HALL regraded the outfall ditch and installed a sump and pump for continual drainage to overcome higher elevation downstream in creek bed, outside of project limits. Removed 2,300′ of existing paved invert in 96″CMP and relined 2,300′
of parallel existing 96″ CMP with 78″ Contech Aluminized two piece structural plate, and 1,000′ of existing parallel 90″RCP with 84″ six piece tunnel liner plate. Grouted annular space of all new liners with lightweight cellular grout, being pumped as far as 1,800′ through 2″ hoses and piping, to reach the injection points.
Access to the work was very limited as we had to carry in the 78″ twp piece structural plate liner as far as 4,300′ to reach the upstream end, where the new liner began, under Concourse D, and assembled it inside the existing storm drain, which carried all of the airport’s surface water runoff of some 1,000 acres. One tenth of an inch or rain increased the depth of flow inside the pipes by 3 vertical feet, making work inside, impossible.