Metro says it has no cause yet for the failure of a retaining wall section on the 405 freeway improvement project in Sepulveda Pass, but is aware of it.
A MSE (Mechanically Supported Engineering) retaining wall, located along the southbound I-405 at Mountain Gate, suffered a localized failure on Thursday, December 1. The failure occurred on Caltrans right-of-way, west of the freeway, in our construction zone. No one was injured and our geotechnical team deemed the freeway and Sepulveda safe for the traveling public. Traffic has not been restricted at this location.
The wall, approximately 2,000 feet long, is part of the work to relocate the Skirball Center Dr on-ramps south of their present location on the Skirball bridge. The portion of the wall that has been compromised is only 20 feet long. The project has been aware of deficiencies in this portion of the wall for a few weeks and were preparing a partial deconstruction plan when the panels failed. The wall has been stabilized and there is no danger to the traveling public. The contractor is currently performing an in-depth investigation to the cause of the localized failure. Experts have been brought in to collect forensic evidence. We cannot speculate at this time as to what caused the failure. Once a thorough and complete investigation has been finalized and approved by Metro and Caltrans, the contractor will create a mitigation plan.
Until the investigation is complete, work on the other MSE walls along the project has been halted. Our path forward will be determined by the outcome of the investigation.