Fast action expected on flume

Meanwhile, speculation is mounting over the cause of the collapse and some fingers are being pointed at recent work done for Shelbyville Power, Water and Sewerage System.

The council meets at 3 p.m. and will vote on hiring the original company that built the flume 47 years ago and a local firm to do the excavation work.

Who is responsible?

City manager Ed Craig said the city "does not know what happened, we can only speculate" over what occurred to the underground stormwater drainage system.

But he added that "you can not escape the possibility that the recent sewer work in the area has had an impact on the flume."

Several council members expressed that view as well, saying that the flume has had no problems for 47 years until the work was done on the adjoining sewer lines.

The work that begun last November involved re-laying a sewer line starting beside Dr. Charles Stimpson's veterinary clinic, engineer John Freeman of the utility said at the time.

The line was laid eastward under North Brittain Street and runs to Madison Street, where a directional bore went under the main thoroughfare, up to the west side of the old Fix-It Shop. After that, the sewer line crossed Jefferson Street to First Christian Church, where the work ended.

The sewer work was paid for with a Community Development Block Grant (CDBG), Freeman said. Last August, the Shelbyville City Council awarded the contract for the work to Mayse Construction Co. of Chattanooga, which had the low bid of $1,079,053.

Craig said he has spoken to David Crowell of Shelbyville Power and said the utility "is ready to do what they need to do." But Craig was hesitant to say whether the city or power company would end up footing the repair bill until more is known.

"It doesn't look like we did it, so we might want to be looking at Shelbyville Power and they need to be looking at their contractor," Craig said.

Also, the flume itself is deeded to the Shelbyville Housing Authority and not the city, Craig said. However, the city is still looking at other funding sources to pay for repairs, Craig said.

Crowell said Monday afternoon that until the utility received an engineering report about the flume, it would be inappropriate for him to comment.

How it happened

Craig said that the original firm that did the work on the flume in 1962-63 was called ARMCO, but the construction division of that company split off five years ago and became Contech.

The company still has the original presses to make the 47-year-old flume "and they are huge in this business," Craig said. "They can match what we need bolt for bolt because they built it in the first place."

An engineer for Contech speculates that water entered underneath the flume when the recent sewer work was done after "the back fill was not adequately compacted," Craig explained to the council.

With the recent heavy rains, "swirling" occurred around the flume and washed away material from the bottom corners of the pipe, which was described as the weakest point of the flume.

With all of the other pressure on the pipe, the water underneath it caused the flume to buckle upwards, Craig explained.

The 200 feet of damage is believed to extend between North Brittain to the middle of North Main Street. Craig said that the damage appears to be in the exact same area where the flume was exposed when Mayse Construction did its work on the sewer lines.

Public works director Mark Clanton also recently observed water pouring into the ground near the Rite Aid parking lot on North Brittain Street. This is where city officials speculate that the water entered the area around the flume.

The cost?

Craig said the estimated cost to fix the flume damage could run into the $400,000 to $500,000 range.

Contech has submitted a proposal to Shelbyville to fix the problem, estimated to cost $247,800 to supply the 200 feet of pipe and to assemble the structure.

However, those costs do not include boring, the structure removal, excavation, foundation preparation, backfill material, unloading material or labor.

An engineer with Contech will also look into what went wrong, Craig said.

Firm has ties to public works director

The Contech engineer recommended using local firm Clanton Excavating, because of familiarity and experience. Craig pointed out the public works director Mark Clanton is related to the owners of the firm, but said that Clanton Excavating was the engineer's request.

Also, since the scope of the work is not yet known, Craig said "there is no way we can bid on that, and we need to get this work done."

The fee for the excavation would be based on a time and material basis and the city can get a better price for rock and other materials, "to reduce the cost as much as possible," Craig said.

There are also concerns that more rain could cause further damage, which is why the city is rushing to get the work started. Craig said that for every 200 feet of pipe that is damaged, it could cost an extra half million dollars.

"We need to move with speed," Craig said.

Contech engineers told Craig as soon as the city gives the go-ahead, they could have the pipe on site within two weeks, which is how long it will take to have the excavation work completed.

The assembly would take three to four days and the process of putting in back fill could take five days, depending on the contractor's speed.

Work on the repairs could begin as soon as next Monday, but could be delayed due to weather.

A corrosion inspection was conducted five years ago and the flume was in good shape at that time, according to city officials. Also Clanton said he has inspected the flume "once or twice a year" as well.

Traffic concerns were also inquired about during the meeting, with Clanton saying that street closures are being handled by the police department.

Answering questions from council members about opening a single lane, Clanton said the situation with North Main was "just too dangerous" to allow that to happen.