Case Study Report – Monadnock Construction

Name: Jason Siegfried
Date: 12/20/19

Describe the problem the customer needed solved:
They are placing a crane for 4 months and our job was to inspect a 96” x 120” rectangular sanitary line in NYC pre and post crane placement.

Explain the setting (site location, site type etc.):
The manhole access point was in the middle of the road and on the side of a construction site. The pipe had high and fast moving water running through it. The water was too high and too fast to be able to operate the standard robotic crawler fearing it would be washed down the pipe and lost. There was also a considerable amount of steam because the inside of the pipe was warmer than the outside air.

What technology, equipment or methods were used in solving the problem. (What was the solution to the problem?):
We solved the issue of fast moving water by building a floating VPI camera. We took the body of a robotic crawler with the rotating camera head and attached it to a hull.

The pipe also had a considerable amount of steam coming out of it, so once we lowered the VPI boat into the pipe, the camera fogged up. We decided to open another manhole downpipe to hopefully draw some of the steam out.

After the camera defogged, we were able to float the VPI boat down the designated section of pipe that needed to be inspected. Using a rope attached to the hull and the cord attached to the camera, we were able to pull the camera and hull back to the original launch point. We were then able to retrieve the VPI boat by pulling it back up the first manhole access point.

How did the customer benefit from the solution?
Preconstruction inspections can identify any issues as being pre-existing and therefore not caused by the construction work about to take place. In this case they are placing a crane for 4 months and the sanitary line is nearby. The DEP made them inspect the pipe before they place the crane to document the conditions of the line. We will go back to this job in early April to re-inspect the line to see if any damage has occurred from the crane placement. The customer will be responsible for any damages that occurred from the crane placement.

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