Upper Sandusky, OH
Award: Durability
Project Team:
Owner: City of Upper Sandusky Ohio
Contractor: Shook Construction
Engineer: AECOM
Concrete: Buckeye Ready-Mix, LLC
Slag Cement: Votorantim St Marys Cement LLC
This project involves construction of a new 10 million gal./day (38 million L/day) water reclamation facility (also known as wastewater treatment plant) for the City of Upper Sandusky, Ohio. This new facility features cast-in-place concrete structures including Sequencing Batch Reactor (SBR) tanks 1-4, Chemical Feed/Blower Building, Tertiary Filter Building, Cascade Aerator, Dump Pad, Administration Building, and Headworks. In addition, the concrete floor in an existing garage was replaced allowing this structure to be converted to a new screw press building. The project consisted of approximately 15,000 ft2 (1400 m2) of 8 in. (203 mm) thick concrete pavement and various sidewalks and stoops. This facility replaces their existing antiquated plant. This new plant provides a superior level of treatment compared to the old plant, resulting in much cleaner water being discharged into the Sandusky River.
A unique aspect of this project was that the new Headworks Structure that was 50 ft (15 m) deep in the ground. The mass concrete foundation of this structure was 4 ft (1.2 m) thick and the lower section walls were 3 ft (0.9 m) thick. Working at this depth presented challenges in groundwater mitigation, earth retention/shoring systems, as well as material and concrete conveyance to the bottom.
This project consisted of several mass concrete components. For example, the foundations at the Headworks Structure were 4 ft thick. Furthermore, nearly all of the concrete structures built contain wastewater as part of the treatment process. Slag cement is an excellent means for mitigating the potential for sulfate attack by reducing permeability. All tanks must be leak tested and no leaking whatsoever is allowed. The concrete supplied on this project resulted in almost no leaking. The handful of seeping shrinkage cracks encountered was patched with minimal effort. For a project this size, and with the amount of tankage constructed and tested, the minor amount of repairs required to stop leaks was superb.
The concrete used on this project performed extraordinarily well. On municipal projects such as this, strength is always extremely important. Nearly all of the concrete furnished was a 4500 psi (31 MPa) design. Approximately 6500 yd3 (5000 m3) of ready mixed concrete was placed, and there was not one 28-day break that failed to meet design strength. Moreover, 90% of the time design strength was exceeded at the 7-day break. The strength of the ready mixed concrete will lead to extended durability of these structures as well as an extended life cycle.
Appearance is also important. Many of these tanks can be seen from the public road in front of this facility. Consistency of color was very much a priority. The ready mixed concrete supplied on this project met all expectations and provided consistent color and appearance throughout. Aesthetically, the end result could not be better.
This project is the single largest capital improvement project in the history of the City of Upper Sandusky Ohio. That comes more into focus when you consider that Upper Sandusky is the county seat. This is a complete replacement of its existing wastewater treatment plant. The new facility more than triples the treatment capacity of the old plant, ensuring room for community and industrial growth. The end result of this project is substantially less waste making its way into the surrounding environment, and a higher quality of water being discharged to the Sandusky River.