The disastrous Miami condo collapse is creating deep anxiety in south Florida, where buildings are prone to erosion by seawater. There’s a renewed push to check all buildings in the area for signs of danger. Robert Lisman, who lives just two buildings down from the tower that imploded, discovered a large, disturbing crack in a support column in his parking garage. So is your building safe? We spoke to structural engineer Greg Batista, who says many condos have troubling structural problems.