A proposed 84-in. steel water line intersects the active normal dip-slip Woodgate Fault, of which the estimated vertical movement rate is approximately half inch per year with a down-to-the-coast dip angle of 77°. This surface water transmission main is owned by the North Harris County Regional Water Authority (NHCRWA) which comprises 335 square miles and includes approximately 710,000 residents. The anticipated vertical and horizontal movements within the design lifespan pose a significant risk to the water line since local buckling may occur due to excessive ground movement. Other challenges, such as (1) constraint of right of way (ROW), (2) balancing cost and reliability, and (3) accessibility for operation and maintenance (O&M), further complicate the design. To meet all design requirements, multiple design alternatives were evaluated, and an optimized “design and maintain” approach was selected. The design concept is verified and refined by finite element analysis (FEA) using a nonlinear Winkler-based soil spring model. It is found that the proposed O&M guidelines can reduce the risk of the water line by limiting the compressive strain induced in the steel carrier pipe, hence preventing local buckling. Also, the proposed approach reduces the overall construction cost while maintaining an acceptable level of reliability, and the O&M is facilitated by providing maximum accessibility to the couplings.

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A proposed 84-in. steel water line intersects the active normal dip-slip Woodgate Fault, of which the estimated vertical movement rate is approximately half inch per year with a down-to-the-coast dip angle of 77°. This surface water transmission main is owned by the North Harris County Regional Water Authority (NHCRWA) which comprises 335 square miles and includes approximately 710,000 residents. The anticipated vertical and horizontal movements within the design lifespan pose a significant risk to the water line since local buckling may occur due to excessive ground movement. Other challenges, such as (1) constraint of right of way (ROW), (2) balancing cost and reliability, and (3) accessibility for operation and maintenance (O&M), further complicate the design. To meet all design requirements, multiple design alternatives were evaluated, and an optimized “design and maintain” approach was selected. The design concept is verified and refined by finite element analysis (FEA) using a nonlinear Winkler-based soil spring model. It is found that the proposed O&M guidelines can reduce the risk of the water line by limiting the compressive strain induced in the steel carrier pipe, hence preventing local buckling. Also, the proposed approach reduces the overall construction cost while maintaining an acceptable level of reliability, and the O&M is facilitated by providing maximum accessibility to the couplings.

**[Access the Conference Proceedings Paper on ASCE Library](https://ascelibrary.org/doi/10.1061/9780784483619.014)** 


Design of a Large Diameter Water Line at Active Fault Crossing

Papers from sessions of Pipelines 2021, held virtually August 3–6, 2021. Sponsored by the Utility Engineering and Surveying Institute of ASCE. The conference provides a forum for pipeline engineers and practitioners from all around the world to share their experiences in meeting the challenges of today's pipeline infrastructure. This premier industry event has become the conference of choice for utility and pipeline owners, design and consulting engineers, contractors, manufacturers, suppliers, students, educators, researchers, and pipeline professionals. The conference includes surveying as it relates to pipeline and utility projects. This event will provide a dynamic and inspiring venue for participants to share and gain valuable knowledge related to planning, designing, constructing, renewing, operating, managing and maintaining the pipeline assets.

[Paper Proceedings](https://doi.org/10.1061/9780784483602)

Conference DOI: https://doi.org/10.26226/m.6454f875c8d4320012b71046