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.