HomeMy WebLinkAbout2011 03 28 Informational 106 Providing Information Regarding Charter School Guard RailCOMMISSION AGENDA
CONSENT
INFORMATIONAL X
ITEM 106
PUBLIC HEARING
REGULAR
MGR /DEPT
March 28, 2011
Meeting
Authorization
REQUEST: Public Works Department providing information to the City Commission
regarding a possible guardrail along S.R. 434 westbound adjacent to the
Choices-in-Learning Charter School wet detention pond.
SYNOPSIS:
A wet detention pond is currently being constructed adjacent to S.R. 434 as part
of the Choices-in-Learning Charter School project. A concern has been raised
about the possible need to have a guardrail installed along S.R. 434 to reduce the
potential for vehicles traveling on S.R. 434 westbound from driving into the pond.
CONSIDERATIONS:
Final Engineering for the Choices-in-Learning Charter School was approved by the City
Commission at the January 24, 2011 City Commission meeting. The project is currently
under construction, including a new wet detention pond located at the western end of the
site.
The wet detention pond is located adjacent to S.R. 434 westbound along a curve in front
of the Charter School and Central Winds Park (see Figure 1). At the March 14, 2011
City Commission meeting, the Commission raised a concern about the possible need to
have a guardrail installed along S.R. 434 to reduce the potential for vehicles traveling on
S.R. 434 westbound from driving into the pond.
The wet detention pond has a normal water elevation of 28.0. At this elevation, the pond
water surface is located approximately 30-feet from the existing pedestrian railing at the
back of the existing sidewalk along S.R. 434. At the normal water surface elevation of
28.0, the pond has a maximum depth of 6.0 feet. The pond water surface will vary, with
the elevation rising up 1 to 2 feet after storm events and the elevation dropping below
28.0 during dry periods.
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Figure 1 – Aerial View Looking East
S.R. 434 westbound has a posted speed limit of 50 mph adjacent to the Charter School
site. The typical roadway cross-section consists of 11-foot wide travel lanes (two in each
direction), a four foot paved shoulder / bike lane, curb and gutter (vertical F-curb), 3-foot
wide grass strip, 5-foot wide sidewalk, and a pedestrian railing at the back of sidewalk.
The pedestrian railing is not designed to function as a vehicular guardrail. Along the
Charter School’s pond frontage, the pedestrian railing is at the top of a concrete retaining
wall that elevates the S.R. 434 side up to 4-feet above the Charter School side (see photo
below).
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Figure 2 – Charter School Pond
Figure 3 – Typical Pond Section
Staff has contacted the Florida Department of Transportation and the Charter School’s
design engineer-of-record regarding the possible consideration for a vehicular guardrail at
this location. Please see the attached e-mail correspondence (Attachment A) from Mark
Robinson, P.E., the FDOT District 5 Constructability and Design Services Engineer in
DeLand. Based on the information provided, Mr. Robinson indicated that it does not
appear from a highway safety standpoint that any additional shielding along State Road
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Agenda Item #106
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434 is required. The top of bank for the retention pond that is being constructed as part
of the school construction appears to be a minimum of 35 feet from the edge of travel
lane and is outside the clear zone for this section of State Road 434. FDOT also has
criteria for protection of canal hazards that are along a highway, however since the
proposed retention pond only has approximately 540 feet adjacent to the State Road 434
frontage it is not considered a canal hazard (which requires a minimum of 1,000 feet
adjacent to the roadway) and thus does not require any additional shielding. Mr.
Robinson also noted that a guardrail would likely be discouraged by FDOT unless the
conditions met the minimum criteria for warranting a guardrail. The design engineer for
the Charter School expressed a desire to obtain input from FDOT highway design staff at
the District 5 office in DeLand before further evaluating this issue.
Guardrail options: Staff reviewed existing guardrails on nearby state and county roads.
Several are shown below to provide a general idea of some of the options that could be
considered at this location.
Figure 4 – Existing Barrier Examples
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Guardrail costs: The costs to furnish and install guardrails and concrete barriers vary
widely depending on the type of barrier, desired appearance, and the specific design
conditions. A simple metal guardrail can cost in the range of $15 to $25 per linear foot
based on current FDOT cost indexes, while the cost of concrete barriers and more
complex guardrails can be $300 or more per linear foot. At the Charter School, if a
guardrail were to replace the existing pedestrian railing it would likely be more complex
due to the existing retaining wall that could have to be modified or replaced if a barrier
was installed in place of the pedestrian railing. With an approximate length of 500 feet
along the pond frontage and an assumed unit cost of $100 per linear foot, the total cost
would be $50,000. This cost could be much higher depending on the type of guardrail or
barrier required and any aesthetic enhancements. The cost lower if a metal or concrete
guardrail were to be installed at the back of the existing curb, similar to the photo above.
Next Steps:
At this time FDOT does not believe a guardrail is warranted at this location and
installation of a guardrail would be discouraged because a guardrail would be an
unnecessary hazard. Staff is continuing to gather information on this issue and will
provide an update if necessary at the March 28, 2011 City Commission meeting.
FISCAL IMPACT:
This agenda item is for information only and has no fiscal impact.
COMMUNICATION EFFORTS:
This Agenda Item has been forwarded to the Mayor and City Commission; City
Manager; City Attorney/Staff; placed in Press Packets; placed in the City Hall (Lobby) City
Commission Meeting binder; and is available on the City’s Website, LaserFiche, and the City’s
Server. Additionally, information related to this Agenda Item has been sent to media/press
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Agenda Item #106
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representatives who have requested Agendas/Agenda Item information, all Homeowner’s
Associations on file with the City, all individuals who have requested Agendas/Agenda Item
information, Department Directors; and also posted outside City Hall; posted inside City Hall
with additional copies available for the general public; and posted at five (5) different locations
around the City.
RECOMMENDATION:
Staff recommends that the City Commission review and accept the information in this
agenda item.
ATTACHMENTS:
1.Attachment A – e-mail from FDOT dated March 18, 2011
2.Attachment B – Charter School Site Plan
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