Located on the Ohio River, approximately 40 miles east of Cincinnati at Foster, Kentucky, the Meldahl Project includes a 105 megawatt "run-of-the-river" hydroelectric plant. The challenge was to deliver this monumental project efficiently on an aggressive three-month schedule. As such, Doka was hired by Baker Concrete Construction to meet the challenge.
The project design called for three, horizontal draft tubes with a conical shape starting with an approximate diameter of 36’-6” and transitioning into a rectangle at 59’ x 54’, with a total length of 91’-9”. Doka combined the efforts of their Chicago and Baltimore branches to meet these close tolerances and ensure the project was completed on time. Construction of the draft tubes began using Top 50 Formwork, a loose form system constructed from standard parts that can be assembled in any configuration for a wide range of applications. To allow for concrete to be placed faster, (522) pre-assembled, conical Top 50 gangs were delivered onsite and ready for immediate installation.
All Top 50 gang formwork that form the interior conical shape of the draft tubes were built and preassembled at Doka’s facility in Channahon, IL.
Doka’s experienced staff and state of the art carpentry shop worked day and night to construct all 522 individual gangs. Since each gang had a specific shape and location within the tube, all were individually numbered and shipped according to its pour ID number to provide maximum efficiency at the jobsite.
A grill of walers and beams was first dimensioned and assembled for each gang, then, the CNC machine shaping timbers were constructed to precise dimensions and attached to each grill along with a plywood form face. Next, the gang was labeled and the plywood face was covered with plastic for storage in Doka’s yard to provide quality and just-in-time delivery at the jobsite.
Load-bearing Tower Staxo 100
Doka’s Staxo 100 shoring was installed prior to the roof formwork assembly. This high performance, load-bearing tower is quick and easy to assemble and can be completed in a variety of ways to fit a wide range of field conditions. In addition, the flexibility of the system allows for maximum optimization of equipment and a reduction in necessary material. One million pounds of Staxo 100 Shoring was delivered and allowed for onsite pre-assembly for each level and segment.
"Staxo shoring is the safest system that I have ever used. The built in ladder, tie-offs and horizontal cross bracing make it a good system," said Kirt Inscho, superintendent, Baker Concrete Construction.
Staying on Schedule
To meet the demanding construction schedule, nearly 80 truckloads of Top 50 and Staxo 100 were delivered in total. To ensure safety on the jobsite, Doka’s field service was provided to educate and assist the crew on proper assembly of both Top 50 and Staxo 100.
"Doka's on-site field support was important to the success of this project,” said Inscho.
According to Michael Schaeffer, National Sales Manager, Doka’s experience on the Cannelton Hydroelectric Project assisted in the success of this project.
The Meldahl Project represents a significant economic development investment for the local community. More than 400 construction jobs were created for a variety of trade workers. The project is slated for commercial operation in 2014.