City officials say they will seek federal help for a more long-term solution to the troubled Dorset Avenue bridge, including one that could involve remapping the path of the Intracoastal Waterway and building a taller, fixed-span bridge that’s 100 years old.In a statement on their Facebook page Thursday, the city’s mayor and commissioners underscored the importance of the bridge, which connects Ventnor Heights to the rest of Absecon Island and supports “residents, businesses, emergency services and visitors.”