From
Patricia D. B. Redfearn, Ph.D.
Title
Ratify Change Order No. 2 with Tri-Con Works LLC increasing the contract amount by $49,740 to provide for emergency repairs to the leachate collection system and force main associated with the Gas Control and Collection System located at Grand Prairie Landfill for a total of $1,003,809.95
Presenter
James R. Cummings, Environmental Services Director
Recommended Action
Approve
Analysis
The City of Grand Prairie landfill has had a gas control and collection system in place since 2000. During that time, waste deposition has increased in lifts requiring wells to be raised. The system has aged and has periodically been repaired and improved. This project, which commenced in December 2017, is providing for the replacement of pinched off wells, an increase to the current density of the well-field, a new, larger header, lateral piping, condensate pumps, isolation valves and placement of a new flare skid.
During the massive excavation that has been required to complete this large project, two additional problems have been identified. One was a crack in a large T connection, which required additional excavation, waste removal, parts and repair, resulting in a $7,900 change order, which was approved by the City Managers Office on April 9, 2018. The second is the discovery of leachate force main failures, which have resulted in emergency de-watering efforts undertaken by landfill staff for the past several weeks. The most cost-effective solution to this problem is to run 6,000 feet of leachate force main from the headwall to the leachate riser. This change order will cost $49,740, bringing the total for change orders to this project up to $57,640 requiring Council ratification.
Contract History Change Amount Total Amount Reasoning
-Change Order No. 1 $7,900.00 $954,069.95 T Connection crack repairs
-Change Order No. 2 $49,740.00 $1,003,809.95 Leachate system emergency repairs
Financial Consideration
Fundin...
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