HomeMy WebLinkAboutMONTAVA - PHASE G & IRRIGATION POND - BDR210013 - DOCUMENT MARKUPS - ROUND 4 - VARIANCE REQUEST (2)
November 15, 2022
Tim Dinger
Engineering Department Manager
281 North College Avenue
Fort Collins, Colorado 80524
RE: Montava Roundabout Roadway – Material Variance Request
Dear Mr. Dinger,
Variance Request: Asphalt Pavement in lieu of Concrete Pavement for the Proposed Roundabout at
Mountain Vista Dr. and Timberline Road
Issue Identification:
The Montava Phase G Roadway Plan includes deviations from the required circulating roadway concrete
pavement type as outlined in Appendix I – Fort Collins Roundabout Design Manual to the Street Design and
Technical Criteria. Specifically, section B.3, Local Entity Engineer approval is requested for the use of asphalt
pavement material.
Proposed Alternate Design:
The proposed material type for the proposed roundabout is asphalt pavement based on the following
justification:
1. Concrete joint patterns can contradict pavement markings and can confuse drivers. Asphalt has no
surface joints, and thereby avoids this issue.
2. White and yellow pavement markings show better contrast when applied on dark asphalt pavement
versus lighter colored concrete pavement. This helps drivers identify the markings easier.
3. Asphalt initial construction costs are expected to be lower and allow for more construction phasing
flexibility when being constructed.
4. Mountain Vista is currently a truck route which can require additional maintenance. For this reason,
asphalt is typically more cost effective and an easier material for maintenance crews to work with.
5. Thermoplastic pavement marking more easily rub off concrete material and require additional
maintenance costs.
6. Long term maintenance for the water lines, sanitary sewer, No. 8 ditches and other utility infrastructure
under the intersection makes asphalt a more cost-effective material than concrete for future repairs.
7. A stiff asphalt pavement mix design will be coordinated with the Geotechnical Engineer to mitigate any
concerns with rutting and shoving that can be experienced with asphalt pavement material when
centrifugal forces are applied due to truck and bus traffic circulating through the roundabout.
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There is no foreseen adverse impact to capital and maintenance costs relating to this variance request.
This variance is not foreseen to be detrimental to the public health, safety, and welfare nor reduce the
design life of the improvement.
Respectfully,
Deborah Alvarado, PE