A general nonlinear analysis of concrete structures and comparison with frame tests

A computational technique is described for the general nonlinear analysis of large planar frames under static loading. The analysis accommodates both material and geometric sources of nonlinearity in a highly stable numerical procedure. For material behavior the moment-thrust-curvature relationships are reduced to polynomials made to represent common structural members. The nonlinear influence of axial shortening and P - Δ effects from displaced joints are accommodated by the analysis. Beam-column effects that magnify moments by the influence of axial force acting through deformed members can be approximated by introducing nodal points (or joints) at points of maximum deformation between the ends of members.Accuracy of the analytic procedure is demonstrated by comparing computed results with eight reinforced concrete frames tested at the University of Texas at Austin.