| A series of full size prestressed concrete specimens, representing the connection of a concrete slab with an edge column were tested. The amounts of the prestressed and the non-prestressed reinforcements were varied while the flexural strengths were unchanged. The columns were subjected to an axial load of constant magnitude and the column was subjected to unbalanced moment reversals of increasing amplitude up to failure, representing the effect of earthquake. The specimens were provided with stud shear reinforcement (SSR). The arrangement and the spacing of the stud shear reinforcement remained constant in all slabs.; The objective of this research was to compare the ductility of prestressed slabs with the ductility observed in an earlier series on non-prestressed slabs. In addition the results will help develop design recommendations of connections that can withstand, without punching, the motion anticipated in a severe earthquake.; This thesis reviews the punching shear seismic design procedures for flat slabs, with and without shear reinforcement, developed by Megally and Ghali (2000a), later adopted by ACI 421.XR-04. Because all specimens contained shear reinforcement, this thesis comments only on the design procedure for prestressed flat slabs containing shear reinforcement.; It is concluded that the design procedures reviewed, intended for non-prestressed slabs apply also to prestressed slabs having an average prestress of 0.4 to 1.1 MPa. In addition, the ACI 318-02 provisions for design of prestressed and non-prestressed edge slab-column connections for punching shear with SSR are conservative and should follow the punching shear strength design procedures recommendations by ACI 421.1R-99, ACI 421.XR-04 or CSA A23.3-94. Furthermore, for seismic design, the upper shear strength limits suggested by ACI 318-02 and ACI 421.1R-99, (1/2) f'c and (2/3) f'c , respectively, can be increased, for seismic design, to (5/6) f'c , as recommended by ACI 421.XR-04. |
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