Title:
Rotational Stiffness of Concrete Slabs
Author(s):
Mehrdad Mehrain and Bijan Aalami
Publication:
Journal Proceedings
Volume:
71
Issue:
9
Appears on pages(s):
429-435
Keywords:
bending moments; building codes; columns
(supports); elastic analysis; finite difference theory; finite
element method; fiat concrete plates;
DOI:
10.14359/7093
Date:
9/1/1974
Abstract:
Using a finite element elastic plate analysis, lower and upper limits to the rotational stiffness of a flat slab at the column-slab junction are evaluated for a number of typical square slabs on a central column. The slabs represent unit panels of multiple-slab floors. The stiffnesses determined are presented in a graphical form and may be used in the equivalent-frame method in design of multiple square slabs. The results are comprehensive and effectively serve to clarify the picture of slab stiffness behavior. They also provide a useful basis for the accuracy assessment of the current approximate methods of stiffness evaluation. A comparison with the related recommendations of ACI 318-71 shows that the Code underestimates the slab stiffness for certain column-slab geometrics. The resulting lower bound solutions for slab stiffness and maximum moment coefficients closely agree with those previously available. A numerical example is given to illustrate the use of the data offered.