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SOIL-STRUCTURE INTERACTION ANALYSIS OF CULVERTS. CEE 434 GEOTECHNICAL DESIGN FALL 2008. Classes of Underground Conduits. Definitions. STRUCTURAL DESIGN. Marston Theory. Free Body Diagram for Ditch Conduit. Maximum Loads on Ditch Conduits. C d Coefficient for Ditch Conduits. BACKFILL.
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SOIL-STRUCTURE INTERACTION ANALYSIS OF CULVERTS CEE 434 GEOTECHNICAL DESIGN FALL 2008
BACKFILL • GRANULAR MATERIALS • COMPACTION: 100 % Proctor Density • CONTROLLED PLACEMENT & LIFTS • HAUNCH SUPPORT
The next series of slides were downloaded from the Geotechnical photo album site, maintained at UC Davis http://cee.engr.ucdavis.edu/faculty/boulanger/geo_photo_album/Underground%20structures/Long-span%20culverts/Culverts%20-%20main.html
BENEFITS OF CSP? • Long Lengths • Light Weight • Durable • Gasketed Joints • Manning’s “n”=0.012 – 0.027 • Proven Design Methodology • Minimum Covers to 12” • High Fill Heights • Cost Effective
Functional FAST Installation Durable High Load Capacity Cost Effective Pre-Engineered Shapes and Sizes Recognized Design Methodology and Fill Height Tables Easy to Use Hydraulic Nomographs STRUCTURAL PLATE
Large culvert structures like this one are shipped to the job site in pieces and bolted together at the site. They can be erected with light equipment and unskilled labor, but experienced supervision is essential.
This aluminum culvert structure is ready to be backfilled. It has aluminum end walls and wing walls to retain the fill. The vertical bins will stabilize the fill and reduce the earth loads on the wing walls.
Because long-span culverts depend on soil-structure interaction for stability, intimate contact between the invert and the underlying soil, and good compaction of the backfill alongside and over the top of the culvert, are essential. Here a layer of sand backfill is being spread prior to compaction. Because the structures are unable to withstand much eccentric loading, the backfill must be brought up equally on both sides of the structure.
Here three culverts, side-by-side, provide a bridge across a river. These are “arch culverts,” without metal inverts. The haunches of the metal arches are supported on concrete footings, and a concrete invert prevents erosion of the stream bed in periods of high flow in the river.
PROPER INSTALLATION • Quality Granular Structural Backfill • Placement in 6” – 8” lifts • Bring fill up in a balanced manner • Compaction: 100% Proctor Density • Protect ends from erosion • Maintain adequate minimum cover for highway and construction loads
This photo shows the largest culvert structure ever built – a 60-foot span structure in Newfane, New York. It collapsed in 1974, a few days after this photo was taken, after a few feet of fill was placed over the crown of the structure. Fortunately, the failure occurred during the noon hour, when no one was inside the culvert, and there were no deaths or injuries. The investigation of the failure lead to improved design methods.
This aluminum culvert, with straight aluminum end walls, serves as a bridge over a small stream.
The following series of slides are the courtesy of CON-SPAN Bridge Systems http://www.con-span.com/CON-SPAN/noflash.html
This photo shows the collapsed roof of a culvert structure. The collapse occurred when the contractor, working without supervision over a weekend, graded the fill over the top of the culvert so that it sloped from one side to the other. The culvert was unable to sustain the unsymmetrical load imposed by the sloping fill, and it collapsed. There were no deaths or injuries.
CON-SPAN and BEBO Bridges BEBO CON-SPAN
