Calaveras Road Landslide Repair

The City of Milpitas (“City”) is seeking proposals from qualified proposers (“Proposer”) in response to this Request for Proposals (“RFP”) to perform assessment, design, construction support, permitting, and environmental analysis for the landslide repair and improvement of the City owned road segment on Calaveras Road approximately 1,500 feet east of the Evans/Piedmont Road and Calaveras Road intersection. The Project site is located approximately 1,500 feet east of the Evans/Piedmont Road and Calaveras Road intersection.

Over the past three decades, this roadway segment has sustained repeated damage from adjacent slope failures. The following is a summary of the City’s improvement efforts undertaken in response to these events.

• 1992: Installation of three Mechanically Stabilized Earth (MSE) retaining walls (Retaining Wall No. 1, 2, and 3) and reconstruction of the roadway.
• 2002: Installation of a grade beam wall at Retaining Wall No. 3, reconstruction of the roadway and storm drain improvements.
• 2017: Installation of pin-pile wall at Retaining Wall No. 3 with a subdrain system and reconstruction of the roadway.

On December 31, 2022, a severe rainstorm triggered renewed ground movement on the southern side of Calaveras Road, in the proximity of previously installed pin-pile wall at Retaining Wall No. 3, located approximately 1,800 feet east of the Evans/Piedmont Road intersection. The storm caused a shallow slope failure, exposing the upper five feet for approximate 100 feet of the 200-foot-long wall. Additionally, vertical cracking parallel with the existing wall suggests the extent of the slope failure includes the roadway section.