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The ongoing California Department of General Services (DGS) Resources Building Renovation (RBR) Project is an ongoing seismic retrofit and modernization of the 17-story and 657,000 GSF structure located at 1416 Ninth Street, Sacramento, utilizing the Progressive Design-Build project delivery method. Long identified as one of the most seismically-vulnerable buildings in the State of California portfolio, the unique structural system, from the corrugated steel step-taper pile foundation to the truss moment frame superstructure, made seismic retrofit a technically challenging and costly effort, leading to numerous project deferrals. In early 2020, Thornton Tomasetti (TT) began working with DGS to study the building’s seismic vulnerabilities, align on goals for performance, develop a feasible concept retrofit utilizing supplemental viscous damping, and publish design criteria for the project to allow DGS selection of a design-builder. Once the Turner/AC Martin/HGA-led Progressive Design-Build team was engaged TT remained engaged as a Peer Reviewer for the final structural design package developed by Buehler Engineering. The project is slated for completion in late 2025. In this presentation, we will use the RBR as a case study to explore: Progressive design build as a project delivery method; The seismic vulnerabilities presented by the RBR, including the novel truss moment frame superstructure; Pros and cons of supplemental viscous dampers and their selection as part of the retrofit strategy; The project criteria development process and the challenge of creating acceptance criteria for a novel structural system; Keys to successful project peer review.