Behavior and Damage of the Washington Monument During the 2011 Mineral, Virginia, Earthquake

This paper investigates the potential causes of the damage to the Washington Monument sustained from the 2011 Mineral, Virginia (USA), earthquake through time-history dynamic analysis. Ambient vibration fi eld test data were obtained and utilized to calibrate a fi nite element model of the structure and its foundation. The impact of the foundation modeling and the uncertainties associated with the material properties of the stone and iron, in the absence of in situ material testing, were investigated through several parametric studies, in which the material property values are permuted at three (upper, average, and lower) levels to bound the predicted dynamic characteristics of the structure. Because ground-motion data recorded in the Washington, D.C., area during the earthquake are scarce, the ground motion at the Washington Monument site was simulated using an angular transformation of the recorded ground motions in Reston, Virginia, deconvoluted to the bedrock level and upward propagation of the rotated motions to the ground surface based on soil profi les in Reston and the Washington Monument site provided by the U.S. Geological Survey. The fi nite element model of the Washington Monument shaft subjected to these bidirectional earthquake records showed high acceleration amplifi cation at the observation level, as well as tensile stress concentration at the ~107 m level. These observations correlate with the damage observed in the pyramidion section and upper levels of the Washington Monument shaft following the 2011 Virginia earthquake.