Department of Civil Engineering, Indian Institute of Science Bangalore

Classification of Road Damage due to Earthquakes

New Intensity Scale for Road Damages due to Earthquake

Many cities of the world have suffered major economical and social setbacks due to earthquakes. Roads play an important role not only acting as a mere path to transport commuters, goods, and vehicles but also as a means to reach and rescue distressed people during emergencies like natural disasters and wars. Numerous studies have been conducted regarding the damage assessment, damage quantification, vulnerability, and risk analysis of structures. But very limited studies are carried out in vulnerability and risk analysis of road/transport networks. It is an accepted fact that, of all the modes of transport, road transport is the major means of transport to the people. Road system is a valuable asset of a city, and road network plays a vital role in emergency operations. Roads play an important role in post-earthquake scenario, i.e., to evacuate dead and injured people. If an evacuation plan is well organized, the number of dead and the distressed people can be significantly reduced. Hence, earthquake-induced road damage assessment and post-earthquake damage control studies are important for an effective disaster management plan. To assess the vulnerability, risk of transportation infrastructure, the road damage scale (RDS) plays an important role. At present, the modified Mercalli intensity (MMI) scale is a widely used damage quantification measure for seismic vulnerability of Transportation network. This MMI scale is a measure of earthquake intensity level based on damage caused to buildings by accounting site effects and induced effects. A significant point to be noted here is that the structural damage is well defined and quantified using MMI, but no specific reference is made for the damage of roads, even though they play a major role in post-earthquake relief operations (Tung 2004). History shows that major loss of life has been caused due to delay in timely assistance to earthquake victims. Thus, it becomes imperative to study the damage quantification of roads which will help in better disaster management. The importance of risk assessment of transport networks and summary of different methods are given in Kiremidjiam et al. (2007). The major component in the risk and vulnerability assessment of a transportation network is the damage measure (DM), which is basically the level or measure of damage for a given hazard. DM is used to estimate the severity of damage and thereby arrive at a damage ratio. So measure of road damage is important for the risk assessment of road network. Our study has made an attempt to propose a new damage scale for roads based on reported road damages, which will help to quantify the road damages due to earthquake. Summary of proposed correlations and discussion can be found in Anbazhagan et al (2012). Anbazhagan P Sushma Srinivas and Deepu Chandran (2012). Classification of Road Damage due to Earthquakes, Natural Hazard; 60: 425:460

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