It shall be unlawful to maintain sidewalks in a dangerous condition in front of, adjacent to or upon any premises. Whenever the owner or occupant of any premises in the city is notified that the sidewalk in front of, adjacent to or upon said premises is dangerous by the engineering department, it shall be the duty of such owner or occupant to raise, lower or replace said sidewalk as specified by said engineering department so as to end said dangerous condition in the time prescribed by said department. (1988 Code §24.502)