Title:
Design Indications From Tests of Un
Braced Multipanel Concrete Frames
Author(s):
J. S. Ford, D. C. Chang, and J. E. Breen
Publication:
Concrete International
Volume:
3
Issue:
3
Appears on pages(s):
37-47
Keywords:
axial loads; bending moments; building
codes; columns (supports); diaphragms (concrete),
ductility; frames; long columns; reinforced concrete:
DOI:
Date:
3/1/1981
Abstract:
This paper summarizes the design recommendations and suggested ACI Building Code changes stemming from studies of reinforced concrete columns in multipanel frames and a complementary study of isolated columns under controlled lateral deformation loading. The study supports a liberalization of the limiting strain criterion for column design which would permit efficient utilization of higher strength reinforce. ment and may provide significant design and economic opportunities. The studies also provide a basis for improved computer analysis of complex rein.forced concrete frames. Improved procedures for computing moment-curvature relationships for concrete columns and for incorporating such techniques into a nonlinear matrix analysis are suggested. The curvature relationships reflect the considerable duc tility noted in the tests. Multipanel frame studies clarified the nature of columns and frame stability failures and verified the concept of using story moment magnification in unbraced frames. Desirable changes in the moment magnification procedures are suggested to clarify the application to unbraced frames, and will have important implications on the design of unbraced structures subject to combined gravity and lateral loads. [Authors]