Damage Assessment of Monumental Structures in the 2011 Virginia Earthquake – Looking Back

(Article originally published on Oct. 8, 2012.  Revised and Updated on July 22, 2017)

On August 23, 2011, the Mid-Atlantic region experienced its strongest earthquake since 1897. The epicenter of the earth-quake was located near Mineral, VA which is approximately 80 miles southwest of Washington, D.C. and 45 miles northwest of Richmond, VA. Although the ground shook for only about 30 seconds, structural engineers in the region were very busy for several days after the 5.8 magnitude quake performing immediate damage and safety checks.  Upgrades and repair work continued for several years after the event.

On the day of the quake, the population of the eastern U.S. and southeastern Canada were surprised to experience a fairly large east coast earthquake with a magnitude of 5.8.  According to the USGS,  several small earthquakes occur every month in the eastern U.S., but this earthquake was among the largest to occur in this region in the last century.

USGS estimates that approximately one third of the U.S. population could have felt this earthquake, more than any other earthquake in U.S. history. Around 148,000 people reported their ground-shaking experiences caused by the earthquake on the USGS “Did You Feel It?” website. Shaking reports came from southeastern Canada to Florida and westward to locations near the Mississippi River.   Classified as a rare event  for the east coast, USGS also indicated that the earthquake was not a surprise in that it occurred within the Central Virginia seismic zone. This zone has been identified on USGS seismic hazard maps for decades as an area of elevated earthquake risk.  However, it is the largest known earthquake to have occurred in that zone.

Immediately after the earthquake, a number of Penn State AE alumni experienced and/or were involved in inspections, assessemnts and repairs of buidlings and other strutures that experienced damage of vaiours degrees.  One group of AEs in a construction site in downtown DC were on a conference call with a colleague in Boston when they exclaimed there was an earthquake.  The person on the phone in Boston thought they were making it up only to yell 12 seconds later something to the effect of : “It’s here!” (That exchange was courtesy of the east coast geology).   A feature story on Penn State AE alumni involvement with the earthquake can be found in the Spring 2012 AE Newsletter.

One of the Architectural Engineering Building Failures Visiting Practitioner Seminar features scheduled for September 2017 is a visiting lecture by Eric Sohn, P.E., a 2001 Penn State AE alum (formerly of WJE ) currently working as a structural engineer with the Penn State Facilities Engineering Institute.      Mr. Sohn and others from Wiss Janney Elstner (WJE) had the task of assessing damage to a number of monumental structures in the Washington DC area including the Washington Monument and the National Cathedral.  In particular, Mr. Sohn will discuss the role of the WJE Difficult Access Team (DAT) in gaining access to these types of facilities for close up inspection to obtain information for recommendations and repairs.

Currently, The Washington Monument is closed until spring 2019 while the National Park Service is modernizing the elevator to increase long-term reliability and safety.

There are a number of suggested readings and links available to learn more about the earthquake and the recommendations made by WJE on the project.  They include:

The Washington Monument Earthquake Update Page which includes the reports noted below in addition to links to photos, videos and the Incident reports from the National Park Service (NPS).

Summary of Initial Findings for the Washington Monument (WJE) Washington Monument Post Earthquake Assessment (WJE Full Report) Washington Monument Seismic Study

 

The National Cathedral was also heavily damaged in this earthquake.  An excellent source documenting the damage and repair process can be found on the earthquake repairs Cathedral website.

It is interesting to note that an eastern earthquake of similar magnitude occurred in Oklahoma in 2016.  Wikipedia notes:  The 2016 Oklahoma earthquake occurred on September 3, 2016 near Pawnee, Oklahoma. Measuring 5.8 on the moment magnitude scale, it is the strongest in state history. It is tied with the 2011 Virginia earthquake as the strongest in the central and eastern United States in the preceding 70 years.  This particular Oklahoma earthquake was a part of the 2009 – 2017 Oklahoma Swarm which has been attributed to the disposal of oil drilling wastewater back into the earth.

In order to fully appreciate and carry out follow up discussions on the presentation, you may need to know more about the basics of the earthquake and the corresponding performance of buildings and related structures.  Suggested readings on the topic of building earthquake performance such as the quakes in New Zealand that occurred around the same time as the one that struck the DC area and the followup one year later discussion of the Mineral Virginia earthquake in particular are provided below:

USGS One Year Anniversary – VA 5.8 Quake     2010 Canterbury, New Zealand Earthquake Summary     2011 Christchurch, New Zealand Earthquake Summary

 

Tags: , , , , , , ,

One Response to “Damage Assessment of Monumental Structures in the 2011 Virginia Earthquake – Looking Back”

  1. mkev
    July 23, 2017 at 12:21 am #

    Thought I would start with an item of engineering trivia. Did you know that the earliest seismic design provisions in the US were introduced in the Appendix of the 1927 Uniform Building Code (UBC) which was the first edition of the UBC. Few if any structures of the era of the washington monument were designed specifically for earthquakes, particularly on the east coast.

Leave a Reply