Experimental Study On Buckling Capacity Of Slender Steel Reinforced Concrete Columns Subjected To Eccentric Load

The structures of steel reinforced concrete have both the steel structure and the concrete structure's advantages, large numbers of experiments show that this kind of structure can greatly improve the bearing capacity and the resisting seismic property, so the section size decreased greatly, But it is noticed that the section size decrease leads to the slenderness ratio increase, so stability problems of long column can not be neglected. Because the test information of long columns is seldom, so, based on experiments, this paper carefully studied the stability bearing capacity of slender steel reinforced concrete columns with eccentricity for offering the test and theory analysis of correlative construction.The major works of this paper are as follows:1. According to the experiment study of six compressed specimens with large eccentricity, and quote the former scholars'experiments, and contrast steel reinforced concrete column with axial load ,small eccentricity and large eccentricity load, the following problems of slender steel reinforced concrete columns are discussed, including the relationship between load and deflection, distribution regulation of deflection along the column, mechanical properties of the steel skeleton and concrete, the relationship between load and vertical distortion, the failure state of specimens, moreover demonstrates the supposition of plain section, etc.2. According to the experiment, the N-M curves of steel reinforced concrete columns are discussed.3. Based on the result of experiment and loading condition of column, a calculating model of this column is determined, the loading-deflection whole process of steel reinforced concrete eccentricity compression long columns is calculated. The influence of material nonlinearity, geometric nonlinearity , initial eccentricity are considered. The theory calculation results agree with those of tests satisfactorily. Based on this, the stability bearing capacity's changing of steel reinforced concrete long columns was studied by changing slenderness ratio, the strength grade of concrete and the eccentricity.4. According to the formers'experiments and this paper's experiment, the flexural stiffness of steel reinforced concrete column with eccentricity and its calculate method is analysed, also edit the coefficient of the rigidity calculate formulas. Based on the above, it is concluded that the eccentric ratio of slender steel reinforced concrete columns with eccentricity should be controlled within 0.5, and its slenderness ratio should not exceed 20. When the slenderness ratio remains unchanging, the stiffness is decreased with the eccentricity increase; when the eccentricity remains constant, the stiffness is increased with the slenderness ratio increase.