Concrete Reservoir R1A Analysis and Improvements

• Owner: Walnut Valley Water District
• Cost: $1,450,000

Progressive sagging and cracking of the existing concrete roof slab and corrosion of reinforcing steel on walls and columns of this 8.0 MG partially buried concrete reservoir demanded detailed analyses and evaluations to determine potential causes of the problems and corrective measures.

Perliter & Ingalsbe provided a full range of engineering services including engineering analyses and evaluations, preliminary and final design of the proposed improvements, bidding services, construction management, and continuous inspection.

Major Components and Special Features:

Analyses and Evaluations:

• In the first phase analyses and evaluations were made to assess the existing condition of the reservoir, including roof failure and corrosion of reinforcement.
• Alternate repair methods were developed and evaluated to strengthen the existing reservoir roof structure through detailed structural and seismic analyses. It was decided to remove only a portion of the roof slab, leaving the columns and 8-foot by 8-foot sections of the roof intact at each column and placing a new concrete roof slab on top.
• Alternate methods were developed and evaluated to rectify reinforcement corrosion. Removal of corroded reinforcement, adding new reinforcement, and applying shotcrete were recommended.
• Improvements to reservoir appurtenances, piping, electrical system, communication system, instrumentation, and general site features were recommended.

Structural Improvements:

• Partial removal of concrete roof slab
• Placement of new concrete roof slab
• Removing corroded reinforcement and placing new reinforcement on walls and columns
• Applying shotcrete on walls and columns
• Repairing cracks

Other Improvements:

• Yard piping modifications
• Installation of new instrumentation and controls
• Electrical and communication systems modifications
• Removal replacement of ac pavement, concrete curb, and gutter
• Placing new aluminum handrail
• Painting of select items