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Project of the Year: 2008

Cicero Ave Bridge

over the North Branch of the Chicago River

Location: Chicago, IL - Cicero Ave. north of Foster (approx. 5400N)

Approximate Value: >$100,000

Scope: Furnish and install fascia (skirt) panels on a new bridge.

Challenges: We were required to use the exact same ashlar stone formliner as used for the cast-in-place, but we were arched, not rectilinear. In order to keep the costs of the expensive formliner reasonable we had to carefully map out sequences of cutting and re-using pieces. Secondly we had to design connections. We refused to quote installation using the connections in the contract (see first photo) as the tolerances were so tight we could not be confident of properly aligning panels. Lastly, the erector had to figure out how to handle the panels so they'd both hang reasonably plumb and tuck under the bridge.

It all worked out beautifully. The erector's lifting jig worked great, the connection provided sufficient adjustment, and the way we covered up the connection points made it virtually invisible.

Architect:

General Contractor: Illinois Constructors Corp. Jim Carson (630) 232-7280

Click a photo below for a larger version:

Our starting point was hanging off the bottom of the deck. The 1/16th tolerance on locating the inserts is problematic because of cumulative tolerances.  There were 2 bolts/hanger and 3 hangers per panel. In real life it means each insert can be correct (within 1/16th) but the system won't work. There will be fit problems - either trouble getting a panel in at all, or lacking enough adjustment so it can fit nicely in line with its neighbor. We considered the risk of running into various problems to be unmanageable. We'd have to quote all sorts of contingencies which we might not need and we could not be confident we could do an acceptable job. So we quoted installation contingent on using our own connection design.Three of us (Leo, the erector, and an engineer) batted around a bunch of different ideas and eventually came up with an approach we liked. It worked beautifully. It offered adjustment, even after setting, so that if you had an alignment problem with the subsequent panel, you could adjust the prior panel.  You could unhook from the crane before committing to a final locationThe load connection before being patched in. We made little plugs from the formliner to cover the hole.The bridge that was being replaced was +/- 50 years old and had been cast in place concrete with a stone veneer. IDOT wanted to replicate but not duplicate the In the lower far right you can see the first panel installed on that side.   Above the panel you see bridge deck and then the cast-in-place formliner. We used an identical formliner.Because the panels hang from the underside of the deck you cannot lift from the top edge as you usually would.  The erector designed a lifting cradle that was perfectly balanced and kept the panels plumb.Here comes the next panel. Completed job.