The Chicago Housing Authority’s board approved a plan Tuesday that would allow the agency to demolish 1,800 units. Three public housing developments are at the center of the demolition plan and resident protest: Altgeld Gardens, Lathrop Homes and Cabrini Rowhouses. CHA officials are sending its plan to Housing and Urban Development officials later this week. Under the board-approved plan, more than 600 units at Altgeld Gardens would be demolished. The sprawling development on the city’s southern edge has been a challenge to redevelop, with its geographic isolation often cited as a principal reason. CHA has assessed that the Cabrini rowhouses should not be 100 percent public housing. Those apartments are within the mixed-income housing footprint at Cabrini. Finally, Lathrop Homes on the North Side caused friction between residents and CHA. Residents want the housing to remain for low-income, working families. CHA has indicated it is committed to completing a community engagement process at each site prior to demolition.