Kleinfelder is a prime consultant on the City of Los Angeles’ First Street Viaduct Retrofit and Rehabilitation project—a historic structure located near downtown Los Angeles. The project involves seismic retrofit of the viaduct’s substructure elements, widening of the bridge deck and reconfiguration of the roadway to accommodate safer traffic flow, and re-grading and paving of the viaduct’s west approach to correct an existing dip.
Caltrans has given this bridge a Sufficiency Rating of 59.5, and it is classified as functionally obsolete primarily due to the insufficient deck geometry. The purpose of the project is to correct existing geometrical deficiencies, address seismic vulnerabilities, and preserve historic status. The historic structure must be preserved in accordance with Section 106 guidelines.
Kleinfelder thoroughly reviewed the Seismic Retrofit Strategy Report, Foundation Report, Draft Preliminary Environmental Study, and all other documents related to the bridge historic status. In order to minimize the impact to this structure, Kleinfelder utilized a limited bridge widening alternative and carbon fiber wraps for the columns. These solutions resulted in minimal change to the visual character of the bridge and allowed for a NEPA Categorical Exclusion to expedite the project approval.
The seismic retrofit and rehabilitation scope and details were developed to minimize the potential impact to this historic structure, with full review and approval through State Historical Preservation Office. This project is funded through the Federal Highway Bridge Replacement and Rehabilitation Program and Proposition 1B and is subject to review by Caltrans District 7 and Structures Local Assistance.