Subsurface excavation adjacent to any building for the purpose of lighting, ventilation or storage under any sidewalk within the city shall not be constructed, repaired or altered without first having secured a permit from the city to perform such work pursuant to section 9-5-2 of this title. All such excavations shall be engineered to specifications approved by the city engineer or a designated agent of the city council in such manner as to support a live load of not less than two hundred (200) pounds per square foot of surface or area of such sidewalk; and all opening in sidewalks into any excavations under the same shall be covered by a grating or trapdoor which will support a like load and the same shall, at all times, be securely closed when not in use and shall be properly and securely guarded when open; and under no circumstances shall such trapdoor or grating let floodwaters from the street or sidewalk enter nor shall they constitute an obstruction to foot traffic; and any such trapdoors or gratings installed shall have an approved finish that will form a grip for the feet of pedestrians. (Ord. 391, 10-2-2012)