It shall be unlawful for a person to erect or maintain any awning over any sidewalk unless all parts of the awning are elevated at least seven feet above the surface of the street or sidewalk and the roof or covering is made of duck, canvas or other suitable material supported by iron frames or brackets securely fastened to the building, without any posts or other device that will obstruct the sidewalk or hinder or interfere with the free passage of pedestrians. [Ord. 409 § 3, 1989; Code 1975 § 8-2.10.]