Utility Structures

Interstate Highways
. Where it would be more economical to carry utility lines across a freeway in a tunnel or on a bridge rather than in separately trenched and encased crossings,
refer to TxDOT’s Utility Accommodation Rules and
 provide a separate structure for the utility crossing. Such a structure may serve a joint purpose as a utility and pedestrian facility and/or sign support. In providing a utility tunnel or bridge, the following conditions
shall
 be met:
  • Isolate mutually hazardous utilities, such as fuels and electric energy, by compartmentalizing or by auxiliary encasement of incompatible carriers.
  • Conform the utility tunnel or utility bridge structure design, appearance, location, bury, earthwork, and markings to the culvert and bridge practices of the department.
  • Where a pipeline on or in a utility structure is encased, the casing must be effectively opened or vented at each end to prevent possible build-up of pressure and to detect leakage of gases or fluids.
  • Take additional protective measures where a casing is not provided for a pipeline on or in a utility structure, such as employing a higher factor of safety in the design, construction, and testing of the pipeline, than would normally be required for cased construction.
  • Communication and electric power lines must be suitably insulated, grounded, and preferably carried to a manhole located beyond the backwall of the structure. Insulate carrier and casing pipe from electric power line attachments.
  • Install shut-off valves, preferably automatic, in lines at or near ends of utility structures unless segments of the lines can be insulated by other sectionalizing devices within a reasonable distance.
  • Each Utility carried on the structure shall have an agreement with the State.
    Utility companies must agree that any maintenance, servicing, or repair of the utility lines will be their responsibility
Non-interstate Highways
. If utility lines have their own easement and it would be more economical to the department, adjust the lines across a highway by use of a utility tunnel or bridge. Where the utility lines are on a public right-of-way by sufferance and the adjustment of the utility is the sole responsibility of the private or public utility company, the department may permit the provision of a utility structure without cost to the department provided the same conditions outlined for Interstate Highways and all other pertinent requirements are met. If a structure is to serve as a joint utility-pedestrian crossing or a joint utility-sign support structure, the department will participate to the extent necessary for accommodation of pedestrians and highway signs only.