Prediction of Scour Depth around Inclined Bridge Piers Using Optimized ANFIS with GA

Document Type: Research Paper

Authors

1 Assistant Professor, Department of Water Engineering, University of Guilan, Rasht, Iran

2 MSc Student of Islamic Azad University, Hormozgan branch, Iran

3 Assistant Professor, Department of Mechanical Eng, University of Guilan, Rasht, Iran

Abstract

Knowledge of the effective parameters and estimation of maximum scour depth around bridge piers has an important role in the safe design of bridges in rivers. With development of construction of structures, bridges with various geometries have been constructed such as inclined bridge piers group which has a complex scour process because of simultaneous effect of inclination of piers, foundation and sheltering of second piers. Therefore, most conventional approaches that are based on empirical method are unable to estimate scour dimension. One method to predict physical process whose effective parameters are related in a non-linear and complex manner is utilization of intelligent system. The aim of this research is to predict scour depth around the inclined bridge piers located on the rectangular foundation using optimized ANFIS parameters with GA, Matlab ANFIS and ANN with different hidden layers, activation function, and learning rules. Forty-eight sets of experimental data of scour around the inclined bridge piers were used for various flow condition foundation levels. To compare the results, R2 and RMSE were utilized. Analysis of results showed that Matlab ANFIS and ANN could predict the maximum scour depth with =0.976, RMSE=0.0530 and=0.99, RMSE=0.0359 at best configurations, respectively. Comparison of results indicated that optimization of ANFIS parameters improved the accuracy of prediction of desired parameters with=0.99, RMSE=0.0254.

Keywords