A history buff who has enjoyed a 36-year career in construction, Charlie Gannon, a project manager for Walsh Construction, certainly appreciates the significance of having delivered the longest-ever bridge slide. Last April, his crews used strand jacks to pull a 2,428-ft-long, four-span truss 55 ft on refurbished piers, cutting downtime for motorists passing between the Ohio River towns of Milton, Ky., and Madison, Ind.