The original Key Bridge collapsed after being struck by a drifting tanker. The replacement Key Bridge will feature five cable-supported main spans (as shown below), with a maximum span length of 1,665 ft. As part of the new bridge design, a comprehensive Structural Health Monitoring (SHM) system will be implemented for the main spans. CHI is leading the SHM design effort and is also responsible for developing the maintenance and inspection access provisions for the two new pylons.

​

The SHM scope covers key structural and environmental components, including stay cables, main girders, pylons, expansion joints, and wind conditions. The system will deploy a diverse sensor suite such as PTZ cameras, vibrating-wire strain gauges, GPS sensors, accelerometers, string potentiometers, acoustic monitoring sensors, humidity sensors, and tiltmeters. Detailed requirements have been established for data acquisition and operations, management, processing, storage, visualization, and cybersecurity to support reliable long-term monitoring and decision-making.

​

Scope of Work:

• Design of Structure Health Monitoring Systems for the Main Spans

• Design of Pylon Inspection and Maintenance Access