HomeMy WebLinkAbout990794.tiff STATE OF COLORADO
DEPARTMENT OF TRANSPORTATION
Design and Construction Branch .OT
E.Arkansas Avenue,Room 320
•Denver,Colorado 80222
(303)757-9309 FAX(303)757-9197 DEPARTMENT
April 5, 1999
Ms. Connie Harbert
Commission Chair
915 10th Street
Greeley, CO 80632
RE: Spring 1999 list of scour vulnerable bridges and bridges in your jurisdiction that have unknown
foundations.
Dear Ms. Harbert:
Attached for your information, as we approach the spring runoff season, is a table listing the structures in your
jurisdiction that have been determined to be scour critical, or have unknown foundations, or were otherwise
recommended for monitoring during high water by your bridge inspection consultant.
This assessment was required by the Federal Highway Administration and the results of the assessment are
included as Item113 of the National Bridge Inventory database. The following describes the recommended
actions for the corresponding values of Item113.
If:
Item113 =0.0. These bridges are scour critical, have failed and are closed to traffic.
Item113 = 1.1. These bridges are scour critical and field inspection indicates that failure is imminent. In this
condition, the bridge must be closed.
Item113 = 2. These bridges are scour critical. Field review indicates that extensive scour has occurred. Im-
mediate action is required to provide scour countermeasures. These bridges should be closed or monitored
closely during, and alter, a high water event.
Item113 = 3. These bridges are scour critical. The foundations have been determined to be unstable for the
calculated scour conditions. These bridges should be monitored closely during, and after, a high water event
or closed if monitoring is not feasible.
Item113 = U. These Bridges have unknown foundations and, per FHWA guidelines, are assumed to be scour
vulnerable and require monitoring, or closure, during a high water event.
If:
Item113 = 4. These bridges have been determined to be stable for calculated scour conditions BUT, field re-
view indicates action is required to protect exposed foundations from effects of additional erosion and corro-
sion. These bridges should be inspected for additional scour after a high water event.
Item113 = M. This code is only used by Colorado. It identifies those bridges that do not fit the condition
codes listed above but, based on your consultant's judgment, they are recommended for monitoring during,
and after, a high water event.
o ,, -L A . • - 17R -`,7 C C. Ea- 990794
During a high water event, we suggest that you:
1. Close the bridge immediately if anything looks out of the ordinary or if any of the following indications
of scour occur:
• Sagging spans, and/or
• Settled or out-of-plumb piers or abutments, and/or
• Sagging. distorted, or out of alignment bridge rail, and/or
• Washing-out of fill behind the abutment and under the roadway or approaches, and/or
• The development of a dip in the deck.
2. Remove debris from piers and abutments as it accumulates, if possible.
3. Inspect, or call us or your consultant to inspect, the structure after the flow subsides. Look for the
same kinds of indications mentioned above and for newly exposed footings, new or additional scour,
or a build up of debris that can hide problems.
4. Check bridges that have temporary shoring to be sure that the shoring is still in place and functioning
as intended.
5. Monitor bridges that have large amounts of debris accumulated before the high water started even if
they are not on this list.
Bridges that are not on the attached list but that you know from experience are vulnerable during high water,
should also be handled appropriately. You may want to inform your consultant that you want Item113 coded
"M"to indicate that these bridges require monitoring and you would like them to be included in the scour list.
Please remember that the consultant only sees your bridges for a brief time every two years. Your staff has
the best knowledge of the overall situation and we want their input so that our data can reflect the flooding
conditions they see as accurately as possible.
I hope this information is helpful to you. If you have questions, please don't hesitate to call your bridge in-
spection consultant, Harding Lawson Associates (HLA), (303)-295-1599, or Walter Mystkowski, CDOT's
Bridge Management Engineer, at (303) 757-9188.
Sincerely �,�%
Stephen W. Horton, P.E.
Design and Construction Engineer
BRIDGES IDENTIFIED AS SCOUR CRITICAL AND/OR SUGGESTED
FOR MONITORING DURING FLOODING
COUNTY OF WELD
INSPECTED BY HLA
USING DATA AS OF 03/30/1999
SPAN ITEM
BRIDGE NUMBER FEATURE INTERSECTED ROAD CARRIED /TYPE 113
WEL016.5-001. OB BOULDER CREEK COUNTY ROAD 16. 5 2-CDTPG 2
WEL029.0-062 .OB CACHE LA POUDRE RIVER COUNTY ROAD 29 2-CPGC 2
WEL044 . 0-009. OA LITTLE THOMPSON RIVER COUNTY ROAD 44 1-SSM 2
WEL045. 0-058.5B CACHE LA POUDRE RIVER COUNTY ROAD 45 3-CDTPG 2
WEL077. 0-092 . OA CROW CREEK COUNTY ROAD 77 1-SSM 2
WEL126. 0-019. OA LONE TREE CREEK COUNTY ROAD 126 2-SSMC 2
WEL043 . 0-070. 0B LONE TREE CREEK COUNTY ROAD 43 1-SSM 3
WEL054 . 0-013 . OA BIG THOMPSON RIVER COUNTY ROAD 54 2-CDTPG 3
WEL054 . 0-041. OA SOUTH PLATTE RIVER COUNTY ROAD 54 11-CDTPG 3
WEL020. 5-003 . OB BOULDER CREEK COUNTY ROAD 20. 5 2-SSM 4
WEL027 . 0-062 . 1B CACHE LA POUDRE RIVER COUNTY ROAD 27 2-CDTPG 4
WEL034 . 0-017 . OA ST. VRAIN CREEK COUNTY ROAD 34 6-CDTPG 4
WEL035. 0-062 . OA CACHE LA POUDRE RIVER COUNTY ROAD 35 2-CDTPG 4
WEL052 .0-033 . OA ASHCROFT DRAW 49TH STREET 1-CDTPG 4
WEL061. 0-054 . OB DIVER. OF S. PLATTE RIVER COUNTY ROAD 61 2-CDTPG 4
WEL067 . 0-128 . OA SIMPSON CREEK COUNTY ROAD 67 1-SSM 4
WEL068.0-083 . OA SANBORN DRAW COUNTY ROAD 68 1-SSE 4
WEL120. 0-085. OA CROW CREEK COUNTY ROAD 120 1-SSM 4
Hello