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Geotechnical Memorandum
A geotechnical report is not necessary for this project. Below is a summary of the bridge components that
interface with the soil and a description of how the design is not dependent on geotechnical investigation.
The existing bridge is founded on timber piles which will not be modified in a way that affects their
capacity to support the bridge (e.g. embedment depth or bearing capacity). In addition, loads to the piles
will be less than for the previous railroad use.
Existing soils behind the end bents of the bridge consist of granular material originally used to support a
railroad. Loads for the trail use are less than the original railroad loading and will not compromise the
approach soils.
Rotting timber end walls, which support the approach embankment, will be replaced in kind. The existing
timbers have been in place for many decades and the new timbers are expected to meet the design life of
the interim trail improvements. Temporary excavation slopes will not exceed the slope of existing stable
slopes at the sides of the approach embankment.
Rotting timber wing walls, which support the approach embankment, will be replaced with precast
concrete blocks. The concrete blocks will be more stable than the existing condition and will meet the
design life of the interim trail improvements.