About the Project
The Napa Valley Transit Authority embarked on an ambitious project to install a photovoltaic (PV) canopy structure at their site located at 101 Sheehy Court, Napa, CA. This project aimed to provide a sustainable energy solution while enhancing the functionality of the transit facility. The PV canopy is classified as a long-span array supported by wide flange (WF) sections for beams and columns. The PV modules are mounted on cold-formed steel purlins, which span between the beams, forming the primary structural framework.
In addition to its sustainable benefits, the project also aimed to showcase the technological advancements in structural engineering and renewable energy integration. By installing the PV canopy, the Napa Valley Transit Authority not only contributes to reducing carbon emissions but also sets a precedent for other transit authorities to adopt similar eco-friendly initiatives.
The design for the canopy was provided by KPFF Consulting Engineers.
Engineering Challenges
The project presented several engineering challenges, including the design and analysis of the long-span canopy structure. The lateral force-resisting system had to be meticulously planned, with the east-west direction using a steel ordinary moment frame and the north-south direction utilizing steel ordinary cantilevered columns, as per ASCE 7 Chapter 12. The columns were embedded into concrete pile foundations, adding another layer of complexity.
The design process involved addressing the potential for significant wind and seismic forces, given the location's seismic activity. Ensuring that the PV canopy could withstand these forces without compromising structural integrity was a key consideration. Moreover, the unique behavior of the connections, especially the two-way prying action on the pass-over plates, required precise analysis and validation, which could not be achieved through traditional hand calculations.
