YIELDING SEAM MULTI-PLATE PIPE
The 40-year old steel truss bridge spanning Rock Creek Canyon was destroyed during a brush fire in March 1977. This crossing was closed to traffic until October 1979 when a rock fill embankment which replaced the bridge was completed. Two 7-gage, 168 inch diameter multi-plate pipes were installed to carry Rock Creek through the fill. The pipes are of the "keyhole slotted" type supporting approximately 80 feet of fill and are 328 and 319 feet in length. The keyhole slot design allows for stress-relieving in the pipe as the embankment is placed by slippage of the longitudinal joints. As the load on the pipe increases, the connecting bolt slips into the undersized slot. The result is that higher fills can be supported than before for a given gage of pipe. If a conventional multi-plate had been used, a #1 gage rather than #7 gage would have been required. It is estimated that the contractor saved about 20 percent in material costs and 30 percent in erecting costs in comparison to a conventional multi-plate installation. Erecting costs were reduced by the greater flexibility and ease of handling of the 7 gage pieces. Also, the 7 gage alternate only required 4 bolts per foot of joint, whereas, the 1 gage would have required 8 bolts per foot. The overall savings was less than the materials and erection savings, due to patent right costs and slightly higher shop fabrication costs for the "keyhole slot" design. (Author)
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Corporate Authors:
Idaho Transportation Department
3311 W State Street, P. O. Box 7129
Boise, ID United States 83707-1129 -
Authors:
- Merritt, W E
- HILL, J W
- Publication Date: 1984-11
Media Info
- Features: Photos;
- Pagination: v.p.
Subject/Index Terms
- TRT Terms: Construction; Costs; Design; Fills; Longitudinal joints; Pipe culverts; Stress relieving
- Uncontrolled Terms: Construction costs
- Subject Areas: Construction; Design; Finance; Geotechnology; Highways; Hydraulics and Hydrology; Materials; I26: Water Run-off - Freeze-thaw;
Filing Info
- Accession Number: 00391650
- Record Type: Publication
- Report/Paper Numbers: Exp. Pro. 78-01-2 Final Rpt., ER-2721(1)
- Files: TRIS, STATEDOT
- Created Date: Jan 30 1985 12:00AM