Abstract：Quasi-static tests were carried out on fifteen frame beam-end specimens with longitudinal HRB500 reinforcements and 970MPa-PC-steel-bar stirrups. The shear ratios of specimens were 1.4, 2.5 and 3.4, respectively. Seismic behaviors, including failure pattern, hysteresis loops, skeleton curves, displacement ductility, stiffness degradation and ultimate bearing capacity of concrete frame beam-end with high-yield strength stirrups and high-yield strength longitudinal reinforcements, were studied. The influence of mean confinement stress ( ) was analyzed. Then the test results were used to analyze the diagonal bearing capacity calculation formulations in relative standards of China, Japan and America. The results show that the increasing mean confinement stress could limit the crack width, reduce the damage degree, make the hysteresis loops plump, and improve the seismic behaviors and ultimate bearing capacity of specimens. However, the increase of ultimate bearing capacity and displacement ductility of bending failure specimens is tiny. Unreasonable mean confinement stress would lead to joint surface failure. The longitudinal reinforcements of all specimens and PC steel bar stirrups in the diagonal tension failure specimens yielded at the peak load. But PC steel bar stirrups in the shear compression failure and diagonal compression failure specimens did not yield，whose maximum stirrup strains were between and . When was taken as the measured yield strength and was less than 3.5MPa, the average ratios of calculation value calculated by Code GB 50010—2010 and specification CECS 356—2013 to the experimental value were 0.91 and 0.87 respectively.
