Indian Institute of Technology (IIT) Mandi researchers have developed a method to assess the earthquake resistance of buildings in the Himalayan region. According to the institute, the method is simple and allows decision-makers to prioritise any strengthening and repair work that must be done to improve the building’s earthquake resistance.
The study’s findings were published in the earthquake engineering bulletin. Dr. Sandip Kumar Saha, Assistant Professor, School of Civil and Environmental Engineering, IIT
Mandi, led the study, which was co-authored by his Ph.D. student Ms Yati Aggarwal.
Earthquakes cannot be reduced but damages can be
While earthquakes cannot be prevented, damages can be reduced by designing buildings and other infrastructure to withstand seismic events. The first step in ensuring existing structures’ earthquake safety is to assess their current vulnerabilities and strengths. A detailed seismic vulnerability assessment of every building is neither physically nor economically feasible. Building Rapid Visual Screening (RVS) is frequently used to assess building vulnerabilities on a large scale. RVS uses visual information to determine whether a building is safe to occupy or if immediate engineering work is required to improve earthquake safety.
Existing RVS methods are based on data from different countries and are not particularly applicable to the Indian Himalayan region due to some unique characteristics of the buildings in this region. The Himalayan region, for example, has many non-engineered structures (as with much of India). There is also haphazard infrastructure distribution and growth as a result of a lack of awareness among local construction workers and poor planning by stakeholders. It is therefore critical to use a region-specific RVS guideline that takes into account factors such as local construction practises, typology, and so on.
Method to screen reinforced concrete buildings
Dr Sandip Kumar Saha, said, “We have devised an effective method to screen reinforced concrete (RC) buildings in the Indian Himalayan region so that repair work may be prioritized according to the condition of the buildings and the risk from impending earthquakes can be minimized.”
Researchers have collected a large amount of data on the types of buildings present in the Mandi region of the Himalayas, as well as the typical attributes present in these buildings that are linked to their earthquake vulnerability, through extensive field surveys.
A numerical study was also conducted in order to develop guidelines for counting the number of stories in hilly buildings for RVS. Furthermore, an improved RVS method was proposed based on the vulnerable characteristics of buildings.
Developed screening methodology
The screening methodology developed is a simple single-page RVS form that does not require much expertise to fill out. It considers the various vulnerability characteristics that are unique to the buildings in the case study region.
Calculations made using these observations produce a seismic vulnerability score for buildings, which differentiates vulnerable buildings from the more robust ones, and allows better decision-making for maintenance and repair. The computation process is designed such that it minimizes the possibility of human bias or subjectivity of the assessor in scoring a building.
Ms. Yati Aggarwal, Ph.D. Scholar, IIT Mandi, said, “We have shown that the proposed method is useful for segregating reinforced concrete buildings in hilly regions according
to the damage that they are expected to experience in the event of an earthquake.”