Any owner or occupant engaged in construction or demolition of any building or improvement upon or near the public ways and property shall protect all excavations or exposures of any kind by suitable barricades or guards by day and by warning lights at night. The failure, neglect, or refusal of the owner or occupant to erect and maintain such protections shall constitute a violation of this section, and the city may stop all work upon the buildings and improvements until suitable protections are erected and maintained in the required manner.