Jacksonville’s Main Street Bridge will be closed from 6:30 p.m. Friday, June 23 to Sunday, June 25 at 6 a.m. and again Monday, Tuesday, Thursday, and Friday nights (June 26, 27, 29, and 30) from 6:30 p.m. until 6 a.m. and Wednesday night, June 28 from 9 p.m. until 6 a.m. The closures are part of improvements to the mechanical, electrical and structural systems.