CONSIDER THE SLAB AS SIMPLY SUPPORTED ON BEAMS AND CALCULATE THE MOMENT THEN CALCULATE THE REQUIRED THICKNESS OF GLASS BY COMPARING THE MOMENT WITH THE TENSILE STRENGTH OF GLASS (TENSILE STRENGTH OF GLASS WILL BE PROVIDED BY THE MANUFACTURER)
this is because of high stiffness of internal columns which are attracting more moments which produces more elastic shear thats why middle columns have high shear value than the end columns.