Punching shear in edge and corner column slab connections of flat plate structures.
Creators: name: Sudarsana, I. Ketut.
Publisher: name: Université d'Ottawa / University of Ottawa
Year: 2001
Subjects: subject: Engineering, Civil.

description: The behavior and strength of edge and corner column slab connections of flat plate structures subjected to shear force only, moment only as well as combined shear force and moment were investigated. A two bay by two bay flat plate structure (nine columns) and eight isolated edge column slab connections were constructed and tested to failure. After the tests of the four edge column connections of the continuous slab were completed, the edge connections were repaired using two types of concretes (normal concrete and CAB expansive concrete) and tested to failure. Interaction diagrams between shear force and unbalanced moment at edge column slab connections based on building code provisions (ACI 318-99, CSA A23.3-94 and CEB-FIP MC90) and three alternative approaches (Regan's approach, the Truss Model and the Strip Model) proposed in the literature are examined using the results of the present experimental work. Interaction diagrams for corner connections calculated using Regan's approach and the building code provisions are compared with the experimental results. The shear strength of edge and corner connections is calculated according to ACI 318-99, CSA A23.3-85, BS8110-85, CEB-FIP MC90 and the alternative approaches of Regan, Sherif, Gardner, Elgabry, the Truss Model and the Strip Model. All alternative approach predictions of shear strength of edge connections, except Sheril's, are conservative. The average ratio of measured shear strength to calculated shear strength ranges from 0.90 to 1.30 with coefficients of variation (COV) ranging from 0.18 to 0.40. Gardner's approach, that considered a linear shear stress distribution as in ACI 318-99, with a critical shear section taken at the column perimeter or perimeter of loaded area gives the most conservative and the least scatter of the test results compared with the other proposed approaches. The measured shear strengths of the corner connections are compared to the calculated shear strengths based on the building code provisions and five alternative approaches available in the literature (i.e. Ingvarsson's, Regan's, Zaghlool's, Gardner's and Desayi's approach). On the basis of the present test results, the effects of load eccentricity (M/V) and reinforcement ratio (rho avg) on shear strength of edge column slab connections are investigated. The reduction in shear capacity of edge connections due to the increase in M/V ratios approximates a logarithmic function. The effect of the reinforcement ratio on the shear strength of the present tests on the edge and corner connections calculated using the North American codes is not obvious. However, tests by Zaghlool (1973) and Regan (1981) show that the shear strength increased with an increase in reinforcement ratio. The strength and stiffness of repaired edge connections were investigated using the four, previously failed, edge connections of the continuous slab specimen. Connections repaired using normal concrete can have similar strength and stiffness as the original connections. However, the connections repaired using the CAH expansive concrete exhibited less strength and stiffness compared to the original edge connections.