16 th World Conference on Earthquake Engineering, 16WCEE 2017 Santiago Chile, January 9th to 13th 2017 Paper N° 2220 Registration Code: S-V1463182651 PUNCHING SHEAR IN WAFFLE SLABS, ANALYSIS OF EXPERIMENTAL BEHAVIOR E. Arellano-Mendez (1) , O. M. González Cuevas (2) (1) Professor, Department of Materials, Universidad Autonoma Metropolitana, México, eam@azc.uam.mx (2) Professor, Department of Materials, Universidad Autonoma Metropolitana, México, omgc@azc.uam.mx … Abstract Eleven full-sized posttensioned waffle slab-column connections subjected to axial load and flexural moment were tested to study their mode of failure, strength and ductility. The test variables are: 1) provision of stirrups or stud shear reinforcement; 2) spacing between stirrups or shear studs; 3) slab thickness; 4) size of the solid region around the column; and 5) relationship between the applied axial load, Vu, and the punching shear strength of the slab with axial load and without shear reinforcement, VcR. Most tests carried out in this type of connections, according to a bibliographical review, used solid flat slab. In this research, waffle slabs were used, being more used in Mexico than solid slabs because economic reasons. The ductility of the connections was of special interest, since this type of structures are usually considered of low or medium ductility because the punching shear failures are brittle. It has been found that the maximum IDR (interstory drift ratio) reached in structures with flat slabs-columns connections depends on the relation between Vu and VcR, so this was one of the main variables in the research. Keywords: shear; punching; slabs; waffle; experimental