Title

Preliminary Evaluation of Siesmic Hazards for Emergency Rescue Route, U.S. 60, Missouri

Abstract

The Missouri Department of Transportation (MoDOT) has designated segments of a number of highways as emergency vehicle priority access routes in the event of an earthquake, including a section of U.S. Highway 60 in southeast Missouri. The designated transportation corridors must be reopened quickly following an earthquake, so MoDOT initiated a study to evaluate potential seismically induced damage to critical roadways and bridges. This study included evaluation of earthquake-induced landslide potential at two bridge sites, assessment of liquefaction susceptibility, and risk of possible flooding caused by earthquake-induced levee or dam failure along the 45-mile section of U.S. 60 between Poplar Bluff and Sikeston. This study is unique in that the expected degree of roadway damage is not as important a consideration as the ability of emergency vehicles to navigate the road following an earthquake. This is the first comprehensive study of emergency vehicle priority access routes in the midwestern United States. A simple ranking system was developed to assess the susceptibility of critical bridges and roadways to earthquake damage that could deny roadway use. With respect to bridge sites, the St. Francis River and Wahite Ditch bridges were among the most susceptible to traffic-disruptive damage. Based on a detailed investigation, slopes at the Wahite Ditch show marginal stability (1 ≤ FS ≤ 1.1), whereas those at the St. Francis River show instability (FS < 1) when subjected to 2 percent probability of exceedance (PE) earthquake loads. Liquefaction and flooding potential were estimated for U.S. 60 from Poplar Bluff to Sikeston, MO. Approximately half of this section, from Poplar Bluff to Dexter, is moderately susceptible to liquefaction, as defined by the number of 5-ft soil layers expected to exceed their critical cyclic stress ratios under 10 percent PE earthquake shaking. The entire roadway is moderately to strongly susceptible to liquefaction under 5 percent PE earthquake shaking. Similar results to 5 percent PE shaking are found for 2 percent PE shaking, with the exception of the section of roadway within 5 miles of Sikeston, which is characterized by severe liquefaction potential. Several stretches of U.S. 60 could be flooded and rendered impassable in the event of catastrophic failure of regional waterway levees or failure of the Wappapello Dam.

Department(s)

Geosciences and Geological and Petroleum Engineering

Keywords and Phrases

Earthquake; Flooding; Landslide; Liquefaction; Seismicity; Earthquake Damage; Seismic Hazard; United States; Populus Berolinensis

Geographic Coverage

Missouri

International Standard Serial Number (ISSN)

10787275

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2002 Geological Society of America, All rights reserved.

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