CHICAGO (WLS) -- Crews will soon begin the final phase of the Lakefront Trail, and as part of that, they will add a tunnel through two historic bridge houses along Lake Shore Drive.
The Lakefront Trail is far easier now to navigate with separate lanes for those on bike and those on foot. The new Navy Pier flyover removed dangerous street crossings.
But, there remains a bottleneck when the trail reaches the Lake Shore Drive Bridge. At that point, the trail must pinch onto a narrow sidewalk.
To make more space, they have to tunnel through the old bridge houses.
"We'll be removing the limestone very carefully with masons cutting an opening in the existing masonry, and constructing a pathway through the first floor of the existing house," said Dan Burke, chief engineer for the Chicago Department Of Transportation (CDOT).
It's not a simple project.
The bridge houses are 82 years old. The exterior is limestone blocks, weighing about 300 pounds each. And each will be individually removed. Inside the south house, all the electronics that control bridge lifting will have to be moved to a higher floor.
When done, it will be 16 feet wide with lanes for those on foot and on bikes. It will be much easier to navigate. And in a sense, trail users will be passing through history.
"Now this is adding a new element to it and letting people feel the infrastructure and appreciate what it takes to get them across the river," said Rebekah Scheinfeld, commissioner of the Chicago Department of Transportation.
The project is expected to be completed by the end of 2019.
Apart from the flyover work, the bridge itself is about ready to undergo a major renovation.
It's been 32 years since the LSD bridge last underwent significant work. From its giant gearing below, it works fine, but its road surface and structural supports need $25 million worth of work.
"Drivers should expect to see lane closures working in quadrants on the bridge going clockwise fashion and will be starting with lane closures in the southbound lanes of traffic first," Scheinfeld said.
Closures are set to begin this week with work continuing into the spring of next year. By then, barring delay, trail users will pass through new bridge house tunnels.