Seismic Application for Interface Load Pins
The range of applications of force measurement is wide-ranging across many industries. You can find Interface Mini Load Cells are frequently used to measure minute forces in precision medical devices, while our jumbo precision load cells that are rated for 2,000,000 pounds of force (lbf) are used to measure the force of rocket thrust.
Interface recently completed another extraordinary force measurement solution for a large scale infrastructure project, the first of its kind for the 51-year-old company. Engineering and solution experts created custom load pins to measure the seismic force on the Gerald Desmond Bridge. There are interesting details that give a perspective on how force is used to provide safe passages.
Sensors are essential in innovation, with a dependency on accuracy and reliability that impacts lives and ingenuity.
BACKGROUND
The Gerald Desmond Bridge, a bridge located in Long Beach, California, opened in 1968. It is a major commuting route for the region, and a major trade corridor carrying 15 percent of all containerized cargo imported to the United States. The bridge connects Terminal Island, the heart of the port complex, with the Long Beach Freeway as well as downtown Long Beach. In 2012, a large civil construction contractor was tasked with replacing the existing steel arch bridge with a new suspension bridge rising more than 200 feet over the water.
CHALLENGE
The contractors, an Interface customer, wanted to find a way to measure the force on the Gerald Desmond Bridge in the event of an earthquake. The goal was to continuously monitor the standard force created by regular traffic, as well as the seismic force before, during, and after earthquakes. The monitoring sensors needed to be integrated into a dampener that would be attached to the structural tower. The solution that would allow the company to monitor force from emitted data to cross-reference the standard traffic force with the seismic force to understand its effect on the bridge. Its purpose is to help with predictive maintenance and influence future bridge designs to better compensate for the forces of an earthquake or other natural disasters, which are common in this part of the world.
SOLUTION
Interface was engaged to create a unique infrastructure solution. It required a custom product that could handle the inimitable and considerable force of a bridge under every scenario of distress. Interface engineers developed a custom load pin to handle the force of movement in the bridge in the event of an earthquake. The load pin is much larger than our standard version and is rated at 900,000 lbf. The large load pins are designed to be integrated into the dampener with data acquisition modules connected to the load pins.
RESULTS
With the integration of Interface’s custom load pins and data acquisition module collect data at all times. The sturdy construction of our load pins and 900,000 lbf rating allow for readings during all degrees of seismic activity. We are also able to ensure product durability because the failure rating of the custom load pins is maxed out to 2.7 million lbf. An added benefit of this project was the Interface R&D efforts applied to create future data acquisition modules like this that utilize wireless technology.
Source: Ted Larson, VP of Product Development
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