The Line J, Section 1 Pipeline is a 2.29-mile, 108-inch diameter, welded steel pipeline. It connects Tarrant Regional Water District’s (TRWD’s) existing balancing reservoirs directly to the District’s new hydrogenation facility, currently being constructed, and removes the Arlington Outlet demand from the existing pipelines, which allows the existing pipelines to deliver more water to the Rolling Hills Water Treatment Plant until the Integrated Pipeline is completed.
To meet schedule requirements, TRWD, Garney Companies, Inc., and Freese and Nichols, Inc. divided the design and bids into six packages: pre-purchase of multiple 108-, 84- and 48-inch butterfly valves, procurement of 108- and 84-inch tee fittings, installation of fittings in existing 84- and 108-inch parallel prestressed concrete cylinder pipelines (PCCPs), pre-purchase of pipe from four manufacturers, 135 feet of 133-inch diameter tunnels, and pipe and valve installation.
Line J is the first pipeline to be recognized by the Envision™ Sustainable Infrastructure Rating System, earning a Silver Award in August 2014. It addresses aspects of sustainability in a number of ways. Most relevant is the use of native materials as the aggregate in controlled low strength material (CLSM) embedment.
Since the CLSM is backfilled before it reaches its 28-day strength, multiple lab tests and one field test were performed to determine its strength at days one, three, five, seven and 28. “Kelly Ball” drops and probe penetrometer readings were also collected to correlate the unconfined compressive strength to inches of deformation caused by the Kelly Ball and resistance to the probe. These measurements were taken for future use in the field to indicate when the CLSM has gained enough strength to be backfilled. Finite element models were also run to determine deflection caused by backfilling with various CLSM strengths. The modeling was possible due to studies completed by the University of Texas at Arlington.
Other aspects of sustainability include streambank restoration and stabilization, meetings with city officials to minimize the impact of road closures and preparing traffic control plans.