearing action caused by the earthquake forces that are parallel to the length of the wall. This results in diagonal cracking of varying severity in the walls. Further, due to poor connection between the walls and the floor/roof, it results in failure of the floor diaphragm and affects the overall stability of the structure. Hence, while choosing to construct a building with stone masonry, the owner must make sure that the measures required to counter these weaknesses are taken during the construction so that in the event of a potentially destructive earthquake, the structure can withstand its impact without suffering much damage. Therefore, in the present study, an overview is presented for different failure modes of stone masonry houses, seismic safety provisions for the new construction considering the regulations for the wall, floor/roof construction, and the provision of horizontal and vertical reinforcement to ensure good seismic performance against the future earthquakes.