중심축하중을 받는 구속PC기둥의 극한강도해석 = ULTIMATE STRENGTH ANALYSIS OF RESTRAIND PC COLUMNS UNDER CONCENTRIC LOAD

다국어 초록 (Multilingual Abstract)

One of the most important elements of any structural frame is the column. This element is usually under the action of combined axial load and bending moment. Columns with small slenderness ratios are usually analysed by simple consideration of the equilibrium of forces and compatibility fo strains. On the other hand, for columns with large slenderness ratios, the compound effect of the axial load and column deflection adds to the column bending moment, thus reducing of the column ultimate capacity.
In this study, the analytical methodqr for the ultimate strength analysis of prestressed concrete columns under concentric load is developed, including the material and geometrical nonlinearties and the nonliner behavior of reatrained ends of a column in a frame.
To construct a maternetical model of the prestressed concrete column with general end boundary condition.
The multivariable nonliner equation formulated in this study are solved by using the Bisection Method and to evaluate the critical load of the column. a Second Order Stiffness Analysis is perfonmed.
The solution scheme is suitable for computer application. The end restrainsts add on appreciable amount to the column ultimate capacity as to unrestrained columns.
For columns with L/H ≤ 30 due to the effect of end restraints, the ultimate capacity is same that of a short column.For the case of concentrically prestress columns, the column capacity decreases with the increase in the prestress ratio.
Depending mainly on the slenderness ratio, the prestressing steel ratio, and the stiffness of the springs, a concentrically loaded column may have a buckling failure( L/H ≤ 30), or a material failure(L/H ≤30)