Successful water plants

The Goal

To create a new concrete liner in an existing water treatment tank
During the expansion of the wastewater treatment plant, the existing secondary digester tank required a new concrete liner. Achieving this required the walls of the liner to be cast within the existing tank, which was nearly 30 feet tall and had a radius of 38’-9”.

The Project

Summary:
The MEVA design team overcame the unique challenges of this project to efficiently create the new liner using the MEVA Adjustable Radius (MAR) formwork.

Challenge:
The existing tank had a cone-shaped bottom, and the tank walls could not be used for tying the formwork to. This meant that careful consideration needed to be given regarding how to install the formwork on a sloping base and brace it adequately for such a large height.

The Solution

1. Pre-assembled formwork saves time and effort
   The MEVA Adjustable Radius (MAR) system was chosen as the radius formwork because of its time-saving benefits. The system was delivered to site in pre-assembled units with the radius already calibrated. In contrast, traditional formwork systems often arrive at the construction site in hundreds of pieces and require a lot of time, manpower, and parts to put together.

   Once on site, the contractor needed to merely remove the pre-assembled formwork from the truck and place it into position with a crane. This not only provided significant time savings, but also considerably reduced on-site labor costs.

   
    

2. Technical expertise for unique situations
   Since the existing walls were already poured, conventional ties could not be used. Instead, the MAR had to function as a one-sided wall form. The ties that were used were called she-bolts. Anchors were first drilled and then epoxied into the existing concrete walls. A one-foot length of Dywidag threaded rod was then secured to the anchor and threaded into the end of the she-bolt to overcome the tying issue.

   The first lift was approximately 14-feet tall. At the top of the first pour, the contractor installed an anchor into the new concrete to be used to secure the bottom of the wall formwork for the second lift. On the second lift, the forms ran above the wall, which allowed a dry tie to be installed to relieve some of the load. For additional bracing support and alignment with the first lift, MEVA R360 braces were used. The formwork also sat on regular bridge overhang brackets for further support.

The Outcome

The new, expanded wastewater treatment tank was delivered faster and easier than expected thanks to the pre-assembled MAR system and the technical expertise of the MEVA team.

Featured Products

• MEVA Adjustable Radius (MAR) system

Client:
Kirk Bros.

Owner:
Ohio Environmental Protection Agency

Project:
Wastewater Treatment Plant Expansion

Location:
Mansfield, Ohio

Engineering:
MEVA Formwork Systems, Inc.