Street Excavation

Early in my career as an environmental engineer, I sometimes did field work that involved soil and groundwater sampling. The type of soil sampling I did used shallow coring down to about 15 or 20 to obtain different depth soils to analyze for contamination. Number one rule before coring or digging for any reason, is to have all the utility marked. Most, if not all, states have a single number you can call and request the utility companies come out and mark where their underground pipes, wires, or whatever are. They would come and spray paint lines to denote their utilities, and then the drillers and I would know to avoid those areas. The sites I worked out were fairly simple, and avoiding utilities was pretty straightforward. Then there are old, densely populated cities like New York. I have never done any type of digging in New York City, and I hope I never do. The underground is a maze of pipes and wires and then below that are subways and basements and who knows what else.

I went to New York City this past Saturday. While walking around, I passed an area where the street had been excavated for utility work of some type. There were four guys cutting holes in a large diameter metal pipe. I asked one of them what the pipe carried, and he said it was for gas, but it had not been used in a long time. Because I am an engineering nerd, I of course had to take a bunch of photos, and what I saw confirmed my desire to never do any digging work there. My hat is off to the people who do. They must have to do the digging by hand, possibly with a tablespoon to get around all the pipes. The shoring looked like some crazy Tetris scene trying to put the beams around the pipes. The guys cutting the pipes had barely any room to work and that is not mentioning how they were bending down to cut.

So if you were ever curious just what types of utilities are below the streets of Manhattan, see below.

Rather large excavation area with many workers

Rather large excavation area with many workers. There were four cutting the pipe, one flagging traffic, and eight standing around, evidently waiting for the next phase or supervising.

Vertical shoring on the cut sides; the pipe the worker was cutting a hole is in foreground

Vertical shoring on the cut sides; the pipe the worker was cutting a hole is in foreground

Worker cutting the large previously decommissioned gas pipe

Worker cutting the large previously decommissioned gas pipe

Worker cutting another part of the pipe in a very cramped area

Worker cutting another part of the pipe in a very cramped area

A couple of previously cut pipes in the ground profile

A couple of previously cut pipes in the ground profile

Pipes crossing everywhere

Pipes crossing everywhere

Multiple levels of horizontal shoring

Multiple levels of horizontal shoring

A conduit containing wiring

A conduit containing wiring

Driving Pilings

There is a bridge that is being demolished near my office that is now my destination and entertainment on my daily lunchtime walks. I previously posted video of the demolition of a concrete column. The other day during my visit, a crane with a hanging vibratory hammer was driving steel sheet pilings into the riverbed to form a cofferdam. There was already a cofferdam around one of the bridge piers, which has now been demolished. I am assuming this new cofferdam will surround the next pier, so it can be removed. The before and after photos of the pilings being driven are below as well as video of it happening.

Driving pilings, before

Driving pilings, before

Driving pilings, after

Driving pilings, after

Excavator Destroys a Concrete Column

Excavator with concrete crusher twirling rebar

Excavator with concrete crusher twirling rebar

There is a bridge over Four Mile Run that connects Alexandria and Arlington, Virginia that is being destroyed. I love walking over near the site and watching the destruction take place. Today I took some video of (what I am fairly sure is) an excavator with a concrete crusher pound and crush the concrete of a former column. It then separated the rebar and twirled it like ribbon to consolidate it. So very cool to watch.