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CATEGORICAL EXCLUSION ACTION CLASSIFICATION FORM
TIP Project No. B-5407
W.B.S. No. 46122.1.1
Federal Project No. BRZ-1311(13)
A. Project Description:
The purpose of this project is to replace Polk County Bridge No. 34 on
SR 1311 (Rock Spring Road) over Walnut Creek (See Figure 1 and Figure 2 for
project vicinity and location). Bridge No. 34 is 102 feet long. The replacement
structure will be a bridge approximately 110 feet long providing a minimum 31
feet clear deck width. The bridge will include two 11-foot lanes and 4-foot
offsets. The bridge length is based on preliminary design information and is set by
hydraulic requirements. The roadway grade of the new structure will be no less
than 0.3% to facilitate deck drainage.
The approach roadway will extend approximately 200 feet from the east end of
the new bridge and 140 feet from the west end of the new bridge. The approaches
will be widened to include a 22-foot pavement width providing two 11-foot lanes
and 3-4 foot paved shoulder. The roadway will be designed as a Minor Collector
using 3R guidelines with a 60 mile per hour design speed (See Figure 3).
Traffic will be detoured off-site during construction including the use of SR 1310,
SR 1161, and SR 1311.
B. Purpose and Need:
NCDOT Bridge Management Unit records indicate Bridge No. 34 has a
sufficiency rating of 21.5 out of a possible 100 for a new structure.
The bridge is considered structurally deficient due to superstructure condition
appraisal of 5 out of 9 and a substructure condition appraisal of 3 out of 9
according to Federal Highway Administration (FHWA) standards. The bridge
also meets the criteria for functionally obsolete due to structural appraisal of 2 out
of 9 and a deck geometry appraisal of 4 out of 9.
The superstructure and substructure of Bridge No. 34 have timber elements that
are aging, and it has an estimated remaining life of four years. Timber
components have a typical life expectancy between 40 and 50 years due to the
natural deterioration rate of wood. Rehabilitation of a timber structure is generally
practical only when a few elements are damaged or prematurely deteriorated.
However, past a certain degree of deterioration, most timber elements become
impractical to maintain and upon eligibility are programmed for replacement.
Timber components of Bridge No. 34 are experiencing an increasing degree of
deterioration that can no longer be addressed by reasonable maintenance
activities, therefore the bridge is approaching the end of its useful life.