HomeMy WebLinkAboutRUDOLPH FARMS INFRASTRUCTURE PROJECT - FDP220010 - SUBMITTAL DOCUMENTS - ROUND 5 - VARIANCE REQUEST (2)
NORTHERNENGINEERING.COM | 970.221.4158 VARIANCE REQUEST: RUDOLPH FARM
FORT COLLINS | GREELEY 1 | 2
VARIANCE REQUEST
March 9, 2023
City of Fort Collins
Development Review
281 N College Ave.
Fort Collins, CO 80524
RE: RUDOLPH FARM PROJECT
LCUASS VARIANCE REQUEST – MINIMUM DEPTH OF UTILITIES
NORTHERN PROJECT #1896-001
City staff:
Northern Engineering would like to present this variance request for the Rudolph Farm project. General
information about the project is presented below, and detailed information about the nature of this request
follows.
General Information
The project site is located at the northeast corner of Prospect Road and I-25 in Fort Collins. The site
currently is used for agriculture, and this project is slated to develop multi-use “super-pad” sites which will
include, commercial, retail, and residential developments. The entire project site consists of approximately
115 acres.
Depth of Utilities
Section 12.2.2 in LCUASS states that "All utilities shall be located at least 2 feet below the scarified subgrade
elevation, unless specifically approved to be less by the Local Entity Engineer.”
Because there is very little vertical fall across the site, maintaining a full 24" of cover at all flowline locations
is impossible while achieving positive flows through pipes throughout the site and connecting to the outfall
connection point(s) south of the site (specifically, the invert elevation of the Lake Canal Ditch south of
Prospect Rd.)
The current design includes two locations with cover at flow lines less than 24" (shown in the attached
figure):
1. Proposed Storm line G, (15" RCP) features 17.7" min. of cover at the Carriage Pkwy flowlines.
2. The proposed Lake Canal box culvert (15'x4' RCB) under Prospect Rd features 17.4" of cover at the
north flowline.
We are requesting a variance to the above-mentioned utility depth requirement at the two locations
described above, and are proposing a minimum cover requirement of 17” for both locations as described
above. The roadways in these two locations have been redesigned following discussions with City staff to
increase the cover over the pipe/concrete box.
In terms of existing capital and maintenance requirements, the proposed design alternative does not
adversely affect any other LCUASS requirements. Maintenance costs or requirements and design life are
not expected to be adversely affected at either location; the 17” minimum still falls within the minimum
design depth needed under a roadway for a 15” RCP to maintain structural integrity and distribution of
downward forces within the surrounding ground will still occur. The box culvert is being designed to meet
AASHTO M 273 specifications, or equivalent ASTM Standard C 1433, for vehicle traffic, to allow for less than
2-feet of cover on top.
NORTHERNENGINEERING.COM | 970.221.4158 VARIANCE REQUEST: RUDOLPH FARM
FORT COLLINS | GREELEY 2 | 2
VARIANCE REQUEST
No detriment to public health, safety, or welfare is expected to occur with this design variance due to the
fact that adequate cover still remains over the 15” RCP, and the box culvert is being designed/constructed
to a higher standard in terms of structural integrity and design life. These public elements will be greatly
improved upon by the amenities brought upon by this project, and th e project would not be able to be
completed without these two design alternatives because positive drainage could not be achieved from
the site.
Thank you for your consideration and attention to this request.
If you have any questions, please feel free to contact me directly.
Sincerely,
NORTHERN ENGINEERING SERVICES, INC.
AUSTIN SNOW, PE
Project Engineer