Reinforced Concrete Frame Columns In Yield (cross-jin) Shear Capacity In The Pilot Study And Mechanism Analysis

Postgraduate: Guan PinwuUnder the Tuition and Supervision of Prof. Zou Yinsheng and Prof. Liu LlxinThe deformation limits of columns designed following current codes of many countries dominated by concrete crushing or longitudinal reinforcement buckling within yield hinge regions near columns ends, rather than shear failure. But the seismic investigation shows the unavoidable shear failure of columns. On the other hand, the ductility of structures is vital to æ…¶apacity design* philosophy in seismic design. For a seismic shear capacity predictive equation for ductility reinforced concrete columns the shear tests of 10 columns and analysis under cyclic load have been made.1.The simulation of Japanese building-research-installation (SBRI), a simple and reliable experimental installation, is created to meet with the demand of tests.2.The suffering failure of columns within yield hinge regions and classified standard are expressed in detail to end the confusion of expression and application in the subject area in China.3.The action of main affected factors, such as axial force, shear-span ratio, transverse reinforcement amount and so on, are described in detail to study the shear behavior and mechanism of columns under cyclic load.4.The shear contribution of concrete and transverse reinforcement as to the increasing of columns* displacement ductility level is also investigated. With the developing of tests the shear contribution of concrete is decreasing, while the shear contribution of transverse reinforcement is increasing till transverse reinforcement yielded.5.The truss-arch model is brought up to analyze the shear capacity of columns within yield hinge regions. The shear contribution of concrete and transverse reinforcement, the response of various displacement ductility factors under cyclic load is described. A seismic shear capacity equation for ductility and non-ductility columns is proposed to amount for the reduced shear contribution of concrete as to the increasing of displacement ductility levels.6.The behavior of columns* transverse displacement within yield hinge regions is also discussed based on truss-arch model.7.The seismic shear capacity design equation of columns with various ductility levels is proposed in statistic method on the basis of test data collected from Japan and China to simplify the equation resulted from truss-arch model. The equation is also proposed to modify Chinese code (GBJIO-89).8.The reliability analysis of the seismic shear design equation is also expressed to show the reliability factor and security of the equation.9.Some detail requirements, such as the maximum axial load ratio in columns, the minimum of confined transverse reinforcement within yield hinge regions and so on, are also proposed to modify Chinese code (GBJ1O-89).The main achievements and proposals in this paper are accepted by new Chinese Reinforced Concrete Structure Design Code (GB500 I O-XX).