Vibration Monitoring for Historic Bridge

City Arch River bridge site

Geotechnology was selected by CityArchRiver 2015 Foundation to perform the precondition visual surveying and baseline vibration monitoring for upcoming St. Louis Arch grounds (Jefferson Memorial) construction work. The purpose of this project is to establish and implement a vibration monitoring program to assist in protecting various structures in the vicinity of planned CityArchRiver demolition and construction activities. Historic Eads Bridge is situated north of the project area. Constructed in 1874, the bridge carries both highway and rail traffic across the Mississippi River. The Eads Bridge is connected to a Metro tunnel structure consisting of two parallel arch sections generally with block walls and a brick arch roof. Both structures are considered historic and of concern for construction-related damage.

Geotechnology performed a precondition survey using photographs and video-recording at select street and bridge locations and determined the locations for crack gauges to be monitored during construction. This work was performed along operational Metro tunnel and bridge rail lines at night so as not to impact Metro’s operations and required specialized Metro Tier I and II training.

Construction vibration limit guidelines were developed based on location, background levels and structure condition. Locations for crack gauges to be monitored during construction were determined. Protocols for measuring and reporting construction vibrations, as well as stop-work and response plan requirements, were developed. During construction multiple vibration monitors will be set near the structures of interest. Vibration monitoring will be performed during demolition of the garage, rock removal and drilled pier installation, in addition to other intermittent construction activities. The vibration monitors will be remotely connected to a text alert system in the event that vibration levels approach or exceed the specified limits.

To learn about other services provided for the CityArchRiver project, please visit or contact your branch’s CMT Manager: Jeff Klein, P.E. 314-997-7440 in St. Louis, MO; Justin Donovan, 901-353-1981 in Memphis, TN; Luke Heuerman, 618-345-4811 in Fairview Heights, IL or Steve Damron, 913-438-1900 in Overland Park, KS.