Integrated Pipeline Project Richland-Chambers Pipeline Lowering
The Richland-Chambers Pipeline Lowering represented a critical first step in construction of the $2+ billion Integrated Pipeline Project (IPL), a 150 mile transmission pipeline collaboration between the Tarrant Regional Water District (TRWD) and Dallas Water Utilities to increase water supply in the Dallas/Fort Worth metroplex. To accommodate future construction and operation of a 108-inch raw water pipeline, Lockwood, Andrews & Newnam, Inc. (LAN) led design efforts to lower the existing 90-inch diameter Richland-Chambers pipeline. Design included evaluation of six separate vertical alignments to achieve a balance between protecting condition of the existing pipeline and meeting an aggressive construction schedule.
LAN developed a relocation design that could be constructed within an allowable 45-day maintenance window. During the winter of 2014, the pipeline was dewatered to accommodate the relocation of more than 1,500 LF of 90-inch pipeline with some bury depths in excess of 25-feet. Relocation was designed using 90-inch uncoated, cement mortar lined steel pipe encased in low strength concrete. With design completed more than one year before the allowable maintenance window, sufficient time was available to pre-purchase pipe material and avoid the risk of manufacturing and delivery delays during construction.
Ultimately, the project was successfully completed under a Construction Manager At Risk contract 18% ahead of schedule and 13% under budget without impacting future system operation, and the conflict with the proposed IPL line was eliminated.
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
Design considered six various profiles to account for thrust in various ways
Total thrust forces exceeded 1,000,000 pounds in the relocated pipeline
Construction was completed in 38-days (18% ahead of schedule)
Pipeline Design, Assessment & Rehab
This project was recognized by Engineering News Record in their Regional 2014 Best Projects for Texas | Louisiana competition (Small Project Category | Award of Merit).
This was the first construction contract completed as part of the $2+ billion Integrated Pipeline (IPL) program.