Seismic disaster resilience by improving infrastructure strength in active seismotectonic zones of Sikkim Himalaya, India—An integrated in-situ and laboratory based approach

United Nations SDGs-11 focuses on safe, resilient, sustainable cities and human settlement. Importance given to implement the Disaster Risk Reduction strategy where the number of death and economic loss to be reduced. Seismic disaster risk reduction is one of the major task in SDGs., The occurrence of earthquake in the Himalayan region is continuous and infrastructures are highly affected. The study aims to suggest a suitable seismic retrofitting technique for infrastructures in Sikkim Himalayan region by In-situ and laboratory based analysis. In the lab environment, geoinformatic based geospatial databases have been generated to understand the seismological characteristics of the study area and a seismic retrofitting experiment has been conducted with the help of plaster of Paris column wrapping with glass fiber to test the strengthening of the column specimen. Also, In-situ field observation data has been collected and analyzed to recognize the vulnerable infrastructures which have the probability to get damaged during an earthquake and relevant seismic retrofitting technique has been suggested for vulnerable infrastructures by incorporating with lab based structural analysis. The experimental result shows that the first crack is developed in the Specimen-I without wrapping while the applied load is 320N, deflectometer reading is 555 mm. At a load of 640N, the column developed crack. The complete failure of the column has also been recognized from this specimen while the applied load is 832N and deflectometer reading is 924 mm. In the fiber wrapped specimen (Specimen- II), it is observed that the crack is not developed in the specimen-II column till it has been completely uprooted from the base when the load reached 320N the corresponding deflection was found to be 350 mm which is very much less than Specimen I. The experimental result indicates that the glass fiber wrapped specimen appears stronger with an increasing load than without wrapped specimen. It can be inferred that the seismic retrofitting technique using GFRP wrap in concrete structure can improve the strength of the buildings in the study region. The proposed technique is suggested for different concrete infrastructures in the study region to improve the strength of the columns and beams for protecting infrastructures.