A variable layering system for nonlinear analysis of reinforced concrete plane frames

An improved method has been developed for the computation of the section forces and<br />stiffness in nonlinear finite element analysis of RC plane frames. The need for a new approach arises<br />because the conventional technique may have a questionable level of efficiency if a large number of<br />layers is specified and a questionable level of accuracy if a smaller number is used. The proposed<br />technique is based on automatically dividing the section into zones of similar state of stress and tangent<br />modulus and then numerically integrating within each zone to evaluate the sectional stiffness parameters<br />and forces. In the new system, the size, number and location of the layers vary with the state of the<br />strains in the cross section. The proposed method shows a significant improvement in time requirement<br />and accuracy in comparison with the conventional layered approach. The computer program based on the<br />new technique has been used successfully to predict the experimental load-deflection response of a RC<br />frame and good agreement with test and other numerical results have been obtained.