I often ride up the sidewalk on Joncaire. There are sometimes pedestrians coming from Pitt to the parking lot, but not often. The stairs from Joncaire up to the Frick building have a bike channel, but it's a long steep haul.
Riazzi Substation project now requires full closure of Boundary Street between Joncaire & Filmore St. from Monday, January 11 through March 31 after unexpected subsurface obstructions were discovered in the roadway which now requires much more extensive excavation workThere's no mention of an MPT in this announcement, but they'll probably have to post a detour. We can hope it includes bikes and pedestrians. The notice doesn't mention a closure of Joncaire. So I suppose the detour for Junction Hollow Trail to Oakland, CMU, etc would be Joncaire > Bouquet > Clemente Dr > Schenley Plaza. Joncaire is a Belgian block (aka cobblestone) street, so that's no fun. However, there are no structures on the north side of the street, so I suppose it doesn't meet the definition of business district, so the business district prohibition of bikes on sidewalks probably doesn't apply. Of course, I'm not telling you to ride your bike on the sidewalk, just sayin'