The Varella Avenue project is a 0.6 miles (1 km) sidewalk connecting
the SR 16 sidewalk system with the St. Augustine High School
in St. Johns County. Varella Avenue is a two-lane rural paved
roadway with roadside swales through an older residential area.
| An innovative approach
was used incorporating sidewalk flumes and Type ‘D’ curbing
to meet clear zone requirements. |
The sidewalk was constructed along
the west side of the roadway within a limited right-of-way envelope.
The space available to construct the sidewalk and reconstruct
the drainage swale varied from 11.5 feet (3.5 meters) to 20
feet (6.1 meters). The construction of a 5 foot (1.5 meter)
sidewalk in this envelope did not allow much room to construct
a swale with side slopes that met the required clear zone requirements.
Sidewalk Flume Detail |
Since the swale
ditch reconstruction would create side slopes steeper
than permitted in the clear zone for a rural section and
reconstruction of the roadway was not an option an innovative
approach was developed for the project. A Type ‘D’ curb
was “fitted” to the edge of the roadway and “sidewalk
flumes” were constructed at low points along the roadway
to transmit stormwater runoff to the adjacent swales.
These flume construction costs were approximately $150
per location and the Type “D” curbing costs were $10/foot.
This inexpensive construction technique allowed the sidewalk
and drainage swale to be constructed in a very limited
space and still meet the required design criteria and
provide an adequate drainage system for the road. |
Sidewalk flumes can be
easily incorporated into any rural roadway section and
do not require any roadway reconstruction.
Curb side view of sidewalk flume.
Behind the sidewalk view for typical sidewalk flume installation.
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The sidewalk flumes were very simple to construct. A 3 feet
(0.9 meter) by 6 feet (1.8 meter) slab was constructed to bridge
the flume and provide continuity to the sidewalk. The construction
of a typical flume installation is shown in the following photographs:
The sidewalk was constructed
with minimal disturbance to adjacent properties.
Varella Avenue prior to sidewalk
construction.
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