Unsymmetrically Reinforced Concrete Columns Under Small Eccentricity of Loading
Unsymmetrically Reinforced Concrete Columns Under Small Eccentricity of Loading
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Date
1991-05
Authors
Valentine, Eziefule Ezetah
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Abstract
Reinforced concrete columns under Small
Eccentricity of loading have not been given adequate
attention as a class of columns which require its own
design method. The present assumption is that current
theories on columns which regard eccentricity as a
purely flexural parameter, are adequate for the design
of this class of columns. The result is that columns
under small eccentricity are either designed as flexural
systems or as axially loaded systems with arbitrary
reduction of the assumed material strengths. Available
design charts for uniaxially and biaxially loaded
columns have limited parameters as well as assume
symmetrical arrangement of reinforcements which make
their use for the design of this class of columns
uneconomical.
New models for design and capacity estimation of
uniaxially and biaxially loaded columns have been
proposed. The models indicate lower reinforcement
requirement and more flelxible use of design parameters,
over existing methods. A total of seventy-two replica
model and prototype columns were crushed to failure as
well as a model frame, to test the assumptions of the
propoised design and capacity estimation methods. The
recorded failure loads were compared to both the
proposed theoretical loads and current theories of load
estimation. The results show that the proposed load
capacity estimation model is more realistic in
determining the load capacity of unsymmetrically
reinforced concrete short columns. With a hundred
percent agreement between expected and recorded failure
loads, the assumptions of the proposed design/load
capacity estimation methods are fairly accurate. The
proposed methods simplify the design problems of
unsymmetrically reinforced concrete short columns under
small eccentricity of loading.
Description
A Dissertation Submitted to The Postgraduate School,
Ahmadu Bello University, In Fulfillment For The
Requirements For The Degree of Ph.D (Structures)
Department of Civil Engineering
Faculty of Engineering
Ahmadu Bello University, Zaria
May, 1991
Keywords
Unsymmetrically,, Reinforced,, Eccentricity,, Loading