Delhi Dam Construction Progress Report #5
July 24, 2014
General Project Information
Phase 1 was awarded to Lunda Construction Company in April 2014.
The DNR permit allowing the entire project to be constructed including Phase 2 has been received clearing the way to complete the project.
The important critical goal of Phase 1 work is to complete enough refurbishing work on the concrete structure to allow river water flow to be diverted from the current river bed through the concrete structure.
We are now reasonably confident that Phase 1 work will be substantially complete by October 2014 allowing for the river to be diverted through the refurbished concrete structure. Therefore, the Trustees at a meeting on July 24, 2014, approved going out for bids the week of July 28, 2014. Bid period will be four weeks and with a week or so to evaluate the bids, the work on Phase 2 will mobilize in early September.
Project completion date is dependent on several factors including river flows being average or below, few weather extremes in the next 12 months, selecting a quality contractor for Phase 2 equivalent to our Phase 1 contractor and finally that the flow in the river at the time needed to refill the lake is sufficient.
Right now, again for planning purposes, we are planning for a July 4, 2015, date to resume enjoyment of Lake Delhi. It could be ready sooner if everything listed above goes great.
Specific Progress by Lunda on Phase 1 work through July 8, 2014 includes:
River flows are returning to more normal summer flows and have been at average flows. This high river flow has slowed work on the project due to flooding of the upstream and downstream cofferdam areas.
The upstream cofferdam has been strengthened to reduce leakage to a tolerable amount allowing work to proceed on upstream side of work area.
Saw cutting continues on pier removal. Here workman is making a vertical cut with his 4 foot diameter saw. You can see the gray saw blade protected by a large shield with the workman behind. You can also see the beginning of the horizontal cut mid way down n the lier. The saw rides on tracks attached to the concrete pier.
Work returns to the upstream side following cofferdam fixes. Here the rebar is being installed and the wooden forms are being place to allow the anchor block to be filled with concrete. This is required to meet Corps of Engineers permit stability requirements.
Pumping concrete into anchor block form. Top picture is concrete pump on top of spillway. Bottom picture is the large anchor block being poured in one operation. This is one of the largest pours for Phase 1, over 60 cubic yards of concrete.
Finally, View from downstream side taken July 24, 2014 showing workman on upstream side preparing to remove concrete on the bottom of the spillway opening. Also, you can see water flowing through the two openings midway down the spilway. These are the functioning 37 inch diameter tubes connecting the upstream and downstream areas on teh work area. This is how the contractor is able to manage the upstream cofferdam leakage by allowing it to flow out through these two tubes. These tubes were also used in 1928 when the original structure was first built.
Work Progress through July 24, 2014
Lunda has poured Rock Anchor Block north of Sluice Gates. Concrete sawing for pier removal is approximately 80% complete. Lunda has removed all but the bottom 6.5 ft. of the north and south Pier Noses.
The Concrete Condition Survey on the Spillways and Spillway walls continues.
Lunda continues to install sheet pile shoring at the northwest corner of the Powerhouse.
Lunda’s priorities are as follows:
Continue Pier Nose removals, saw cut concrete at abutment walls, and begin demo & rehab on spillway walls following the Concrete Condition Survey for the spillway walls.
Setting Tie-backs for shoring at the NW corner of the dam..
Continue dewatering. Complete pouring Rock Anchor Block.
Begin Rock Anchor Foundation Grouting.
Next Dam Construction Report – Thursday, August 13, 2014
Pat Colgan