When you're a contractor, time is always of the essence. But this is especially true when you're the demolition contractor on a multi-phase roadway project involving several alterations and updates to the Chicago Skyway — the vital artery connecting Chicago and northwest Indiana.

Over the past several years, Brandenburg Industrial Service Co., based in Chicago, has frequently performed work on this major roadway. The Chicago Skyway is a 7.8-mile elevated toll road built in 1958 to connect the Dan Ryan Expressway to the Indiana Tollway.

The demolition work being performed by Brandenburg includes the removal of concrete decking, parapet walls, structural steel, foundations, and asbestos. The project has placed both extreme time and physical constraints on the demolition firm. For example, the work typically has to be performed in quick intervals, allowing for construction crews to begin reconstruction immediately after demolition is complete.

In addition, Brandenburg has been forced to complete its portion of the work while contending with many obstructions, including adjacent structures and active roadways, railways and waterways.

The scope of the work requires Brandenburg to perform selective and total demolition of various sections of the roadway. The selective demolition entails that Brandenburg crews remove concrete parapet walls and bridge decking, while protecting remaining steel support structures. The company also performed total demolition of multiple ramps and support structures, including pier removal.

All of the work must be performed without disrupting traffic and adjacent railroad operations. Because of this, safety has been a top priority, and Brandenburg crews have provided protective barriers. The time constraints and safety issues make this demolition project so unique, says John O'Keefe, marketing manager for Brandenburg. Not only do crews have to work fast, but they also have to work safe.

Taking All Necessary Precautions

Recently, Brandenburg began demolition on portions of the main bridge, which required them to remove all of the bridge decking while keeping the steel support structures intact. For this type of work, the company enlists its fleet of Bobcat S300 skid-steer loaders.

Using hydraulic breaker attachments on the loaders, Brandenburg workers break down the parapet and diving walls bordering the roadway into concrete chunks. "We have to be extra cautious on these jobs because we're elevated, so you not only have to prevent material from entering the adjacent roadway, but you also have to prevent it from dropping below," O'Keefe says.

So Brandenburg crews take several safety precautions. First, decking is installed underneath the bridge before beginning demolition. Crews also use bridge boxes to catch material so that it doesn't fall into active areas below the bridge. Depending on the section of the Skyway bridge where work is being performed, crews can be working above vehicle and railway traffic, industries and a river.

Once the S300 loaders have chiseled out rectangular sections of the Skyway, the 3,000-pound rated-operating-capacity machines lift up and haul away the concrete debris using bucket attachments.

"The number of skid-steer loaders utilized on the job site depends on the phase of demolition that we're doing," says O'Keefe. "I would say that we use up to a half-dozen Bobcat skid-steer loaders out there at any given time."

Precision Demolition

Bobcat skid-steer loaders are chosen for this type of demolition project for a few reasons — their compact size, versatility and durability. The compact size of the S300 and hydraulic breaker attachment provides operators more control, enabling them to perform more precise demolition, O'Keefe says. This is especially important when working in highly congested areas where containing debris creates a major concern.

"With the skid-steer loaders, you have a lot more control over the work that you're doing and they do a cleaner job," he says. "They help prevent debris from going outside the work area."

The skid-steer loaders' size and versatility are also beneficial on similar demolition projects. Oftentimes, Brandenburg crews use the loaders to access the inside of buildings so that they can perform interior demolition before completely tearing them down. Their light weight also enables crews to easily place them atop multi-story structures without worry of a collapse.

At the Chicago Skyway job site, a few larger portions of the project have required bigger machines. However, O'Keefe says a majority of the demolition is completed with the Bobcat S300 skid-steer loaders and hydraulic breaker attachments.

The skid-steer loaders also help with sorting and hauling the concrete debris. Nearly all of the concrete debris is recycled once it's separated from the rebar and other obstructions. O'Keefe says some of the concrete chunks are used as banking material and others get crushed and reused as a subbase.

Getting In And Out

As soon as Brandenburg crews finishing demolishing a designated portion of the Chicago Skyway, it's time for them to move out of the area so that another contractor can come in. O'Keefe says Brandenburg managers have to work closely with the construction company so that their schedules coincide and not a day is lost. "We have to come in and complete sections as quickly as possible so that they can come in and re-pour the concrete," he says.

And when contending with the high volume of daily traffic on the Chicago Skyway, staying on top of scheduling becomes even more critical. Major roadway projects such as this one endure some of the strictest time constraints. If the project isn't completed by deadline, then the contractors face penalties for the additional time that the construction disrupts motorists and the rest of the public.