Editing Philadelphia City Hall (section)

== Masonry Construction ==

Philadelphia City Hall is the '''tallest masonry load-bearing building in the world'''. Unlike modern skyscrapers that use steel frames to support their weight, City Hall's massive stone walls bear the entire structural load of the building. No steel frame was used in its primary construction.<ref name="asce"/>

The building was constructed using brick faced with white marble and limestone. Because the walls must support all the weight from the floors above, the basement walls are up to 22 feet thick at the base. The foundation beneath the tower rests on a bed of concrete 100 feet square and 8 feet 6 inches thick. The basement story itself stands 18 feet 3 inches high, built from white granite blocks weighing 2 to 5 tons each.

The tower's upper portion does incorporate a wrought-iron framework designed by civil engineer C.R. Grimm, but this supports only the tower and statue—not the main building. The framework was engineered to handle the 27-ton bronze statue while withstanding wind loads of 50 pounds per square foot.

Note: The Mole Antonelliana in Turin, Italy was briefly taller, but after a 1953 storm collapsed its spire, Philadelphia City Hall assumed the record for tallest masonry building, which it has held ever since.