Demolition of Putnam Street Bridge

By Carol Wright

(Originally published in Demolition Magazine)

It stood proud for 86 years in Marietta, Ohio, but took only a split second to tumble into the Muskingum River at 9:30 a.m. on April 27, 2000.

Using 400 Accurate Arms copper clad linear shape charges with RDX explosive cores, amounting to only 60 lbs. of explosives, the old Putnam Street Bridge was blasted in 28 milliseconds.

The project was planned, supervised and engineered by NADC-member Eastern States Wrecking Co. (ESWC) of Bristol, Pennsylvania with the assistance of W.J. Castle Engineering, PC, PE, of Lumberton New Jersey.

ESWC first removed the sidewalk planks, railing and their supports. The concrete deck was then broken apart and removed. Because of the 3-ton weight restrictions on the bridge, ESWC utilized lightweight Keibler Thompson Corp. remote controlled demolition equipment to perform the break out. The ESWC crew then installed rigging cables with buoys to various sections of the bridge, prior to the explosive demolition, so that retrieval of steel members from the river could be accomplished without divers

ESWC contracted the actual explosive demolition to one of the country's premier structural blasting firms, NADC-member Demtech Inc. of Dubois, Wyoming. Together, ESWC and Demtech formulated a blast plan to meet the stringent requirements of local, state and federal officials. NADC-member Protec Documentation Services of Rancocas, New Jersey was then contracted to perform pre-blast structure inspection and vibration monitoring. Protec spent three days inspection approximately 80 structures situated near each bridge abutment and later reported that all blast vibration levels fell within acceptable limits and adjacent properties suffered no effects.

Barges were stationed in the Muskingum River to handle and transport the steel. Using 80 ton Manitowoc 222 barge mounted crane, the steel was lifted out of the river and moved to the riverbank where it was processed for recycling.

Working under the direction of the U.S. Coast Guard, the navigating channel of the river was cleared within 24 hours of the detonation.

The bridge was demolished to make way for the new 11.4 million Putnam Street Bridge, which is currently being built by Kokosing Construction Co. The west end of the new bridge was only 4 feet away from the bridge being demolished and suffered no adverse effects from the blast.

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