Research progress in bearing capacity calculation methods of column connections

Abstract:

For the further research on the bearing capacity of slab-column connections, the engineering accidents of slab-column structure collapse caused by the failure of slab-column connections at home and abroad were introduced, and the problems existing in the calculation methods of bearing capacity of slab-column connections were pointed out. The test results and prediction formulas of the failure surface inclination angle of punching or bending-punching failure of slab-column connections were analyzed. In view of the large deviation between the calculated results of the inclination angle of failure surface obtained according to the prediction formulas and the test values, a method was proposed to obtain the failure surface inclination angle by fitting the bearing capacity test results of slab-column connections in three-dimensional coordinate system, which takes the inclination angle of the punching and bending-punching failure surface as the ordinate and the longitudinal reinforcement configuration eigenvalue ρfy/fc as well as the punching span ratio λ=(M_i)/[(V_ih0i)] as the abscissa. Considering that the Chinese code GB 50010—2010 Code for Design of Concrete Structuresonly provided the punching bearing capacity formula, the existing calculation formulas of the bearing capacity of slab-column connections at home and abroad were reviewed, and the influences of the section height of the slab in each formula were analyzed. The analysis results show that the calculation of bearing capacity of slab-column connections should be treated differently according to punching failure, bending-punching failure, and direct punching failure, and the inclination angle of punching or bending-punching failure surface shall be reasonably considered in the calculation. The influence of key parameters such as punching span ratio and longitudinal reinforcement configuration eigenvalue should be comprehensively considered in the calculation of bearing capacity of slab-column connections, and the criterion and bearing capacity calculation method of direct punching failure of slab-column connections should be further improved.