Murfreesboro City Engineer Chris Griffith responds to questions that were phoned-in to Mayor Shane McFarland while he was on the WGNS' Action Line broadcast on December 10th.

1) We've reviewed the three bridges mentioned on WGNS for possible repairs. Brad Beavers directed Hoover to repave the approaches to the Thompson Lane bridge and it was completed last week. Both the Medical Center Parkway and Church Street bridges were evaluated and it was decided not to repave them at this time but continue to monitor them over the holidays and winter until the asphalt plants reopen.

We evaluated other alternatives instead of repaving the approaches including excavating and replacement of the approaches and pressure grouting the slabs. However, differential settlement continues to occur due to the difference in the foundation of the road (compacted fill) and bridge (deep foundations). This is a problem at many locations in middle Tennessee due to the geology. Roads are typically founded on fill which has settlement over time and bridges are founded on bedrock or deep foundations that have very little settlement. We have used some different construction
methods/materials over the last several years which has given us better results on more recent bridges.

We'll continue to monitor Medical Center Parkway and Church Street. Our best option seems to be repaving the approaches until the differential settlement slows.

2) The water taps on Bridge Avenue are rough and need to be reset. We'll schedule that work after traffic subsides and hot asphalt mix is available after the holidays.

3) We typically don't use water tables through intersections any longer but there are a few locations where they are helpful. Haynes Drive doesn't have much of a drainage system and is a mix of roadside ditches and curb and gutter but not much in the way of a true closed system which we use today. A complete overhaul of the drainage system converting it to a closed system would be helpful along the entire route. While we didn't notice any scarring of the paving at the locations, we'll evaluate them further with different types of cars to determine if further work is needed.