A Simplified Nonlinear Analysis Procedure Using Linear Analysis

Performing a typical Nonlinear Static Procedure requires the use of a nonlinear computer analysis program. Presently, computer program PERFORM 3D is most often used in structural engineering offices for this purpose. The concepts used in Nonlinear Static Procedure (NSP) are simple, and it would be desirable to develop an approach in which the results of linear analysis can be used to determine the nonlinear demands in different components of a building. This paper presents a procedure for using the demand capacity rations (DCR) obtained from a linear analysis to approximate component nonlinear demands. Two examples are presented to demonstrate the application of this process. One example is a one story shear wall building in which wall shear controls performance. The second example is a 15 story concrete shear wall building in which deformations in coupling beams and flexural yielding at the base of walls control performance.