Journal of Applied Sciences1812-56541812-5662Asian Network for Scientific Information10.3923/jas.2011.778.787ShahidzadehM.S.AmaniA.MotaghedS.52011115In this study FRP-hoop reinforcement relation in circular bridge piers is presented. The ultimate strain criterion is used to obtain an equivalent FRP thickness. Due to multi-parameter effects an explicit relation was not possible. This is then referred to as equivalent FRP thickness. Due to multi parameter effects Artificial Neural Networks (ANN) is used to solve the nonlinear problem. Finite Element Models that were calibrated by previous experimental data provide the input to ANNs. The outputs of ANNs presented reasonable results that were in agreement with real data. The results are displayed in graphs, which can be used to design or rehabilitate existing piers without ever needing to go through FRP codes’ design procedures.]]>Ahmad, S.H. and S.P. Shah,1982Monti, G., N. Nistico and S. Santini,2001Binici, B.,2007Solberg, K., N. Mashiko, J.B. Mander and R.P. Dhakal,2009Balmer, G.G.,1949Fardis, M.N. and H. Khalili,1981Hoshikuma, J., K. Kawashima, K. Nagaya and W. Taylor,1997Li, Y.F. and Y.Y. Sung,2004Mander, J.B., M.J.N. Priestley and R. Park,1988Mirmiran, A., K. Zagers and W. Yuan,2000Mirmiran, A. and M. Shahawy,1997Perera, R.,2006Richard, R.M. and B.J. Abbott,1975Richart, F.E., A. Brandtzaeg and R.L. Brown,1928Saadatmanesh, H., M.R. Ehsani and M.W. Li,1994Samaan, M., A. Mirmiran and M. Shahawy,1998