Report_4_-_Choctaw_Lake_Bridge_Inspection_Report_2012.pdf

NFSR 967 MP 1.20

STRUCTURE ID NUMBER: SA 10 000000000 014

BRIDGE NAME: NFSR 967 over Choctaw Lake Spillway

LOCATION: Tombigbee National Forest

Tombigbee District

Choctaw County, Mississippi

BRIDGE LENGTH 76 FT (19-19-19-19)

INSPECTION DATE: March 9, 2012

INSPECTED BY: ETS Enterprise Team and

Tombigbee Ranger District

Thomas H. Laurent Jr., Civil Engineer

James "Bo" Newman, Engineering Tech.

Ralph Deweese, Engineering Tech.

PREPARED FOR: USDA Forest Service

National Forests in Mississippi

PREPARED BY:

USDA Forest Service

ETS Enterprise Team

Written By: THL

Reviewed By: SB

OWNER OF THE BRIDGE: USDA Forest Service

DATE SUBMITTED: June 2010

27/(2- Date: Thomas H. Laurent Jr.

Civil Engineer

Steve Bingham, P.E. Date:

Forest Engineer

The condition data and recommendations contained within this report are based on a visual inspection of accessible portions of the existing structure. No responsibility is accepted for the existence of latent defects that cannot be detected during visual inspections.

Table of Contents

I. Orientation

II. Significant Findings

III. Structural Analysis/Load Rating

IV. Inspection Frequency

V. Recommendations

VI. Photographs/Drawings

VII. Field Notes/ Bridge Inspection Report

VIII. Stream Cross Section

IX. Updated SI&A Sheets

Bridge No. SA 10 00000000 014 Inspection Date: 02/26/2010 FS RD. #967 MP: 1.20 Over Choctaw Lake Spillway Tombigbee National Forest Choctaw County, Mississippi Tombigbee District

I. Orientation:

All directions for this Inspection are based on a person facing downstream. The directions right and left refer to the person’s right and left respectively. Upstream and downstream are based on the direction of flow of the stream. To correlate these directions with previous inspection reports, the right end of the bridge corresponds with the far end, the left end corresponds to the near end of the bridge, the upstream side of the bridge refers to the right side of the bridge, and the downstream side of the bridge corresponds to the left side of the bridge.

Girders in this report are numbered from the upstream side to the downstream side, which is reversed with respect to the numbering system in the previous report. The spans are numbered from the left to the right in this report which is identical to the previous report.

Substructure components are numbered from the left to the right in this report which is identical to the previous report. Bridge rail posts are numbered from the left end.

II. Significant Findings:

Overall the bridge is in fair shape (SI&A condition rating 6.) The most significant observed defects are noted below. (refer to the Bridge Inspection Report, included after the photos, for additional findings and detail):

Settlement on both approaches. Settlement is averaged 56” side on the left abutment and averages 1” deep. The settlement is up to 4” deep for 30” from the upstream curb. Settlement has occurred in the past. Evidence of asphalt patching to resolve problem. Up to 1” settlement on the right end of the bridge full width.

There is a 9” diameter hole in the fill at the upstream left corner of the bridge. The hole is 2.3’ deep.

Approach rails are not long enough along the road, do not have enough posts for a proper transition, and have substandard blunt ends.

Two bridge sections on the upstream rail sound hollow. Evidence of moderate decay up to 1” deep for the entire top surface of the both the upstream and downstream bridge rails.

Vegetation growing out of one section of the downstream bridge rail. Hairline cracks due to shrinkage and decay in several locations on the downstream bridge rail.

Two bands of chip seal material on the left end of bridge, almost the full width of the bridge.

Material appears to be from not cleaning up the run out material when the left approach was chip sealed.

The grout between girders 3 and 4 of span2 and girders 4 and 5 of span 3 is cracked.

The holes for the pin connecting the girders and the cap beam are not grouted at the left end of girder 2 in span 2, at the right end of girders 3, 4, and 5 of span 4.

All bolts between spans are loose.

Numerous minor spalls and chips on the girders, fascia beams, and cap beams scattered throughout the structure. Most are due to inadequate cover on the stirrups and the horizontal reinforcing in the diaphragms. All exposed reinforcing steel is rusty with pack or laminate rust developing on reinforcing in spots.

All cap beams have a vertical crack in the middle of the cap beam. The crack is in either the upstream and/or the downstream end of the cap beam.

Pile B in the upstream wingwall and Pile D of the downstream wingwall of the left abutment sound dull.

Piles 1 and 2 of the left abutment sound hollow. Pile 5 of the left abutment is severely decayed at ground level with 4” of penetration with the scratch awl.

The top end of pile 1 in bent 1 is rotten for 9” and sounds hollow. The pile also has a 2.5”x 8” shake at the concrete, or mud line. Piles 3, 4, and 5 also sound hollow.

Pile 5 in bent 2 sounds dull for 3 feet above the mud line, pile 4 sounds hollow.

Pile 1 in bent 3 has visible rot in the top 6” of the pile. The pile is no longer in full contact with the concrete cap beam due to the visible decay. The same pile sounds hollow for the first 18” above the mudline. Piles 3 and 4 are sounding hollow, and pile 5 is hollow.

Planks 1 and 4 of the upstream left wingwall are rotten and breaking up. The downstream end of plank 2 in the back wall is rotten. The planks of the backwall above the cap beam are severely decayed.

The upstream wingwall plank 3 and downstream wingwall plank 2 are rotten. The rest of the planks look sound.

The spillway is concrete lined and has failed along the right bank approximately 50’ from the downstream end of the spillway. There is a hole estimated at least 5’ diameter in the spillway with water disappearing into the hole and into the right bank at that point. I was unable to get close enough to get a definitive measurement for safety reasons, due to the force of the water flowing into the hole and along the spillway.

III. Structural Analysis Structural deficiencies that would cause the load rating to be affected were noted in the substructure. Until a new load rating can be performed, the load ratings from the previous SI&A sheet are still valid. The previous load ratings are:

Allowable Stress Method HS‐20 (U.S Tons)

Required Posting (U.S. Tons)

Inventory Rating 33.8 N/A

Operating Rating 51.3 None Required

IV. Inspection Frequency There is evidence of serious deterioration or other problems in the substructure that warrant placing the bridge on a shorter inspection cycle. Therefore, it is recommended that the bridge be placed on a 12 month inspection cycle.

V. Recommendations Repairs:

Item Estimated Quantity

Install adequate approach rail sections, ends, and post spacing meeting current standards.*

100 LF

Repair or replace the decayed sections of the bridge rail. 4 EA

Remove the excess chip seal material from the bridge deck. 1 EA

Tighten all bolts between spans. 21 EA

Clean and patch the spalled areas on the beams <1 CY

Repair or replace piles A, D, 1, 2 and 5 in the left abutment, pile 1, 3, 4, and 5 in bent 1, piles 4 and 5 in bent 2, and piles 1, 3, 4, and 5 in bent 3.

15 EA

Replace the back walls and wing walls. 6 EA

Consider filling the scour hole with appropriately sized riprap as an energy dissipater for the water coming off of the spillway and out of the siphons.

1 EA

Repair or replace the damaged portions of the spillway 1 EA

Consider replacing the entire bridge and spillway. 1 EA

Conduct a special inspection of the substructure at 12 month intervals. 1 EA

Note*: The 2001 AASHTO Guideliines for Geometric Design of Very Low‐Volume Local Roads should be referenced as to the extent of repairs necessary for the approach rail sections.

Bridge No. SA 10 00000000 014 Inspection Date: 03/09/2012

Photo No 1. Upstream Elevation. Note superstructure is obscured by parallel pedestrian bridge.

Photo No 2. Downstream Elevation

Photo No 3. Bridge from the Left Approach

Photo No 4. Bridge from the Right Approach

Photo No 5. Looking upstream from the Pedestrian Bridge Deck

Photo No 6. Looking Downstream from the Bridge Deck

Photo No 7. Upstream end of the Left Abutment.

Photo No 8. Downstream end of the Left Abutment.

Photo No 9. Upstream end of the Right Abutment.

Photo No 10. Downstream End of the Right Abutment.

Photo No 11. Upstream End of Bent 1, Right Face (Tyoical.)

Photo No 12. Downstream end of Bent 1, Right Face (Typical.)

Photo No 13. Pile 5 Right abutment. Note the scratch awl 4” penetration depth.

Photo No 14. Pile 3 of Bent 1. Note the hammer.

Photo No 15. Rot in the upstream Rail at the centerline of the spillway.

Photo No 16. Typical rot in the bridge rails, centerline of stream downstream rail.

Photo No 17. Typical hairline cracks (Girder 5, Span 4.)

Photo No 18. Typical exposed end diaphragm reinforcing steel (Girder 6, Span 3, Right End.)

Photo No 19. Crack in Cap Beam 1 at Pile 4 0.020” wide.

Photo No 20. Crack in the downstream end of Cap Beam 3.

Photo No 21. Crack in the Upstream end of Cap Beam 2.

Photo No 22. Broken End Diaphragm on Girder 7 of Span 1.

Photo No 23. Fill missing from behind the grouted rock wall at the right abutment.

Photo No 24. Large Scour Hole at the Downstream end of the Spillway.

Photo No 25. Collapsed and Failed Spillway and Right Bank Grouted Rock Wall.

Photo No 26. Approximate 5’ to 6’ drop off of the Downstream End of the Spillway.

Forest: Tombigbee District: Tombigbee

Road: 967 Mile 1.20

Bridge: SA 10 000000000 014

Girder Depth: 2'-2.5" = 2.2 Feet Measured from the top of the curb.)

Cross-section at the upstream side of the bridge.

Location from Left End Depth to Stream Bed Depth to Water Surface From top From Bottom From top From Bottom

Decimal of Curb of Girder of Curb of Girder Ft In Feet Feet Feet Feet Feet

0 0 0.0 4.50 2.30 2 11 2.9 7.60 5.40 9 11 9.9 9.45 7.25

15 5 15.4 9.45 7.25 21 11 21.9 9.45 7.25 28 11 28.9 9.55 7.35 34 5 34.4 9.55 7.35 40 11 40.9 9.65 7.45 46 6 46.5 9.75 7.55 9.50 7.30 53 5 53.4 9.60 7.40 59 11 59.9 9.55 7.35 65 6 65.5 9.55 7.35 72 5 72.4 9.00 6.80 76 0 76.0 4.00 1.80

Forest: Tombigbee District: Tombigbee

Road: 967 Mile 1.20

Bridge: SA 10 000000000 014

Girder Depth: 2'-2.5" = 2.2 Feet (Measured from the top of the curb.)

Cross-section at the downstream side of the bridge.

Location from Left End Depth to Stream Bed Depth to Water Surface From top From Bottom From top From Bottom

Decimal of Curb of Girder of Curb of Girder Ft In Feet Feet Feet Feet Feet

0 0 0.0 4.30 2.10 2 10 2.8 5.30 3.10 9 10 9.8 6.55 4.35

15 5 15.4 9.65 7.45 21 11 21.9 9.75 7.55 28 10 28.8 9.85 7.65 34 5 34.4 9.90 7.70 40 11 40.9 10.00 7.80 9.70 7.50 46 6 46.5 10.00 7.80 53 6 53.5 10.00 7.80 60 0 60.0 9.90 7.70 65 6 65.5 8.90 6.70 72 5 72.4 4.40 2.20 76 0 76.0 3.65 1.45