Dam Construction Update August 14, 2014

Delhi Dam Construction Progress Report #6

August 14, 2014

General Project Information

Phase 1 was awarded to Lunda Construction Company in April 2014. An important goal of Phase 1 work is to complete enough refurbishing work on the existing concrete structure to allow river water flow to be diverted from the current river bed through the concrete structure. At the Trustees meeting on July 24, 2014, approval for going out for bids for Phase 2 work was made. Evaluation of overall project schedule is near completion to determine when the work will be bid for a fall start date for Phase 2.

Project completion date remains dependent on several factors including river flows being average or below, minimal weather extreme events in the next 12 months, selecting a quality contractor for Phase 2 and finally, that the flow in the river at the time needed to refill the lake is sufficient to refill. Also, consideration must be given to lake bed issues prior to refilling and startup procedures for the new flood gates as they will be fully loaded for the first time only after the lake is initially filled.

River flows have returned to below normal summer flows creating ideal construction conditions during the last several weeks.

Saw cutting on upstream piers removal is now complete.

Detailed view of demoltion work accomplished in first spillway bay. The far wall shows deteriorated concrete that has been removed exposing original reinforcing steel. Right side shows where the removed concrete pier had been. Below shows rock anchor block ready for installation of rock anchors. Overall demolition is nearing completion as the existing concrete is very strong and generally in great shape. Downside is that the tough concrete is difficult work to remove by hand equipment. Kudos to the workers!

Rock anchor drill in place to begin rock grouting and then installation of rock bolts required to meet permit stability requirements for the new faciity. Rock bolts will extend 40 feet into bed rock. Drill rig sits atop rock anchor block previously installed by Lunda. First hole was drilled on Wednesday, August 13. Rock bolting subcontractor is from Tennessee.

Rock drill rig needs a bath after one day of drilling (formerly yellow covered with dust).

Working on manlift to remove deteriorated surface concrete on the down stream side of spillway. Overall the majority of concrete surfaces has been inspected and the amount of demotion is understood which is less than originally anticipated.

Deep excavation on north side of the upstream side of the dam required to install the rock anchor block for eventually rock anchors.

Workers removing steel guides embedded in original conrete for an old flood gate. New guides will be embedded in new concrete piers to be placed in the coming weeks.

Work Progress through August 13, 2014

Review of work progress:

Lunda has completed installing, grouting and testing sheet pile shoring Tie-Backs at NW corner of Powerhouse.

 

  • Lunda has excavated for Rock Anchor Blocks at the Powerhouse section of the dam and has begun to roughen the face of the upstream dam walls for concrete bonding.

 

  • North and south Pier Noses have only the south bottom section that could not be saw cut, yet to remove by jackhammer.

 

  • Lunda and Stanley have completed the Concrete Condition Survey on the Spillways and Spillway walls.

 

  • More Concrete condition Survey is left to be completed on the Powerhouse and Tail Race wall below and to the north.

 

Project Schedules and Priorities:

 

  • To finish Pier Nose removals.

 

  • Finish demo & rehab on spillway walls.

 

  • Rock Anchor Foundation Grouting. Begin forming and placing rebar at new Pier Noses.

Next Dam Construction Report – Thursday, August 27, 2014

Pat Colgan

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