Repairing the Washington Monument
The newly restored Washington Monument reopened almost three years after the Aug. 23, 2011, earthquake caused enough cracks and breaks to force it to close. See the extent of the damage and how it was fixed:
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Stainless steel anchor bracket
Heaviest damage in top
Stone masonry on all four sides of the National Monument was damaged during the earthquake, but the top section, known as the pyramidion, was most affected.
Repairing the top
Spalling or breakage of exterior panel corners, cracking of vertical “rib” supports and shifting of vertical joints must be addressed. Installation of stainless steel
anchor brackets would
connect exterior marble
panels to interior
Damage to core
Masonry damage was prevalent along outer corners of the structure. Repairs will involve these four techniques:
Loose fragments were secured with adhesive and stainless steel anchors that were drilled in to the backing stone.
A rectangular shape was cut around missing stone and filled with one that matches the space and reinforced with stainless steel rods and mortar.
Cracks were injected with epoxy-based adhesive until completely filled. Limestone dust was sprinkled on the surface to mask the crack.
Damaged lime mortar was removed and replaced. The water-permeable material allows moisture to flow off of the structure instead of trapping it in the stones.
The base of the monument extends about 35 feet below ground level and sits on several layers of sand and clay.
Loam, fill and clay
Sand and clay
Sand, gravel and clay
SOURCE: National Park Service. GRAPHIC: Alberto Cuadra, Kathryn Faulkner, Cristina Rivero and Michael E. Ruane - The Washington Post. Published Aug. 23, 2012.
A team of engineers, masons and stone carvers soon will begin fixing damage from the August 2011 earthquake at the National Cathedral, a delicate process that is expected to cost at least $15 million and take a decade or more.