Attachment_4A_-_2021_LCYA0298_UWRpt.pdf

Lower Cibola Bridge Inspection Report

Bridge elevation looking upstream (2019)

Structure Information

Inspection Type: Underwater Maintained By: Reclamation Hart Mine Road OVER Colorado River

Colorado River Front Work & Levee System Project Lower Colorado Region Yuma Area Office

NBI #: 0304-0001 RBI #: LCYA0298

Date of Inspection: 1/15/2021 Date of Last Inspection: 1/8/2016

Bridge Name: Lower Cibola Bridge Inspection Date: 1/15/2021 NBI #: 0304-0001 Yuma Area Office

Inspection Information Inspection Members: Dustin Johnson, Caireen Ulepic, Corey Dickson, Jeff Lynn, Seth Ostrowski, Carl Lund, and John Reid Attendees:

Time of Inspection: 9:00 AM Temperature: 65°F Weather Description: Sunny Legal Description and Coordinates Aliquot Part:

NW1/4

Section:

Township:

1S

Range:

23W

Meridian:

Salt and Gila River

Latitude: 33.3032 Longitude -114.6780

Bridge Description

The Lower Cibola Bridge is located approximately 22 miles southeast of Blythe, California, in La Paz County, Arizona. The bridge is inside the Cibola National Wildlife Refuge and carries Hart Mine Road over the Colorado River. The bridge also spans over two unpaved public roads, one on each riverbank. The eight-span bridge is 557 feet long. The deck is 23 feet wide (out-to-out) with a 20-foot-wide roadway.

Seven of the eight spans are constructed of three AASHTO Type III precast/prestressed beams with a CIP reinforced concrete deck. The concrete deck, bridge railing, and deteriorated timber pile bracing were replaced, and deteriorated piles were encapsulated with a barrier wrap in 2011 (AZ BOR CIBR 900(1) - Cibola Bridge Deck Replacement Project). Spans 2, 3, 4, and 5 are each 72’-4” long; span 7 is 69’-10” long; spans 1 and 8 are 69’-8” long. Span 6 is 47’-9” long and consists of five removable, steel panels, consisting of two wide-flange beams (27WF84) with an open steel grating deck, equally spaced at 4’-4½” on centers. All eight spans are simply supported. Bents 1 thru 5, 7 and 8 consist of 18 timber piles with a CIP reinforced concrete cap. Bent 6 is placed adjacent to Bent 7, but the two bents are structurally independent; bent 6 is supported on 9 timber piles with a CIP reinforced concrete cap. The bridge railing is constructed of tubular steel rails connected to steel posts bolted to the top of the curbs.

The bridge is oriented in the east-west direction. The river flows from north to south. The bridge is documented on as-built drawings from left to right, looking downstream.

Report Approval Team Leader: Dustin Johnson, PE Reviewer: Kevin Tibbs, PE

X Team Leader

Reviewer

Approver: Richard Eastland, PE

Approver

Critical Findings Was a Critical Finding identified during this inspection? No If yes, describe the Critical Finding:

NA

Critical Finding Plan of Action

If a Critical Finding was identified, what is the required Plan of Action to correct the issue?

NA

Structural Evaluation Summary

The bridge substructure was in satisfactory condition. No structural defects were observed during the underwater inspection. Plastic wrapping on Bents 2 and 6 were either loose or missing. Recommendation 2019-3-E remains incomplete.

The channel thalweg meanders between the reinforced canal banks of the river channel. This meandering section is approximately 10 feet in depth and 50 to 70 feet across. The thalweg crosses the bridge under Span

2. The channel has experienced gradual aggradation across 80 percent of the channel. Local scour was observed at Bents 3 through 6. The scour holes ranged from 6 to 18 inches below the adjacent stream bed.

The table below shows the approximate elevation of the stream bed at the upstream pile of each bent.

Bent # 1 2 3 4 5 6/7 8 Streambed elev. (ft) 207 198 207.5 207.5 207.5 207 207.5 Scour elev. (ft) - - 206 207 207 205.75 - Original elev. (ft) 201.5 201.5 201.5 201.5 201.5 201.5 201.5 Change (ft) 5.5 -3.5 4.5 5.5 5.5 4.25 6 Pile tip elev. (ft) 168.0 158.0 160.5 161.0 163.0 164.5 168.0

Table 1: Approximate streambed elevations at leading pile of each bent. Datum: Top of Bent = 234.0 ft.

Recommendations and Estimated Costs Definitions Category 1 Recommendations involving the correction of severe deficiencies where immediate responsive action is required to ensure structural safety and operational integrity of a facility.

Category 2 Recommendations covering a wide range of important matters where action is needed to prevent or reduce further damage or preclude possible operational failure of a facility.

Category 3 Recommendations covering less important matters but believed to be sound and beneficial suggestions to improve, or enhance, the O&M of a project or facility.

Status of Previous Incomplete O&M Recommendations Number Description Cost Scheduled

Completion Status

2019-3-E Replace broken plastic ties securing protective covering at wooden piles.

$25,000 FY23 Incomplete

New or Modified O&M Recommendations None

Dive Plan

Dive operations supported by two motorboats (LC Clapper Rail and LC Flannel Mouth). Launch ramp located

6.5 miles upstream of bridge (west side). Bank access into the boat was possible on the west end of bridge, at Bent 1 for boarding on-site.

Inspection scheduled during low flow conditions. Lowest flows are typically on Fridays. Low water conditions resulted in shallow conditions at launch ramp and in river channel.

Divers inspected Spans 3 through 7 by wading. Span 2 and Bent 2 inspected using SCUBA techniques starting at the front pile and moving downstream.

Additional Inspection Notes and Deficiencies

Field Inspection Report Condition Rating Codes for Items 58-62 N Not Applicable 3 Serious Condition – loss of section, deterioration, spalling, or scour have seriously affected primary structural components.

Local failures are possible. Fatigue cracks in steel or shear cracks in concrete may be present

9 Excellent Condition 8 Very Good Condition – no problems noted.

7 Good Condition – some minor problems.

2 Critical Condition – advanced deterioration of primary structural elements. Fatigue cracks in steel or shear cracks in concrete may be present or scour may have removed substructure support. Unless closely monitored it may be necessary to close the bridge until corrective action is taken.

6 Satisfactory Condition – structural elements show some minor deterioration.

5 Fair Condition – all primary structural elements are sound, but may have minor section loss, cracking, spalling, or scour

1 “Imminent” Failure Condition – major deterioration or section loss present in critical structural components or obvious vertical or horizontal movement affecting structure stability.

Bridge is closed to traffic, but corrective action may return structure to light service.

4 Poor Condition – advanced section loss, deterioration, spalling, or scour

0 Failed Condition – out of service; beyond corrective action.

Condition Rating Code Equivalents for Sub-Components G = Good (7-9) F = Fair (5-6) P = Poor (0-4) N = Not Applicable UNK = Unknown 60 Substructure Condition 7 - Good Piers Notes (with Sub-Component Number):

60.19 – Plastic bands securing the protective wrapping to the timber piles have failed (approximately 1/3 of the piles). No wrap on Bent 2 piles.

1. Walls and/or Columns N

2. Piles G

3. Caps and/or Bearing Seats G

4. Foundations G

5. Erosion and/or Scour G

6. Settlement or Deflection G

7. Other - Wrap F

61 Channel and Channel Protection Condition 8 - Very Good

1. Alignment G Notes (with Sub-Component Number):

61.2 – River cross section indicates general aggradation across 80 percent of channel. Local scour holes around leading piles, Bents 3 – 7.

61.3 – Banks protected by vegetation and rip rap.

2. Erosion and/or scour G

3. Channel Protection G

4. Waterway Obstructions G

5. Adequacy of Opening G

6. Streambed Composition G

7. Other

Scour Critical Bridges Every bridge should have a scour evaluation report on-file that documents the code for Item 113 – Scour Critical Bridges. Every routine inspection should verify that the Item 113 code is still valid.

Item Current

Rating Valid?

(Yes/No)

Notes

113 – Scour Critical Bridges

5 Yes Scour evaluation report dated June 2020.

Structure Inventory & Appraisal (1 of 2)

Structure Inventory & Appraisal (2 of 2)