The Earthquake Engineering Online Archive

Interactive computer analysis methods for predicting the inelastic cyclic behaviour of structural sections

Kaba, Said A.; Mahin, Stephen A.

UCB/EERC-83/18, Earthquake Engineering Research Center, University of California, Berkeley, 1983-07, 107 pages (515/K15/1983)

An interactive analysis program suited for microcomputers has been developed to analyze structural steel, reinforced concrete, and prestressed concrete sections subjected to axial load and uniaxial bending moments. The sections considered must have an axis of symmetry and the neutral axis must remain perpendicular to this axis. However, relatively general loading conditions, including load reversal, may be considered. Plane sections are assumed to remain plane during deformation. However, initial stresses and strains may be specified to account for prestressing, residual stresses, and sequential construction. The program currently includes bilinear, cubic, and Ramberg-Osgood steel models and a concrete model that can mimic ones suggested by Kent, Scott, Hognestad, Vallenas, Sheikh and Uzumeri, and others. The authors discuss the ease of implementing additional material models. The report discusses the theoretical background for the program, the solution strategies used and their limitations, and the types of analyses for which the program is suited. Various options can be used to develop moment-curvature and axial load-moment interaction curves. In addition, complicated loading histories, such as nonproportional application of axial load and moment including unloading and reversal, may be considered. The program is interactive in nature, permitting the user to rapidly redo a particular load increment or a complete load excursion starting from specified initial conditions, or to impose additional loading on the current state of the section. Input of section geometry and materials is also interactive and a user can modify parameters related to these items and reanalyze the section during the same or subsequent analysis sessions. Files are developed to store section and material properties as well as analysis results.

Available online: http://nisee.berkeley.edu/documents/EERC/EERC-83-18.pdf (4 MB)