s.sh Hashemi - Civil Engineering Department, Persian Gulf University, Bushehr, Iran
m Vaghefi - Civil Engineering Department, Persian Gulf University, Bushehr, Iran

In this paper, the nonlinear behavior of reinforced concrete column with consideration of bondslip effect between the bars and surrounding concrete is investigated. Separate degrees of freedom are used for the steel and concrete parts in nonlinear modeling of the reinforced concrete elements. Moreover, the complicated formulation in finite element domain is abstained. The formulation of the elements is derived based on displacement method and principle of stationary potential energy. After validation of the method through the comparison of numerical and experimental results, the effect of bond-slip on the analytical strength capacityof reinforced concrete column which is affected by axial and bending forces is investigated. The axial force–bending moment (P-M) interaction curve of the reinforced concrete column for two condition of with and without bar slip effect is calculated and compared by using the analytical results. Also a comparison is carried out between the results and ACI recommended curve. Results show that bond-slip effect has more affects on the ductility and no considerable effect on the strength capacity and P-M interaction curve of the RC section. Although the ACI318-05 suggestion have made based on perfect bond assumption, but does not need modification for the sake of bond-slip effect and even ensure and conservative is also.

bond-slip effect, P-M interaction curve, reinforced concrete column, seismic analysis, column capacity