混凝土截面的轴力弯矩曲率全曲线解析法

On the assumption of plane section, idea elastoplastic model of steel and concrete constitutive relations of chinese Code for Design of Concrete Structures, strain area on section was constructed with Code's limits as boundary, inside which strain changed arbitrary, and three areas were divided according to changes of internal forces. By using the two edge strains as the independent variables and for two cases of the neutral axis in the section and outside, the analytical expressions were established including zone height, uniformity, position and arm coefficient of compression. Then the analytical expressions of moment and axial force were deduced at the state of arbitrary strains for the three areas. n-m-φcurvse with fixed compression,φ-n-m curvse with fixed curvature and with linear curvature change were set up by inverse method at the range from ultimate tension to ultimate compression. Through these curvses, it is clear for the values of yielding and ultimate limit state, changing regulations of course values, and the relationship and whole change process between moment, curvature and axial force on RC section.