An excavator shall not interfere with any existing utility without the written consent of the city council and without advance notice to the owner of the utility. If it becomes necessary to relocate an existing utility, it shall be done by the utility owner unless the owner otherwise directs. No utility, whether owned by the city or by a private enterprise, shall be moved to accommodate the permittee unless the cost of such work be borne by the permittee or an expressly written agreement is made whereby the utility owner and the excavator make other arrangements relating to such cost. The permittee shall support and protect by timbers or otherwise all pipes, conduits, poles, wires or other apparatus which may be in any way affected by the excavation work, and shall do everything necessary to support, sustain and protect them under, over, along or across the work. In case any of the pipes, conduits, poles, wires or apparatus should be damaged (and for this purpose pipe coating or other encasement or devices are to be considered as part of a substructure), they shall be repaired by the agency or person owning them, but the utility owner shall be reimbursed for the expense of such repairs by the permittee. It is the intent of this chapter that the permittee shall assume all liability for damage to substructures, and any resulting damage or injury to anyone because of such substructure damage and such assumption of liability shall be deemed a contractual obligation which the permittee accepts upon acceptance of an excavation permit. The city need not be made a party to any action because of this chapter. The permittee shall inform itself as to the existence and location of all underground utilities and protect the same against damage. (1978 Code § 11-392)