University Hall, located in Charlottesville, Virginia, is the home of the University of Virginia men and women's basketball teams. With a seating capacity of over 9,000, it serves as a key sports and entertainment facility for the region. The building, similar, but smaller in structure to the Houston Astrodome, is covered by an 87-meter diameter concrete dome. The dome consists of 32 precast segments with a cast-in-place thrust ring that was originally prestressed by being wrapped with smooth wire encased in concrete. During a structural inspection in the fall of 1998, it was discovered that the prestressing steel strands in the ring beam had experienced pitting corrosion, and that some wire and strand breakage had occurred. A temporary repair was performed using external monostrand tendons, which aesthetically detracted from the visual appearance of the building.
A structural engineering firm, retained by the University to design a permanent repair solution, developed an innovative repair design in which the structural strengthening of the dome would be aesthetically unobtrusive. This design was approved by the University, and the project went out for public bid. While reviewing the bid specifications, a concrete repair contractor working with a post-tensioning engineer saw the opportunity for a refinement of the repair design that would be structurally efficient, physically smaller, cost effective and would provide an aesthetically pleasing solution. This proposed refinement was subsequently reviewed and approved by the University.
The strengthening of the University Hall ring beam utilized a unique application of post-tensioning to provide a structurally elegant and aesthetically pleasing result. Working closely as an efficient team, the repair contractor, post-tensioning specialist, engineer and owner devised an efficient and unobtrusive structural strengthening solution that could be accomplished during an extremely short time frame, while allowing complete access to the facility during construction operations. The project was completed on time and under budget and provides an excellent template for the collaborative development of unique solutions for challenging projects.