The bond required by section 9-2-2 of this chapter shall be in the sum of twenty thousand dollars ($20,000.00) and shall be executed by a surety company authorized to do business in the state, conditioned to save the city harmless from any damage or injury whatsoever to any person or property of any description, however owned, by reason of leaving open any excavation or tunnel or by reason of failure to properly guard any such excavation or tunnel or failure to place red lights at such excavation or tunnel at night. Any person may furnish a yearly bond conditioned as hereinabove set forth. (1975 Code § 12.16.030)