Richland Chambers Pipeline Lowering – Tarrant Regional Water District

Rice, Texas

During the design of IPL Section 15-1, LAN prepared an expedited design to lower the Tarrant Regional Water District’s (TRWD) 90-inch diameter Richland-Chambers pipeline to accommodate future IPL construction. The pipeline could only be taken out of service for 45 calendar days, as a longer duration would jeopardize the ability of TRWD to serve customers. LAN worked with TRWD to evaluate six alternative pipe profiles and ultimately, recommended the replacement of approximately 1,600 LF of Prestressed Concrete Cylinder Pipe (PCCP) with new welded steel pipe. Only a portion of this length was necessary to accommodate the future IPL construction with the remainder necessary to avoid the transfer of thrust loads to the existing PCCP line.

The project was bid as a Construction Manager at Risk (CMAR) delivery with TRWD purchasing all pipe material in advance. The design was completed in less than three months and construction was successfully completed in 38 calendar days (15% ahead of schedule) and more than 10% under budget.

At a glance

1,540 LF of 90-inch diameter pipeline was relocated in less than 45 days

Uncoated, cement mortar lined steel pipe was used for the new installation

The depth of cover in some areas of the lowering exceeded 25-feet

No more than 45-days was permitted for construction in order to maintain contracted raw water service

The pipe material was pre-purchased by the Owner to minimize the risk for delays in delivery

The project was bid and constructed under a Construction Manager At Risk (CMAR) contract

By encasing steel pipe in concrete, an alkaline environment similar to the existing prestressed concrete cylinder pipeline was maintained

Construction cost was reduced in part by negotiating an alternate access point requiring less site work

Features

The pressure reducing interconnection at the Richland-Chambers pipeline crossing was architecturally designed to mimic other above ground barns/structures in the area to blend with the landscape

Design efforts included proactive stakeholder engagement with local officials, including Navarro County, the Navarro County Electrical Cooperative, and two local water supply corporations

The preliminary design included a detailed evaluation of likely construction access routes, including consideration of load ratings for bridges needed to deliver goods

Development of the Richland-Chambers interconnection site required design of improvements to an unpaved county road to ensure all-weather access could be provided

The awarded contractor elected to utilize three pipe laying crews during construction, cutting construction from a budgeted 24 months to approximately 15

Services

Pipelines

Client

Tarrant Regional Water District

Related Work

Pipelines

Water Supply and Transmission