THE SEISMIC RESPONSE OF INELASTIC STRUCTURES

This study discusses the choice of suitable modelling procedures available in order for the engineer to commission on inelastic seismic analysis of his frame. The modelling of the stiffness and mass distribution were the first areas of concern. The stiffness method of analysis, using one-dimensional finite-elements, enabled a generalized formulation of the frame model to be achieved. The incorporation of a moment-axial load interaction capability for determining the failure of yield levels of a column is considered simple and necessary for all structures in which there are fluctuating axial loads. It has been shown that the shape of the moment-curvature hysteresis chosen may have a profound effect on the response of a dynamically excited single-degree of freedom system. Whichever moment-curvature function is chosen as being applicable to the frame under analysis, there still remains the major difficulty of satisfactorily tracking the relationship during a piece-wise integration. Great care must be exercised in the choosing of a suitable piece-wise scheme for the numerical integration of the kinematic equations. Explicit integration schemes need to be investigated as a way of eliminating the large amounts of computation necessary when the stiffness matrix is being reduced at each change of plasticity. "Ductility" has been found to be a very useful description if its use is left exclusively to that of describing the curvature at a section of a member. One of the most difficult problems facing the designer is that of deciding which earthquake accelerogram will best match the static loading conditions stipulated by the relevant building code of practice. The immediate future in the art of dynamic inelastic analysis lies in helping engineers to develop a qualitative understanding of the behavior of their already designed structures, so that they may expertly detail its load-resisting elements.

• Corporate Authors:

  National Roads Board, New Zealand

  Road Research Unit, P. O. Box 12-041
  Wellington,   New Zealand 
• Authors:
  • SHARPE, R D
• Publication Date: 1974

Media Info

• Features: Appendices; Figures; References; Tables;
• Pagination: 178 p.

Subject/Index Terms

• TRT Terms: Axial loads; Degrees of freedom; Ductility; Failure; Finite element method; Hysteresis; Inelastic stress; Kinematics; Mathematical models; Seismicity; Static loads; Stiffness
• Uncontrolled Terms: Inelastic action; Models; Seismic response
• Old TRIS Terms: Finite elements
• Subject Areas: Bridges and other structures; Highways;

Filing Info

• Accession Number: 00174413
• Record Type: Publication
• Report/Paper Numbers: RRU Bulletin No. 37
• Files: TRIS, ATRI
• Created Date: Jun 14 1978 12:00AM