Nonlinear analysis of 3-D steel frames

In this paper, a nonlinear analysis of three-dimensional steel frames is developed. This analysis accounts for material and geometric nonlinearities. The material nonlinearity considers the gradual yielding associated with member forces. The geometric nonlinearity includes the second-order effects associated with P-δ and P-Δ. The material nonlinearity at a section is considered using the concept of the P–M hinge consisting of many fibers. The geometric nonlinearity is considered by the use of stability functions. The modified incremental displacement method is used as the solution technique. The load–displacement relationships predicted by the proposed analysis compare well with those given by other approaches.