Infographic: Shoring up iconic Washington Monument

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  • 7/27/2019 Infographic: Shoring up iconic Washington Monument

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    The 555-ft. (169 m) tall monument was renovated from 1998 through 2001. Architect Michael Graves designed the scaffolding.After being damaged during the earthquake of Aug. 23, 2011, it is being repaired again, inside identical scaffolding. The monumentis due to reopen in 2014. Billionaire David Rubenstein matched a $7.5 million allocation by Congress to pay for the work.

    The crack shown aboveis typical of manyfractures of panels in thepyramidion, the topmostpart of the monument The scaffolding does not

    contact the stones in thepyramidion section of themonument

    There are four motorizedworking decks on eachmonument face, with 3 ft.(1 m) of working spaceinside the scaffolding

    Scaffolding legs areembedded in concretefoundation pads, setaround monuments plaza,which distribute weight

    1 2

    3 4

    5 6

    7 8

    Source: National Park Service, The Washington Post, U.S. Geological Survey, Wiss, Janney, Elstner Associates, Inc., John Milner Associates Inc., MCT Photo Service Graphic: Robert Dorrell, Olivier Douliery 2013 MCT

    Shoring up iconic Washington Monument

    Cracks in panels near top

    Crack

    Crack

    Working up and downan enormous scaffold

    Most of the overall damagewas done in the pyramidion,but all four sides suffered

    1. Cracks instone, called aspall, near thepyramidioncapstone on thewest side

    2. Daylight

    shows throughvertical joint justabove the 450ft. (137 m) level

    3. Complexspall at site ofearlier repair,northeastcorner

    4. New crack,in stone andsealant, on anolder repair job

    5. Crack, westside, near top

    6. Fracture in tiebeam in theinterior, nearsouth side

    7. Daylightthrough anothervertical crack

    8. Scaffoldingreaching towardthe top

    Damaged stone panelson all sides of monument

    Examples ofearthquakedamage

    Workers on scaffold at monuments pyramidion

    On July 8, the scaffolds lights shine out

    Damage was heavier at outer corners of themonument; four methods will be used to make repairs

    Anchoring Stone piecessecured with adhesive;anchors drilled intointerior stone

    PatchingSpace is cutout aroundspot of amissingpiece ofstone; amatchingpiece is fit

    into space,attached withsteel rodsand adhesive

    SealingAdhesiveinjected intocracks;limestonedust addedto surface tohide thecrack

    Repointing Damaged mortar removed, replaced

    Bedrock an average depthof 80 ft. (18.3 m) belowbottom of foundation

    Types of repairs being done to side panels

    Granite

    Granite

    Stone

    Stone

    Scaffolding set upontemporary concrete pads

    Loam, fill, clay

    Loam, fill, clay

    Sand, clay mix

    Sand, clay mix

    Sand, gravel, clay

    Sand, gravel, clay

    Blue clay

    Blue clay

    Foundationconcrete, gneiss rubble

    Foundationconcrete, gneiss rubble

    Anchor brackets willconnect shifted externalmarble panels to interiormarble rib supports,adding stability

    Installing anchors

    Braces at cornersand center ofmonument sides,joined by steel cables,secure scaffolding

    Brace pads aremade of wood, coatedwith plastic foam toprevent scratchingstone slabs

    Scaffolding anchored

    by corner braces

    100

    200

    300

    400

    500

    Northface

    Westface

    Southface

    Eastface

    Damaged panels

    555 ft.(169 m)

    Anchorbrackets

    Anchorbrackets

    Internalstoneribs

    InternalstoneribsExternal slab

    External slab

    Scaffolding

    Scaffolding

    Crushed stone

    Crushed stone

    Concrete pad

    Concrete pad

    Scaffolding

    Scaffolding

    Work deck

    Work deck

    Tensioner

    Tensioner

    Cornerbrace

    Cornerbrace

    Pad

    Pad

    Scaffolding

    Scaffolding

    Cable

    Cable

    Platform

    Platform

    Motor

    Motor

    Scaffolding

    Scaffolding

    Pyramidion

    Pyramidion