921.06 WORK REQUIREMENTS.
   (a)   The work of the company shall be first class in every respect. The City shall have the right to insist that all work be performed by competent foremen and workmen and may require that any company employees doing unsatisfactory work be removed. All structures shall be constructed in a workmanlike manner, true to line, grade and dimensions, and of ample strength to withstand all anticipated loads and stresses. The City may require that unsatisfactory structures be rebuilt. Materials shall be entirely suitable for the structures contemplated; they shall be so delivered and stored as to give least inconvenience to the public and shall be used within a reasonable time after delivery.
   (b)   Excavation for structures shall be so conducted as to keep interference with other uses of streets and public grounds to a minimum and shall be subject to City control as to location and extent. Suitable bridges over trenches at street intersections and at other locations where they are deemed necessary shall be required by the City. Excavation in general shall be open trench and tunnelling will be permitted only in specific locations approved by the City. Structures of the City and other companies encountered during work shall be called to the attention of the City promptly and all necessary precautions taken to protect them. No such structures shall be disturbed until the authorization of the owner is secured. The City may require such bracing, sheeting, footing and other measures as are deemed necessary to protect structures.
   (c)   Backfilling of excavations shall be done by the company under the direction of the Director of Service and shall follow the completion of work as closely as possible. The backfilling shall be made with sand well puddled and tamped, and material taken from the trench shall be removed and not used for backfilling.
   (d)   Temporary paving of brick shall be constructed by the company on backfills within the paved portion of any street, and such temporary pavement shall be maintained by the City, such construction and maintenance to be at the contractor's expense. When, in the opinion of the Director of Service, the backfill has fully settled, the temporary paving shall be removed and permanent repairs made by the City at the company's expense. If the deposits above mentioned are insufficient to cover the costs, the balance shall be collected from the company. If more has been deposited than is needed, the balance shall be refunded to the company.
   (e)   Curbing, walks, drives and other City structures removed or disturbed during work shall be replaced by the City at the expense of the company unless otherwise provided at the time the permit is granted. If the company is permitted to do any part of such replacement work it must be done under City inspection. Pavement base shall be of at least two inches greater thickness and two inches wider than the base removed. Concrete shall have adequate steel reinforcement to the satisfaction of the City. Pavement surface shall be of the same type as the surface removed except by written permission of the City. In general, replaced structures shall be of greater thickness, strength and durability than the original structures to compensate for possible subsurface settlements, or failures, for difficulty in bonding old and new work, and for structural weakening due to loss of homogeneity.
   (f)   Wooden poles carrying wires or cables shall be of one piece and shall not be extended in length or height by splicing, bolting or otherwise fastening thereto any other piece of wood or metal.
   (g)   In an emergency the City may enter upon any work and execute such measures as may be necessary to prevent loss of life or serious damage to property or persons. Any costs arising out of such emergency work will in general be borne by the company.