75 seismic sensors will be installed in California bridge

Multiple sensors that will measure the forces imparted on the span during an earthquake will be installed in a replacement bridge under construction in California.

The bridge, located in Long Beach, the 2^nd busiest port in the U.S., will stretch 8,800 feet over the Port and will replace the Gerald Desmond Bridge in 1 year. Infrastructure has included earthquake sensors (accelerometers) since the 1970s. The innovation of the project is that the new bridge will have sensors incorporated into the design from Day One, according to Duane L. Kenagy, an engineer and the port’s interim deputy executive director. Strong Motion Instrumentation Program, an agency of Dr. John Parrish, head of the California Geological Survey, will be among those who will manipulate the sensors data. Those data will be also saved in the state’s database of earthquake knowledge.

The span is near two active faults (Newport-Inglewood and Palos Verdes) capable of delivering huge temblors such as the M_w 6,4 earthquake that leveled Long Beach in 1933. Moreover, the distance between the bridge and the infamous San Andreas Fault is only 50 miles.

The replacement, which will cost about $1.5 billion, is significant as the construction is the first cable-stayed vehicle bridge in California. In this type of bridges, the main span deck is entirely supported by cables that are connected to towers. It is a design capable to withstand powerful seismic forces. It is estimated that the new construction will last at least 100 years. Among its features, elastic “points of isolation” enable segments to move independently without damaging other sections whereas joints and bearings are designed to fail under high stress and to be replaced quickly after an intense earthquake.

Source: NYpost.com