摘要: |
Ten of the corrugated steel pipes under U.S. 12 near Helena were in poor structural condition with deteriorated inverts and badly in need of replacement. Sand and debris were accumulating in these culverts, reducing their capacities and requiring constant care by maintenance forces. The poor condition of the culverts prompted MDT to take immediate mitigating measures. MDT had two options to address the problem. Option 1 was to excavate and replace the culverts, which would have required lane closures that interfered with traffic flow. Option 2 was to reline the culverts using trenchless technologies without impeding traffic flow. After exploring the two alternatives and evaluating project and user costs, MDT selected the trenchless technologies to rehabilitate the culverts under U.S. 12. |