JW Fishers’ Sonar Critical to Historic Bridge Demolition, Recovery

Pieces of the historic Highway 47 Bridge scattered on river bottom.
The historic 1936 Highway 47 Bridge over the Missouri River was demolished this past spring. The old bridge was located 12 ft. from the new bridge that was built over the last several years. Being as close as it was, the demolition had to be precise, accurate and safe.
On April 11, 2019 the bridge was demolished via strategically placed explosives. The blast dropped the roughly 2,000-ft. span using 145 lb. of explosives, 750 individual charges and 8,000 ft. of detonation cord. Once the demolition was complete, the underwater recovery tasks began and modern technology was needed to locate the pieces for safe and efficient removal.

Three Rivers Diving Inc. was tasked with locating the pieces of the Highway 47 Bridge from the Missouri River waterway after demolition. The company used JW Fishers’ Side Scan Sonar System. The sonar was mounted on a fixed beam to the bow of the boat and used to locate the bridge section and help position a crane barge.
Three Rivers Diving used the sonar in another removal project. This time, a pier that was secured to a bridge had taken so much abuse that it fell into the water. Three Rivers Diving was asked to identify the remains and remove the debris from the water. The sonar was used to locate the position and prep the site.
For more information, email info@jwfishers.com or visit jwfishers.com.
A scene from the bridge demolition process.
Pier section on bottom of waterway.

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