Update for March 21, 2008
The retaining wall redesign effort is nearing completion. The redesign was undertaken so the road can be opened to traffic on a daily basis during wall construction. (The original contract included mechanically-stabilized earth walls which required weekly road closures to construct.)
Two types of retaining walls will be constructed – cast-in-place concrete cantilever walls and cast-in-place concrete walls with micropile and rock anchors. Both types are constructed using reinforced concrete. The cantilever wall looks like an upside down T, and the vertical stem and horizontal footing act as a unit to retain soil behind the wall. The cantilever wall is less expensive than the micropile/rock anchor type, but its use is limited to areas where there is ample width for the footing. The cast-in-place wall with micropile and rock anchors is essentially a vertical wall that is tied into the existing backslope with rock anchors and connected to the underlying ground with micropile. Rock anchors and micropile are constructed by drilling and grouting steel bars into the ground.
Part of the design process is to verify the assumptions we used are indicative of the actual site conditions. To do this, Debco Construction installed four rock anchors and four micropile on Wednesday, March 19. Next week, the micropile and rock anchors will be tested and that data will be used to validate or revise our design assumptions.
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Micropile Installation |
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Rock Anchor Installation |
Safe travels this weekend,
Jane Traffalis
Construction Project Manager
Western Federal Lands Highway Division
Federal Highway Administration
If you would like to provide a comment, click here: salmonriver@mail.wfl.fhwa.dot.gov