Photograph courtesy of Ohio Division of Herbal Sources
The Ohio Division of Herbal Sources (ODNR) is overseeing the $24 million enterprise to exchange the historical McConnelsville Dam.
As a way to maintain the historical Muskingum Freeway lock and dam gadget and make allowance for persisted leisure navigation, crews in Morgan County, Ohio, are changing the historical McConnelsville Dam. The Ohio Division of Herbal Sources (ODNR) is overseeing the $24 million enterprise.
Photograph courtesy of Ohio Division of Herbal Sources
“There were a number of upkeep to the sheet pile construction, together with period in-between enhancements to stabilize the best abutment,” mentioned James Hilovsky, a crew lead of ODNR’s department of engineering. “General, the present mobile sheet pile dam is in deficient situation past its serviceable lifespan, and wanting alternative.”
Web page paintings and preparation started previous this yr, with water paintings beginning in June. The undertaking is predicted to be finished in 3 summer season development seasons.
“We’re recently within the first segment, which incorporates development of the left and proper abutments and a portion of the brand new dam ranging from the left abutment. The remainder sections of the dam shall be built in the second one season, and the present dam elimination and different website online paintings finished within the 3rd season.”
The brand new construction shall be roughly 580 toes. downstream of the present dam.
“The unique dam used to be built in 1841 and used to be identical in nature to lots of the different dams alongside the river which can be rock-filled bushes crib constructions, later capped with concrete. The unique McConnelsville Dam failed within the past due Forties and used to be changed with the sheet pile construction recently in provider lately.”
The dams alongside the Muskingum River are thought to be important to keeping up the leisure navigation during the lock gadget. There are also miles of coastline, docks, bridges and different infrastructure that depend at the water ranges maintained via those dams. “It is a very powerful to make sure those dams are maintained in a protected situation so as to give protection to the existence and belongings upstream and downstream of the constructions,” Hilovsky mentioned.
“Because the gadget approaches 200 years previous, it has develop into an important a part of the identification of the communities that encompass it. The gadget is situated within the middle of Appalachian Ohio, and the investments which can be being made within the gadget lead to alternatives for development jobs, subject material and kit provide and alternatives for more than a few strong point subcontractors to participate in a historical rehabilitation undertaking.”
The dam recently has a sheet pile vertical face. This new design may have a concrete stair step face which can supply a extra enjoyable glance. The design additionally has the additional benefit of bettering power dissipation and lowering the potential of unhealthy rollers to shape on the toe of the dam.
The Ruhlin Corporate used to be decided on as the development supervisor in peril (CMR). During the CMR supply way, Ruhlin has been ready to supply early enter on design ideas, constructability considerations, price estimates and scheduling. Additionally they were ready to pre-qualify subcontractors to make sure essentially the most certified subcontractors are to be had to finish the paintings.
Photograph courtesy of Ohio Division of Herbal Sources
The present dam, built in 1841 and reconstructed in 1959, is roughly 14 toes. in top with a 192-ft.-wide primary spillway and a 394-ft.-wide secondary overflow. It’s regulated via the ODNR Dam Protection Program as a Elegance II construction. The alternative dam used to be designed via Michael Baker World, which is the engineer of document, offering development management products and services for the undertaking.
“Essentially the most difficult facet of this undertaking is operating at the Muskingum River,” Hilovsky defined. “The undertaking has been phased to happen right through the traditionally decrease pool ranges, however the river can range considerably relying on rainfall.”
Paintings is recently underneath technique to assemble the drilled shaft abutment partitions, beginning at the left abutment and transferring subsequent to the best abutment. The contractor is also starting to position concrete for the in-water dam, together with the set up of a sheet pile cutoff wall within the canal embankment.
The rock causeway, abutment cofferdams and preliminary excavations for the abutments were finished. A short lived get entry to bridge additionally used to be put in around the canal to supply get entry to for the heavy apparatus and fabrics that wish to be dropped at the website online. Tree clearing and different website online arrangements have been finished earlier than development started in June.
Clearing the east riverbank of the Muskingum River incorporated disposing of timber and crops. Re-grading the canal embankment to create a piece platform for the abutment and get entry to to the causeway used to be additionally vital.
The stair stepped dam shall be poured in lifts. The primary lifts shall be positioned underwater by the use of tremie. As soon as the concrete construction is entire, put up pressure rock anchors shall be put in alongside the crest of the brand new dam to anchor to the river bedrock.
The present dam’s sheet pile cells shall be got rid of and the sand and gravel inside of those cells shall be left in position. Cells at the proper abutment will stay in position to assist in stabilizing the adjoining roadway embankment. Cells at the left abutment will stay in position and be transformed to a fishing pier. The present dam shall be demolished on the finish of development.
Hilovsky mentioned the main fear when surrounded via water is the protection of the crews operating within the river, in addition to coverage of the paintings.
“The causeway elevations have been moderately decided on to steadiness chance of overtopping and maximize operating days right through the summer time the usage of historic river elevations. The undertaking additionally used to be designed to deal with leisure get entry to during the canal and lock.”
Building of the abutments on every aspect of the dam permits for the geotechnical subcontractor to finish those scopes of labor with out mobilizing in next seasons. The everlasting enhancements are contained inside of ODNR belongings; on the other hand, the best abutment calls for a lane closure at the adjoining highway and ongoing repairs of visitors all the way through the undertaking.
Even if development is predicted to be finished via the top of 2026, this paintings is extremely dependent at the parts and river water ranges.
“Climate is at all times a consider dam development, particularly when operating within the river,” Hilovsky mentioned. “The undertaking has been phased to paintings right through the optimum season in line with previous historical past of the river, however the undertaking crew maintains a development tracking plan to make sure the crew is repeatedly tracking and ready to react to converting climate and water ranges.”
Photograph courtesy of Ohio Division of Herbal Sources
The fabrics getting used at the undertaking come with concrete, reinforcing metal, graded aggregates and earth-fill. The concrete combine has been designed particularly for this undertaking. Crews shall be putting a big amount of concrete underneath water by the use of a tremie.
Some of the apparatus on website online is a long-reach excavator.
“This system has the similar configuration as a normal excavator however has a for much longer increase and dipper keep on with give it an extended attain,” mentioned Hilovsky. “We are also the usage of an excavator with a drill attachment. This can be a very specialised piece of kit in a position to drilling deep cylindrical shafts in earth and rock. This is very important to build the soldier pile partitions for each abutments.”
Hilovsky praised the design and allowing partnership with Ohio EPA, US Military Corps of Engineers, Ohio State Ancient Preservation Place of work and Morgan County, and underscored the hassle is a primary of its sort in fresh ODNR historical past.
“The Muskingum River Freeway is a singular gadget that has been in provider for the reason that 1840s. That is a surprisingly necessary undertaking to lend a hand maintain the program and make allowance long term generations to proceed to revel in this piece of historical past.” CEG
