Gilman Drive Storm Drain Emergency Replacement
Orion Construction delivered an emergency design-build replacement of a failed 132-inch storm drain under Gilman Drive, stabilizing nearby residential buildings and restoring one of La Jolla’s primary storm conveyance lines.
Owner: City of San Diego
Location: Jolla Drive
Designer: Harris and Associates
Contractor: Orion Construction Corporation
Delivery Model: Design-Build
Contract Value: $10.7 million
Schedule: 2023 - 2024
Scope: A 132” CMP storm drain failed, causing a sinkhole adjacent to a multi-family residential building. The team immediately mobilized to stabilize the soil and diminish the settlement of the residential structures. It was imperative that the shoring and repairs be implemented as expeditiously as possible to accommodate the ongoing wet season. The team used a design-build approach, with engineering staying just ahead of ongoing construction to expedite repairs and mitigate property loss and additional damage to the stormwater system.
Challenges: The emergency response to this project was critical, as people's homes were at risk of collapse. The CMP pipe is 40’+ deep, old (1960s), and failing from corrosion and structural degradation. Additional constraints included inconsistent soil conditions, which required multiple ground injections to maintain stability around the excavation. Work occurred during two of the largest rain systems that have hit the Southern California coastline in decades. The crews had to work around multiple rain events and establish temporary measures to keep water flowing while the work continued. The deep excavations required significant shoring systems, including beam-and-lag systems.
Results: The newly replaced 132” diameter CMP stormwater pipe section will also be lined with a cementitious/polymer material to increase the life span and provide a non-corrosive surface for the water to travel. The Design-Build Team provided expedited emergency repair services with a focus on public safety, protection of the built environment, and sustainment of the City’s stormwater infrastructure. This project provided immediate repairs and a path forward for the City to proactively address additional repairs to avoid future line failures.
