Clarksville, TN – Work continues to move forward on College Street repairs. The following is a Thursday, August 25th, update from Edwin Neely, Engineering Manager/Project Manager for contractor Fulton Wilson Construction:
We have progressed fairly well with the deep excavation and 66-inch diameter pipe installation since last week and have approximately 48 linear feet remaining to install as of this evening. One major milestone we met earlier this week was pipe installation and partial backfill past two AT&T duct banks that have dramatically slowed our production over the last few weeks.
Our deep excavation has been slowed further this past week by the discovery of three additional active sinkholes since my last update to you. We have completed repair of two and are in the process of addressing the third now. There has been significant rock excavation throughout the entire trench work.
Our current plans are to commence with earthen backfill above the crushed stone bedding from Junction Box No. 1 to the AT&T duct banks next week. This work will take approximately two working days to prepare and install (backfill) to the elevation necessary for reinstalling the affected shallow utilities such as water, sanitary sewer and gas. We have coordinated our plans for reconstruction of these shallow utilities with the Gas & Water Department.
Installation of Junction Box No. 2 is planned for Tuesday, however, it largely depends on the condition of subgrade (soil) we find during our remaining excavation. We are finding less rock excavation in our deep trenching, but this potentially poses another problem in that we expect to encounter significantly soft or otherwise unsuitable soils to a depth well below our proposed deep excavation.
Once we excavate the trench, we will make the necessary recommendations and repairs to the subgrade to continue with our pipe installation and backfill. I have already discussed potential solutions with both the Street Department and Gas and Water, and will likewise coordinate our recommendations to TDOT as well once we know more.
TDOT continues to be timely in furnishing the No. 57 stone and surge stone that we need for backfill just as previously discussed and agreed on in the Mayor’s Office. They are also cooperating with me fully in securing the other materials we discussed such as concrete, shallow storm drain pipe and precast junction boxes that are needed to complete the storm drain portion of the work.
The City of Clarksville’s traffic control and the onsite security seems to still be effective in minimizing unsafe access to the site by the public. With the commencement of classes with APSU and more nighttime activity in the area, we have decided to utilize the Clarksville Police Department for overnight security.
The Street Department makes daily site visits and is specifically involved with each sinkhole remediation. Gas and Water Engineering and Operations staff continues to be very helpful and accommodating to our schedule and needs. Gas and Water has also been helpful with conceptual planning for reinstatement of utilities and has provided timely decision-making.
This project continues to be the challenge in subgrade diversity that we expected. We hope to complete our deep excavation, 66-inch pipe installation and set the final junction box by mid-week next week. There is still a significant amount of shallow work that we must perform prior to reinstating the traffic signalization and TDOT paving. Shallow utilities should take approximately 10 days to complete and it is our hope and goal to have these completed by mid-September. This is obviously largely dependent on weather and any subgrade problems encountered.