General Model Study of Scour at Proposed Pier Extensions - Santa Ana River at BNSF Bridge, Corona, California

A proposed pier nose extension intended to reduce the local pier scour at the Burlington Northern Santa Fe Railway crossing on the Santa Ana River near Corona, CA, was tested in a general physical model. The applied model was a 1:30 Froude-scaled model of the bridge piers, other related structures, and the adjacent channel. Data from the model provided a qualitative and quantitative evaluation of the local scour behavior at the estimated worst-case scenarios for both the existing and proposed conditions. The existing conditions represent the current prototype configuration exposed to potentially larger future dam releases from the upstream Prado Dam. The proposed condition includes pier nose extensions, concrete caps (pile enclosures), and flow guide walls, all intended to reduce scour at the bridge. The primary location for the minimum scour elevation (maximum scour depth) occurred around pier set 5. The proposed conditions showed as high as 60 improvement in reducing the scour depth with the proposed conditions configuration.