What supported old wall? Turns out, not much
As in a medical autopsy, construction workers learned why Indiana’s old Water Street retaining wall and Vinegar Hill steps had reached the end of their useful lives by tearing them apart.
A demolition crew several weeks ago began dismantling the leaning wall and the crumbing steps, believed to be a century or more old.
“There was not enough footer under it,” Alan Neeper said of the old wall. Neeper is a project superintendent for Francis J. Palo Inc., the Clarion-based company building a new retaining wall and an elaborate new stairway leading from Water Street to the hilltop residential neighborhood where film star Jimmy Stewart grew up.
“The concrete was not in real good shape. It didn’t take much to knock it down,” Neeper also said.
The workers discovered there was no footer under the old steps or the walls along the sides of the steps, and they found very few reinforcement bars embedded in the old concrete. And there was no drain for the water that collected in the steep hillside behind the wall.
Neeper said the old wall — which had been leaning toward Water Street for years — probably would have eventually toppled.
So what’s being done to make sure the $1 million-plus new wall and stairs will not suffer the same fate?
First, Neeper said, the footer being built under the new wall is much wider, 4 to 8 feet wide compared to about 2 feet for the previous footer.
Secondly, the new wall has a key along its bottom edge that fits into a slot 1 to 3 feet deep in the stone below the new footer.
Lots of rebar, at about 1-foot intervals, runs vertically and horizontally through the concrete of the new retaining wall and the walls beside the steps. The rebar is epoxy-coated to inhibit rust.
And a 6-inch drain was installed under the footer and a larger drain was placed horizontally in the hillside behind the new wall to channel away water that would otherwise press against the wall.
Plus, there have been advancements in concrete itself, Neeper said. Today’s concrete is more uniform in consistency than concrete mixed a century ago.
Other technological advancements in construction are also helping. Builders 100 years ago probably relied on strings and plumb bobs to align and level the old wall and steps, Neeper said. But the Palo workers are using an electronic distance measurement device with a laser to precisely plot points along the edges of the new structures.
The new wall is 18ﾾ inches thick and about 12 feet high at its tallest point. An estimated 800 cubic yards of concrete — more than the amount needed for some bridges Palo has built — will be needed to complete the new wall and stairs. Pouring of concrete for the new stairway began Wednesday.
Kevin Gruver, a Palo foreman, said it takes only a few hours to pour the concrete for some sections of the new stairway, but days were spent preparing the site, building forms and tying in rebar.
“Everything has to be very well-timed” during the concrete-pouring process, he said.
Ninety trees first had to be removed from the steep slope above and behind the old wall before demolition started.
“It took a week just to cut the trees,” Neeper said.
“The wall’s the easy part” of the project, Neeper added. In his opinion, the stairway of 69 steps leading up to Vinegar Hill is the real challenge.
And it’s the most decorative project Neeper has worked on. Bridges tend to be more utilitarian in appearance, but the new stairway to Vinegar Hill will feature brick inlays, columns with cast stone caps, decorative lights and a curved concrete wall and ornamental fence at the top.
The new wall and steps were originally scheduled for completion next spring, but Neeper said if the weather remains favorable the project may be finished by Thanksgiving.
At the same time, a crew of about seven workers from another Clarion contracting company, M&B Services, is forging ahead with a separate, but companion, project — another round of improvements under the Indiana Economic Development Project (commonly referred to as the streetscape enhancements) along North Seventh Street between Philadelphia Street and Water Street.
As in other blocks of the downtown that received improvements under the ongoing revitalization project, North Seventh is getting new sidewalks, street curbs, decorative lights and new trees. The street will be repaved and some utilities are being moved underground.
Part of the block is also being converted to a “people place,” a pedestrian gathering area that will be furnished with benches and tables.
The block will also feature 6,150 square feet of brick pavers — about 15,000 bricks — embedded in the new sidewalks.
North Seventh Street in that block will have two 12-foot-wide vehicle lanes, one northbound and one southbound.
Bryan Kiskadden, the M&B Services site foreman, said a final component of the project will be the erection of a 19-foot-tall arch over the entrance to North Seventh from Philadelphia Street. A sign on the arch will proclaim the people-gathering space as “IRMC Park.” Indiana Regional Medical Center bought the naming rights to the pedestrian plaza in 2008.
Kiskadden said generally good weather has also allowed the North Seventh streetscape enhancements to progress ahead of schedule. He estimates the work may be finished in September.
C.J. Onyak, an engineer and project manager with EG&G, an Akron, Ohio-based firm designing the streetscape enhancements and helping to secure funding for the project as a public-private partnership, said the retaining wall, new steps and lighting and landscaping along North Seventh Street will cost $1,606,286. The North Seventh Street enhancements (other than the lighting and landscaping) will cost $932,591.
Still to come in the ongoing streetscape improvements is Phase C , the fourth and final part of the project. It will encompass the 600, 700, and 800 blocks of Philadelphia Street. Improvements in those blocks likely will not start until 2014 or later.