 This buttressing plan was adopted by the other major 13th-century cathedrals, notably Amiens Cathedral and Reims Cathedral.Another architectural innovation at Chartres was the design of the massive piers or pillars on the ground floor which receive the weight of the roof through the thin stone ribs of vaults above.The weight of the roof is carried by the thin stone ribs of the vaults outwards to the walls, where it is counterbalanced by the flying buttresses, and downwards, first through columns made ribs joined together, then by alternating round and octagonal solid cored piers, each of which bundles together four half-columns.