Hoover Dam Monument Plaza

U.S. Bureau of Reclamation, Lower Colorado Regional Office
Boulder City, NV

Investigation and Conservation Assessment of Terrazzo Plaza

WJE was retained by the U. S. Department of the Interior, Bureau of Reclamation, Lower Colorado Region to document current conditions, determine the causes of deterioration, and provide recommendations for preservation of the Monument Plaza site, including the extensive unbonded, bonded, and precast terrazzo of the plaza and terrestrial compass as well as the brass features, figural sculptures, flagpole, and granite base.


Following the dedication of Hoover Dam in 1935, Monument Plaza was commissioned to celebrate the feat of engineering embodied by the dam and to commemorate those who lost their lives during its construction. Oskar Hansen, a Norwegian-born naturalized American citizen, was appointed consulting sculptor for the Monument Plaza in 1936 following a national competition. Work began immediately and was completed on December 17, 1937.


The plaza paving is composed of cementitious terrazzo with an elaborate inlaid celestial map that is meant to depict the exact position of prominent stars, constellations, and planets in the Northern Hemisphere at the date and time at which President Franklin Delano Roosevelt dedicated Hoover Dam. The plaza features two 30-foot-tall bronze Winged Figures of the Republic, a flagpole set on a diorite granite base, and a terrazzo-clad precast concrete terrestrial compass with twelve bronze plaques, each representing a sign of the zodiac.

WJE researched the history of construction and subsequent repair of Monument Plaza and its components; completed an on-site investigation of all elements of the plaza, including the removal of materials for laboratory analyses; and developed prioritized repair recommendations from minimal intervention to full scale restoration to provide options depending on the short-term and long-term resources available.