Performance Evaluation of Gravity Type Retaining Wall Under Earthquake Load: Fid-Bau Portal

Performance Evaluation of Gravity Type Retaining Wall Under Earthquake Load

Chowdhury, Indrajit / Singh, Jitendra Pratap

Abstract Gravity retaining walls, especially with improvement of RCC structures though have become more or less obsolete in terms of construction (replaced by RCC cantilever and counter fort type retaining walls), yet in India, there exists a number of them that has been built in the past in many strategically important places (both post and pre independence). Evaluating their health in terms of a future strong motion earthquake remains an important exercise—now that our understanding of this fury of mother nature is far more profound. Unfortunately tools available to assess its behavior as realistically as possible under seismic force even today is quite limited, marred by idealization, that are unrealistic and may not reflect correctly the actual behavior in reality, and this needs a serious evaluation. In Indian context, the only tool available to assess a gravity type retaining wall’s performance is by Mononobe and Okabe Method (M–O method), that continue to dominate IS code, notwithstanding the fact that many countries including US has now abandoned the method, as it has now been proved beyond any dispute that M–O method gives a lower bound solution than reality. Present paper tries to address some of these shortcomings as proposed above and come up with a mathematical model that is more realistic, and which may be used for performance evaluation of such gravity retaining walls under future earthquakes. Finally, the paper suggests some practical strengthening measure that may be undertaken to enhance these walls performance—where to the author’s perception if re-evaluated, many of them would be found unsafe in context to present earthquake code.