Utility Tunnel Repair

Utility tunnels are frequently used in major government, university, medical, etc. campuses. These network of concrete tunnels can be very long and have cross sections of typically 7 ft x 7 ft (2m x 2m). Utility tunnels house various water, hot water, pressurized air, gas, etc. pipelines and communication and fiber optics cables. These tunnels are subject to water penetration from ground and the lack of ventilation leads to a hot and humid environment that is a fertile ground for corrosion of the reinforcing steel. Access to these utility tunnels is through a few access ports or manholes that can be several hundred feet apart. The pipes hanging on the walls leave little access to the walls and ceiling. Conventional repairs using steel and concrete in such tight environment is very costly and time consuming.

Carbon or glass FRP fabric offers a great solution to repair and strengthen these utility tunnels. The damaged concrete is removed and if necessary the concrete surface is patched using gunite. FRP fabric can be saturated with resin outside the access port and passed through to the crew inside the tunnel that will apply the fabric to the walls and ceiling of the utility tunnel. QuakeWrap engineers will develop designs based on the original capacity of the tunnel, the level of corrosion and any additional loads that may be imposed on the utility tunnel in the future. These sealed deign calculations and drawings will be provided to the client.

Features & Benefits

Advantages of repair of utility tunnels with FRP include:

  • All repairs are trenchless, requiring zero excavation
  • Walls and ceiling can be strengthened above original limits
  • Flexible FRP fabric makes installation inn tight spaces possible
  • Minimal increase in wall thickness (typically ¼ inch (5mm))


PROJECT PAPER: Corrugated City of Steam – Emergency Repair of the Drama Tunnel (PDF)

PROJECTS RESOURCE: More papers on structural repair and renewal projects here at QuakeWrap University