A. Each coal room or other opening under a sidewalk shall be constructed as follows: The outer wall next to the street shall be formed of concrete, stone or brick not less than twelve inches (12") in thickness, or such additional thickness as the city engineer may require, and no part thereof shall project beyond the curbstone. The sides or return walls shall be of the same materials and at least eight inches (8") thick. The top shall conform with the sidewalk grade and shall be constructed of reinforced concrete of a thickness and design approved by the city engineer, and supported on iron beams or reinforced concrete beams of sufficient strength to carry a load of one hundred fifty (150) pounds to the square foot, exclusive of the weight of materials used in construction.
B. Where an excavation has been made under a sidewalk, any opening in the sidewalk shall be of a size and design approved by the city engineer, and shall be covered with an iron manhole and cover not exceeding twenty four inches (24") in diameter, or by sidewalk doors of steel or iron, set flush with the surface of the walk. No cover for any such opening shall have a surface that may, under any conditions, become slippery or hazardous to pedestrians.
C. Every opening in a sidewalk, leading to an underground room or space, shall at all times be maintained in good condition. No such opening shall be allowed to remain open, except with the proper barricade, and at no time longer than absolutely necessary. Any person in charge of such underground space and opening, shall be liable for any and all damages resulting from accident or injury caused in any way by such opening. (1960 Compilation § 14-109)