The objective of this paper is to describe the needs and tentative schemes for seismic instrumentation of the Cape Girardeau (MO) Cable-Stayed Bridge now under construction in the New Madrid area, the location of the 1811–1812 New Madrid earthquakes. The area is seismically active requiring hazard mitigation programs including those related to investigation of strong shaking of structures and the potential for ground failures in the vicinity of structures.

The acquisition of structural response data during earthquakes is essential to confirm and develop methodologies for analysis, design, repair and retrofitting of earthquake resistant structural systems. Particularly for urban environments, such data from structures including lifelines such as bridges, is one of the basic requirements for a thorough investigation of the effects of earthquakes on structures. Thus, in addition to structural arrays which should include sensors for soil-structure interaction effects, ideally, a seismic instrumentation scheme should provide recording ground motions at the free-field in the vicinity of the structures.

The instrumentation for the Cape Girardeau bridge will be deployed on (the superstructure and pier foundations) and in the vicinity of the bridge (e.g. free-field both surface and downhole and horizontal spatial arrays to assess the differential motions at the piers of the long span structure). The instrumentation scheme of the bridge will facilitate recording of the seismic response of this important lifeline during mid-size or large events. Furthermore, by lowering and adjusting the sensitivities of the recording systems, it will be possible to record ambient response of the subject bridge. The response data will be used by researchers and engineers to (1) assess the performance of the bridge, (2) check design parameters including dynamic characteristics with actual response, and (3) better design future similar bridges.

Furthermore, if properly configured, the instrumentation can be used as a health monitoring tool (a) to serve as an early warning system and/or (b) to assess if there is damage to the structure. This paper will detail options for an optimal instrumentation scheme for the subject bridge.

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