Tuesday, January 3, 2012

Washington Monument Earthquake Assessment Report

Over Christmas, the National Mall quietly released the Washington Monument Earthquake Assessment (opens .pdf file).  It's not exactly a page-turner; it's a scientific report.  But if you read it, you will find some neat pictures of missing hunks of rock.  As I walk by every day, I look up at the building and notice the blemishes even with the naked eye.  It's not quite what you see in the post-apocalyptic game Fallout 3, a Washington Monument that looks like Swiss cheese.

For the "too long; didn't read" crowd, here are some highlights with my emphasis in bold:

  • Six marble panels that form the exterior surfaces of the pyramidion developed earthquake-related cracks that extend through the full thickness of the panel. These through thickness cracks also extend over the full height of the panel and vary from approximately 1/4 inch to 1 inch in thickness. Three additional panels developed cracks that do not appear to have migrated through the full thickness of the panel.
  • The portions of the marble rib units that serve as bearing surfaces for the support of the exterior marble panels experienced cracking. Cracking of the rib bearing surfaces occurred on some of the ribs on each of the four sides of the pyramidion.
  • A large spall was generated directly below the cruciform shaped keystone of the pyramidion in the ‘H’ rib course of the pyramidion.
  • The southwest cornerstone unit at the ‘G’ course experienced a permanent lateral offset to the south of approximately 1 inch, and to the west of 1/2 inch, relative to the stone unit of the rib in the course below.
  • Mortar on the interior and exterior face of the masonry is missing at numerous vertical joints from the 450-foot level to the 500-foot level of the monument. Daylight is visible at a number of the vertical joints where mortar is missing.
  • Spalling of the exterior stone was observed over the entire height of the shaft of the monument with spalls being larger and more clustered above the 450-foot level. Some spalls at this level were the full thickness of the masonry block.
  • Lateral movement and offsets on the exterior were observed above the 450-foot level, and were pronounced at the southwest corner of the monument.

Recommendations for repairs include replacing spalls and supporting them with stainless steel braces.  The recently-passed Omnibus bill includes an allocation of $7.5 million to repair the Washington Monument, to be "matched on a 1:1 basis by a private citizen."

The Washington Monument remains closed to the public until the building can be repaired.  There is no timeline.

Here are some pictures I took with my phone.  Not what you're used to if you read this blog, but I can't exactly lug my camera around while I'm at work.  I'm too busy working.

 "It's leaning!"  No, it's not.  It's just crooked camera work.  That is, however, the President going to a meeting.

I took this photo from near 14th and Independence Ave. SW one morning.  There are buckets dangling at the top of the monument because they were doing inspection/repair work that week.

And here's a picture of the monument at sunset after a day of rain.  There was a nice rainbow I couldn't get into the shot.  When it rains, water gushes through cracks in the monument, though they've tried to seal all the cracks to help the old girl get through the winter.

2 comments:

Marianne, aka Ranger Anna said...

Yowza! I'm glad with were able to get the boys up there and have the pictures on discs. Do you mean that someone is going to pony up nearly 4 million bucks? I could so hug her/him!

Nathan King said...

Congress pays $7.5M, someone else comes up with another $7.5M.

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