The City of Chicago constantly faces the challenge of upgrading its aging infrastructure - sidewalks, roads and bridges as well as water and sewer lines that require either urgent repairs or routine replacement. One of those tasks is replacing vaulted sidewalks, created many years ago with a space underneath to transfer coal into store cellars. Once they deteriorate, the sidewalks need to be broken up and removed, after which crews fill the space with stone and pour a new concrete walkway.
Chicago city crews typically use Gradall excavators for vaulted sidewalk replacement work, including one north side retail district where they used a new XL 4100 IV model.
It's an extremely versatile machine, said Kevin Kelly, who has been operating mostly Gradalls for more than 10 years. Kelly mounts a hydraulic hammer attachment on the boom end to break up concrete, using the tilting boom to precisely place the hammer's tool, which is especially important working close to store walls. Next, he changes to a pavement removal bucket - again using precise boom control to carefully pull out pieces of sidewalk.
It takes me only two to five minutes to change attachments, said Kelly. "It's pretty simple if you've done it often enough."
The low-profile boom can be maneuvered under and around a number of obstructions on this job, avoiding contact with posts, signs and trees throughout the retail district. Because of tight working conditions, the excavator's shorter rear swing is able to minimize impact on normal traffic flow. The congestion also requires Kelly to pick up pieces of concrete and drive the carrier to a nearby dump truck using the upper cab repositioning feature.
I've driven older XL 4100 models before, and by comparison, this new one drives like a Cadillac, said Kelly. "I drive it out from the equipment yard to one or more jobs during the day and then back to the yard, and the difference is like night and day."
Many other days, Kelly says he operates the XL 4100 IV as part of the effort to create handicap ramps at every intersection in the city. "Tilting the boom, I can usually grab a corner of the old concrete at the edge of the sidewalk and pull it up," he said, adding that the boom versatility makes it possible to demolish concrete for about three ramps a day.
For more information about Gradall excavators call (800) 445-4752.