Design-Build Turns an Emergency Repair Into a Long-Term Benefit

Solution

Using a two-phase design-build approach, our team began the project by inspecting the tank and collaborating with the city and a contractor to develop three potential solutions with pricing estimates: replace the tank; fix the floor by pouring concrete over the top of the existing surface; or repair the tank with updated structural components to help avoid future issues. Although the first two solutions may have been easier options, Harrisonville chose to update the structure of the tank to best meet its long-term needs.

Once the solution and guaranteed maximum price were set, our team set the timeline to complete phase two: design and construct the tank repairs. We removed the failed floor and excavated a few more feet into the ground’s surface. Before laying new concrete, clean gravel and drain tile made of black corrugated pipe was layered underneath the entire tank with a stand pipe at one end. This extra design function allows Harrisonville to test groundwater levels before draining the tank in the future, and even pump the groundwater down if the level is too high.

In addition to increasing the efficiency of the failed tank, our team installed a dozen piezometers surrounding all tanks on site so Harrisonville can take a reading of the groundwater level at any time. This added measure helps further mitigate the risk of future damage, keeping the tanks in working order.

Result

The project was completed July 2016, on time and $50,000 under budget. By using design-build project delivery, our team was able to design and construct the necessary repairs and upgrades to the tank in parallel, saving Harrisonville approximately 4-6 months on their emergency project compared to the standard design-bid-build model.