(A) Dimensions and materials. Casing pipes crossing under roadways shall be located at suitable approved alignments in order to eliminate possible conflict with existing or future utilities and structures, with a minimum 36 inches depth of cover between the top of the casing pipe and surface of the roadway where practicable. Casings shall be new prime steel pipe conforming to the requirements of ASTM Designation A-139. The minimum casing pipe size and wall thickness shall be shown in the following table for the water carrier pipe size indicated.
Carrier Pipe (Nominal) Size-Inches | Casing Pipe Outside Diameter-Inches | Casing Pipe Wall Thickness-Inches |
Carrier Pipe (Nominal) Size-Inches | Casing Pipe Outside Diameter-Inches | Casing Pipe Wall Thickness-Inches |
4 | 12
| 0.250 |
6 | 14 | 0.250 |
8 | 16 | 0.250 |
10 | 18 | 0.250 |
12 | 20 | 0.250 |
14 | 22 | 0.250 |
16 | 24 | 0.250 |
18 | 28 | 0.312 |
20 | 30 | 0.312 |
24 | 34 | 0.375 |
(B) Areas not under jurisdiction. For casing pipe crossings under roadways, railroads, or other installations not within the jurisdiction of the city, the contractor shall comply with the regulations of said authority in regard to design, specifications, and construction.
(C) Workmanship.
(1) The boring and jacking operations shall be done simultaneously with continuous installation, until the casing pipe is in final position. Correct line and grade shall be carefully maintained. Add-on sections of casing pipe shall be full-ring welded to the preceding length, developing watertight total pipe strength joints. The casing installation shall produce no upheaval, settlement, cracking, movement or distortion of the existing roadbed or other facilities. Following placement of the carrier pipe within the steel casing, masonry plugs are to be installed at each open end.
(2) Casing pipe holes shall be mechanically bored through the soil by a cutting head on a continuous auger mounted inside the pipe. The auger shall extend a minimum distance beyond the end of the pipe casing to preclude formation of voids outside of the pipe shell.
(3) The casing pipe shall be adequately protected to prevent crushing or other damage under jacking pressures.
(4) Required boring and jacking pits or shafts shall be excavated and maintained to the minimum dimension. Said excavations shall be adequately barricaded, sheeted, braced, and dewatered as required.
(Ord. 348, passed 12-3-87) Penalty, see § 77