Impact of Vibrations on a High Rise RCC Structure Due to Blast Induced Demolition of Adjacent Building

The demolition of high rise structures is a very challenging task especially in urban areas. Controlled explosion using delayed detonation techniques can be used effectively for demolition of high rise structures to reduce the time required and for cost control. The technology was successfully used for the demolition of five high rise structures situated in Maradu municipality, Cochin for violating the costal regulation zone norms in January 2020. Vibration generated during the demolition process was studied by the team of IIT Chennai by instrumentation at strategic locations, and an attenuation relationship was formulated to infer damage potential of surrounding buildings. Among the structures demolished was 17 storeyed Golden Kayaloram apartment which was just 10 m away from 20 storeyed Heera Windfaire apartments. It was apprehended that the blast induced vibration will induce considerable damages on the adjacent structure. Based on the site specific acceleration measured at the property of Heera apartments the blast induced impact on the structure was analysed using STAAD PRO V8i and is compared with dead load, live load and earthquake load combinations. From the studies carried out it can be concluded that the forces induced due to the blast induced vibration is lesser than the earthquake forces and since the structure was designed for taking care of earthquake forces, the building was capable to withstand blast induced loading without any damages other than minor cracks due to impact of flying debris.