STRATEGIC PRIORITY: Transportation & Infrastructure
AGENDA DATE: August 9, 2023
COUNCIL DISTRICT(S):|910|DEPARTMENT: Water Utilities Department
EXECUTIVE: Kimberly Bizor Tolbert
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SUBJECT
Title
Authorize an increase in the construction services contract with Thalle Construction Company, Inc. for additional work associated with the installation of a 120-inch diameter wastewater interceptor on Riverfront Boulevard - Not to exceed $2,097,576.08, from $30,393,551.50 to $32,491,127.58 - Financing: Wastewater Construction Fund ($1,500,000.00) and Wastewater Capital Improvement F Fund ($597,576.08)
Body
BACKGROUND
The Dallas Water Utilities (DWU) Lower East Bank Interceptor project at Riverfront Boulevard / Market Center Boulevard from Woodall Rodgers Freeway north to Stemmons Freeway Service Road is currently under construction. The project includes the installation of 8,400 feet of 120-inch, 104-inch and 84-inch diameter wastewater pipeline to replace a deteriorated 1940s era concrete pipeline. These improvements will increase wastewater capacity for future development and address existing infrastructure in poor structural condition.
At the east side of Riverfront Boulevard just north of Woodall Rodgers, a portion of the new 120-inch diameter pipeline was proposed to be constructed beneath an existing double barrel pressurized 10-foot by 9-foot stormwater box culvert. Upon further field investigation, the contractor exposed the 10-foot by 9-foot double barrel storm sewer and found that it had an additional layer of concrete which reduced the clearance below the storm sewer. This unforeseen condition resulted in a conflict with the proposed pipe crossing. In addition, the contractor discovered unstable soil conditions with higher groundwater levels causing constructability challenges. Since the preconstruction geotechnical borings were spaced incrementally along the alignment, the unstable soi...
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