Sidewalks are the responsibility of the property owner. This includes snow removal and replacement.
PM-303.3 Sidewalks and driveways: All sidewalks, walkways, stairs, driveways, parking spaces and similar areas shall be kept in a proper state of repair, and maintained free from hazardous conditions. Stairs shall comply with the requirements of sections PM-304.10 and PM-702.9
Below you can reference the full Code of Ordinances and Property Maintenance Code.