History
From the Archives: August 5, 1920
Image from ENR Archives
This 1920 cover image depicts a four-man team doing high-speed block-laying as part of a channel improvement project on the Miami River in Dayton, Ohio.
They are building a flexible concrete mattress by stringing the precast blocks using steel cables. Two cables are inserted into each block, forming rows 20 ft wide. At each end excess lengths of cables, called “pig tails,” were left to be attached to anchor blocks to be installed later.
During each 10-hour shift the team installed 500 blocks, covering 1,000 sq ft, each block being 21 x 12 x 5 in. and weighing 118 lbs.
The blocks were lifted into position using long-handled tongs which permitted workers to grasp and carry each block without stooping.
The article attributed the crew’s fast pace to the men being “skilled old employees” as well as “the personal direction of the work by a contractor ingenious in devising methods and in maintaining close relations with his workmen.”
Subsequently a separate revetment crew would drive foundation piles, mold the slope slabs in place and pour the toe-walls, cutoff walls and anchor blocks.
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