Most houses not incorporated building bylaws: UN report
SHILLONG: Most of the houses in Shillong city have not incorporated building bylaws, and do not have adequate structural strength to withstand a large earthquake.
This was revealed in the report of United States Agency for International Development (USAID) and United Nations Development Programme (UNDP) on multi hazard risk and vulnerability assessment and risk atlas of Shillong.
The report said the most vulnerable are the masonry and RCC buildings.
The report was prepared with the support of Meghalaya government to develop resilient cities through risk deduction in the context of disaster and climate change.
In the 1897 Great Shillong earthquake, the city experienced huge damage to buildings. However, in the 1930 Dhubri earthquake, buildings in Shillong city suffered much lesser damage than expected due to the implementation of lessons learnt from 1897 earthquakes, the report added.
“This happened as a majority of the buildings rebuilt and constructed in those times were well-built timber houses (known as Assam type houses)”, the report said.
The physical vulnerability assessment has been carried out through literature survey, analysis of damage functions of different hazards on different structures, and by conducting
Rapid Visual Survey (RVS) of sample buildings covering residential, commercial, industrial, and critical facilities.
Three types of analysis were carried out to understand the impact of the natural calamity.
They are physical vulnerability analysis, social vulnerability assessment and environmental vulnerability analysis.
The physical vulnerability analysis in the city derives damage functions of key structural types, which are integrated in the risk assessment model.
“The RVS survey shows that there is a large number of masonry residential and commercial structures with poor maintenance that are vulnerable to earthquake hazard. The analysis shows that several buildings of different types need detailed structural analysis”, the report said.
With reference to RVS surveyed forms received from District Disaster Management Authority (DDMA) it has been observed that Christian Academy, Riatsamthiah, Woodland Hospital (Annex Block, New Block, Front Block and Rear Block), Children’s Hospital (Block A and B) and Supercare Hospital needed retrofitting based on their performance score.
For social vulnerability assessment, social indicator-based analysis has been carried out and a social vulnerability index at ward level has been developed.
In addition to this, a sample household survey was also conducted to understand household-
specific issues including livelihood vulnerability.
According to the report, the social vulnerability analysis shows that wards with slum pockets and wards where density of population is high, have a higher social vulnerability index. ) Interestingly, the population growth of the slums in the city showed a declining trend, the report said.
For environmental vulnerability analysis, the focus was given to assess the change in the built environment and green areas, which can be influenced by different hazards the city is exposed to, the report said.