Bridge_Inspection_ _Load_Analysis_O-11_Bridge.pdf

BRIDGE INSPECTION AND LOAD ANALYSIS

OF

O-11 BRIDGE

FOR

MALMSTROM AFB, MONTANA

JOB NO: 08-099

Great Falls ● Bozeman● Kalispell, Montana Spokane, Washington ● Lewiston, Idaho

AUGUST 2008

Great Falls ● Bozeman● Kalispell, Montana

Spokane, Washington ● Lewiston, Idaho

CSW

Neil

EXECUTIVE SUMMARY

O-11 Bridge – Executive Summary Page - 1 of 3 tdh #08-099

AGENCY: Malmstrom AFB, Montana

CONTRACT NO. FA 4626-08-P-0019

ENGINEER: Thomas, Dean and Hoskins, Inc., Great Falls, Montana

Project Manager: Neil Curry, P.E.

Bridge Inspection Leader: Bill Lloyd, P.E. (Great West Engineering)

Load Rating Calculations: Brian May, P.E.

Garrett Drake, EI

Final Review and Quality Check: Neil Curry, P.E.

Completion Date: August 6, 2008

BRIDGE LOCATION:

Missile Launch Facility O-11

Fergus County, Montana

Crosses Armell’s Creek approximately 25 miles northeast of Lewistown, approximately 8 miles off of US HWY 191.

GOVERNING CODES:

Manual for Condition Evaluation of Bridges, 2nd Edition.

AASHTO 17th Edition Bridge Design Specifications, 2002.

DESCRIPTION OF WORK:

Thomas, Dean and Hoskins, Inc., was contracted to complete this work on June 23, 2008. In general, the Statement of Work required the following:

NBIS Bridge Inspection with report.

Load Rating/Calculations providing Inventory and Operating Rating for the standard AASHTO Load Rating Vehicles and also the MCL Transporter-Erector Vehicle.

Executive Summary describing the bridges, inspection notables, and load rating results.

O-11 Bridge – Executive Summary Page - 2 of 3

BRIDGE SUMMARY

BRIDGE CHARACTERISTICS:

3-span timber bridge, 16’ wide one lane, crossing small waterway.

21’ long spans throughout = 63’ total bridge length.

Stringers: 8”w x 18”d, spacing varies 2’-2” to 2’-6”.

Abutments: Timber cap on timber piles, with timber backwall/wingwall.

Intermediate Piers: Timber cap on timber piles.

Deck: 2”x6” on end. No running planks. Some loose gravel surfacing (road mix) on deck, 3” thick in isolated locations.

Timber guide rail each side, with timber wheel guard.

GENERAL INSPECTION INFORMATION:

All bridge elements rated in GOOD condition except the following rated in FAIR condition:

o Bridge railings and curbs.

o Timber decking.

o Bridge drains and deck drainage.

Other notable inspection information:

o Railing is weathered and checked.

o Decking has significant wear in isolated locations.

o Moderate checking and minor damage within timber stringers.

o Timber diaphragms (between beams) have some damage.

Inspection did identify an element that reduced the load rating capacity of the bridge. This element was the decking planks, which were observed to have approximately 1¾” of wear in isolated locations. Although this significantly reduces the capacity of the deck, the overall load rating was only impacted slightly since the bridge stringers had similar rating capacity as the deck.

See Inspection Report for more detailed information and repair recommendations.

REPAIR REQUIREMENTS:

Repair recommendations are given within the Inspection Report.

The deck condition is reducing the load rating of the bridge, and is the only condition that is considered a capacity issue. The deck should be monitored to ensure no further wear or deterioration occurs. The installation of running planks should be considered.

O-11 Bridge – Executive Summary Page - 3 of 3

LOAD RATING SUMMARY:

The Load Rating does not require restrictions for any of the four design trucks analyzed.

Deck shear controls the load rating, followed closely by stringer bending (flexure).

No Load Rating issues are identified at this time for the rating vehicles used, including the MCL Transporter-Erector.

LOAD RATING SUMMARY TABLE: O-11 BRIDGE

Inventory Rating (tons) Operating Rating (tons)

Rating Vehicle Stringer Deck Stringer Deck

Flexure Shear Flexure Shear Flexure Shear Flexure Shear

T3 38.1 55.4 47.5 36.1

50.7 73.6 63.3 48.0

T3-S2 60.2 85.0 75.0 57.1

80.0 113.0 100.0 75.9

T3-3 74.0 107.3 80.7 61.4

98.4 142.7 107.6 81.6

T-E 86.9 130.5 134.7 102.6 115.6 173.5 179.5 136.5

1. See the Load Rating Calculations for additional information.

2. T3 trucks are AAHSTO trucks, T-E is the MCL Transporter-Erector (see “Miscellaneous

Information” Section for descriptions of the rating vehicles).

3. All values in tons.

4. Controlling bridge elements are shaded.

5. The “stringer” values for the T-E vehicle do not represent a rating for a total truck weight rating since the truck is significant longer than the span length. Deck values do represent a total truck weight rating.

LOAD RATING:

Inventory Load Rating: 36 tons (does not require posting)

Operating Load Rating: 48 tons

The Inventory Load Rating is the bridge load rating based on repeated loading. The Operating Load Rating is the bridge load rating based on an infrequent loading. Public bridges are typically posted for the Inventory Rating.

The above rating was controlled by the deck for a Type 3 AASHTO Truck, although the stringer capacity was similar in capacity.

The MCL Transporter-Erector vehicle did not control the above Load Rating, and does not require restriction since it falls under the Operating Rating criteria.

INSPECTION REPORTS

(8) NBI Structure Number: L14112007+05001

Structure Name: O-11

Road Name: Irish Road

Feature Intersected: Armells Creek

Location: Fergus County

Agency: MAFB

Geographic and Route Data Dimensionsal Data

1 State Code 308 32 Appr Rdwy Width (ft) 16

2 State Hwy District 5 39 Nav. Vert. Clr (ft) 0

3 County Code 27 40 Nav Horz Clr (ft) 0

4 Place Code 0 48 Max Span Length (ft) 21

6 Feature Under 49 Structure Length (ft) 63

7 Facility On 1 50a Lt Curb/Swlk Width (ft) 1

9 Location 50b Rt Curb/Swlk Width (ft) 1

16 Lattitude 47d23'24" 51 Br Width Curb-Curb (ft) 16

17 Longitude 109d08'12" 52 Deck Width Out-Out (ft) 18

98 Border Bridge 53 Min Vert Over Clr (ft) 99

99 Border Bridge Str No. 54 Min Vert Under Clr (ft) 0

103 Temporary Str 55 Min Lat Under Clr Rt (ft) 99

56 Min Lat Under Clr Lt (ft) 0

On and Under Record Data 112 NBIS Br Length? Y

5 Inv Rte L14112 116 Nav Min Vert Clr (ft) 0

10 Inv Rte Min Vert Clr (ft) 99

11 Inv Rte Mile Post 7.5 Proposed Improvements

19 Detour Length (miles) 75 Type of Work 361

20 Toll 76 Length of Str Imp (ft) 63

26 Functional Class 94 Br Imprv Cost (x1000) 5

28 Lanes on/under 1/0 95 Rdwy Imprv Cost (x1000) 0

29 ADT 100 96 Total Project Cost (x1000) 7

30 Year of ADT 2003 97 Year of Cost Estimate 2008

47 Inv Rte Tot Horiz Clr (ft) 16 114 Future ADT 100

100 Defense Hwy 115 Year of Future ADT 2020

101 Parallel Bridge N

102 Direction of Traffic 2 Condition Ratings

104 Hwy System 1 58 Deck 6

109 Percent of Trucks 59 Superstructure 7

110 National Truck Network 60 Substructure 6

61 Channel 8

General Data 62 Culvert N

13 Appraisal Ratings

21 Maint. Responsibility 2 67 Structural Evaluation 6

22 Bridge Owner 2 68 Deck Geometry 2

31 Design Loading 0 69 Underclearance N

33 Bridge Median 0 71 Waterway Addequacy 8

34 Skew 35 72 Appr Rdw Align 6

35 Structure Flared 0 36a Bridge Rail 0

37 Historical Significance 5 36b Transition Rail N

38 Navigation Control 0 36c Appr Guardrail N

42 Service Type 0-5 36d Appr Guardrail Ends N

43 Str Type, Main 702 113 Scour Critical Rtg 6

44 Str Type, Appr 0

45 Number of Main Spans 3 Load, Rate, and Post

46 Number of Appr Spans 0 41 Open, Post, Close A

27 Year Built 1962 63 Method Used Oper Rtg 5

105 Federal Land Highways 64 Oper Load Rtg

106 Year of Reconstruction 65 Method Used Inv Rtg 5

107 Deck Str Type 8 66 Inv Load Rating

108 Wear Surf Prot System 0 70 Bridge Posting Code 5

111 Nav Pier/Abut Prot

Over 200 Items

Inspection Data 200

90 Inspection Date 7/8/2008 201

91 Inspection Frequency (mos) 24 202

92a Fracture Critical N 0 203

92b Underwater Insp N 0 204

92c Special Insp N 0 205

93a Date Fract Crit Insp 0 209

93b Date Underwater Insp 0 210

93c Date of Special Insp 0 216

Structure Inventory and Appraisal Sheet

Inspection Page 1 of 4

ROUTINE ROAD BRIDGE INSPECTION REPORT

IDENTIFICATION and LOCATION:

Structure Name: O-11

Route: Irish Road Milepost: 7.50

County Fergus MDT District: 5

Feature Crossed: Armells Creek

BRIDGE RATING SUMMARY:

Date: July 8, 2008 Time Started: 10:00 am Time Completed: 12:00 pm

Inspection Team: Bill Lloyd, PE

Weather: 60°, Sunny, Calm, Dry

Rerating required based on current inspection?

Organization:

YES NO (Circle One) N/A Insp Team

Leader:

Signature

RECOMMENDED WORK

TASK ID DESCRIPTION

UNIT

TYPE

UNIT

COST

TOTAL

COST

WEAR SURF

INSTALL LONGITUDINAL RUNNING PLANKS/LEVEL

EXISTING DECK SURFACE

$5,000

58-1 REMOVE ROAD MIX SURFACE FROM BRIDGE DECK $200

58-C4 PAINT BRIDGE RAIL $200

58-C5 CLEAN SCUPPERS $100

60-20 REMOVE DEBRIS ACCUMMULATED ON PIER PILES $100

36-2 INSTALL OBJECT MARKERS $1,000

36-1

INSTALL “SINGLE LANE BRIDGE AHEAD” SIGN ON

NORTH APPROACH

$500

Inspection Page 2 of 4

CONDITION CODES AND REMARKS

CONDITION RATING REMARKS: Abut #1 – SW Abut, Span #1 – SW Span, Girder #1 - Downstream

WEARING SURFACE NO WEARING SURFACE

58. DECK: 6

*1. DECK SLAB/PANELS/JOISTS F 2x6 NAIL LAMINATED, WEAR DEPTH 1-3/4” + AT WHEEL LINES.

60% COVERED WITH ROAD MIX UP TO 3” DEEP

C1. DECK JOINTS

C2. CURBS F DAMAGED AT ABUT #2 UPSTREAM

C3. SIDEWALKS

C4. BRIDGE RAILINGS F WEATHERED AND CHECKED, PAINT GONE ON RAIL. DAMAGE

AT ABUT #2 UPSTREAM

C5. DRAINS AND DRAINAGE F SCUPPERS PLUGGED WITHROAD MIX

C6. RIDEABILITY F

C7. CLEANLINESS P

C8. UTILITIES

59. SUPERSTRUCTURE: 7

*1. GIRDERS 8 LINES. G

A. DIAPHRAGMS G ABUT #1: SPLIT BETWEEN GIRDERS 2 & 3

ABUT #2: SPLIT BETWEEN GIRDERS 1 & 2, 2 & 3

B. BRACING G

*2. FLOOR BEAMS

*3. STRINGERS

*4. TRUSSES

A. CHORDS

B. PORTALS

C. VERTICALS/DIAGONAL

D. BRACING

C1. BEARING DEVICES G PAINTED STEEL CLIP ANGLE

C2. PAINT

C3. DEFLECTION UNDER LOAD NOT OBSERVED

C4. VIBRATION UNDERLOAD NOT OBSERVED

60. SUBSTRUCTURE: 6

A *1. ALIGNMENT (TIPPING, TILTING,...) G ONLY CAP VISIBILE AT ABUT #1

B *2. EROSION OR SCOUR

U *3. SETTLEMENT

T TIMBER ABUTMENTS (INCL. WW)

M *4. CAPS G ABUT #1 CAP CHECKED FULL LENGTH

E *5. POSTS/PILES G ABUT #2: TWO UPSTREAM BATTER PILES OUT OF ALIGNMENT

N *6. BACKING PLANKS G

T *7. SILLS/FOOTINGS

S *8. WINGWALLS G

OTHER ABUTMENTS

*9. CAPS

*10. FOOTINGS

*11. WALLS G

*12. PILES

*13. WINGWALLS

P *14. ALIGNMENT (TIPING, TILTING,…) G

I *15. EROSION OR SCOUR G

E *16. SETTLEMENT

R *17. CAPS G PIER #2 CAP CHECKED FULL LENGTH

S *18. COLUMNS OR WALLS G

*19. FOOTINGS

*20. PILES G PIER 2: PILE 5 REPAIRED WITH STEEL SLEEVE, PILE 7 HAS

GRADER BLADE FOR PROTECTION, VERTICAL CHECKING

TYPICAL

*21. BRACING G

* Only these items are used in the determination of the overall condition rating for that category ie. Deck, superstructure, substructure. Other items should be rated and remarked on but NOT included in determining the overall category rating. Items enumerated using a C (ex C1) should be commented on but not rated. See the FHWA Coding Guide for further information as to what is included in condition rating.

Inspection Page 3 of 4

CONDITION CODES AND REMARKS (Continued)

CONDITION RATING REMARKS

61. CHANNEL AND CHANNEL PROTECTION 8

*1. CHANNEL SCOUR/EROSION G 18” SCOUR HOLE ADJACENT PIER #2, PILE #7. DEBRIS

COLLECTED ON PIER #2

*2. CHANNEL PROTECTION G

*3. VEGETATION G

*4. WATERWAY OBSTR./DRAFT G

*5. ADEQUACY OF OPENINGS G

C1. CLEAR HEIGHT 13’-6” MAXIMUM

APPROACH CONDITION: G

*1. SURFACING G ¾” ROAD MIX

*2. SHOULDER EMBANKMENT G

*3. ROADWAY EMBANKMENT G

*4. APPROACH SETTLEMENT G

APPRAISAL CODES and REMARKS

36. TRAFFIC SAFETY FEATURES: 0

*A. BRIDGE RAILING F TIMBER. NON-COMPLIANT

*B. RAIL TRANSITIONS

*C. APPROACH GUARDRAILS

*D. APPROACH RAIL ENDS

1. SIGNING

2. OBJECT MARKERS

72. APPROACH ROADWAY ALIGNMENT: 6

1. HORIZONTAL G TANGENT SECTION

2. VERTICAL P SHARP VERTICAL CREST CURVE APPROXIMATELY 70

YDS NE OF BRIDGE. POOR SIGHT DISTANCE

Bridge Appraisal Rating items may change as a result of this inspection. Use FHWA Coding Guide and

Regional Office direction for appraisal rating code determination.

67. STRUCTURAL EVALUATION: 6 68. DECK GEOMETRY: 2

71. WATERWAY ADEQUACY: 8 113. SCOUR CRITICAL BRIDGES:

STRUCTURE LIFE REMAINING SCOUR VULNERABILITY:

CONDITION RATING OF EACH MEMBER OR ELEMENT

NA -NOT APPLICABLE

NOB -APPLICABLE, BUT NO OBSERVED. (Give reason unless obvious)

G = GOOD -ELEMENT IN NEW OR GOOD CONDITION WITH NO REPAIRS NECESSARY.

F = FAIR -ELEMENT IS STILL PERFORMING THE FUNCTION FOR WHICH IT WAS

INTENDED BUT MAY NEED MAINTENANCE.

P = POOR -ELEMENT STILL PERFORMING THE FUNCTION FOR WHICH IT WAS INTENDED

BUT IS IN NEED OF REPAIRS.

C = CRITICAL -ELEMENT IS NOT PERFORMING THE FUNCTION FOR WHICH IT WAS INTENDED

Inspection Page 4 of 4

ITEM #

REFERENCE

ADDITIONAL REMARKS

59-C1 SPAN 1 – GIRDER 3: CHECKED @ MID-HEIGHT, HALF SPAN

SPAN 1 – GIRDER 4: SLIGHT DAMAGE AT DIAPHRAGM CONNECTION

SPAN 2 – GIRDER 7 CHECKED MID-HEIGHT, MID SPAN

SPAN 3 – GIRDER 2 SPLIT AT BEARING BOLT CONNECTION

SPAN 3 – GIRDER 3: CHECKED MID-HEIGHT, FULL SPAN

View looking southwest

View looking northeast – note impaired sight distance

View looking downstream

View looking upstream

View of wear on deck surface

View of damage to curb and rail at northwest corner

View of timber rail – note weather checking

View of split in end of Girder 2, Span 3

View of Pier 3 cap – note weather checking

View of Pier 3 – note debris accumulation

View of Abutment 2 piling – note poor bearing at pile cap

View of repair to pile on Pier 3

View of northeast wingwall – note broken column

LOAD RATING CALCULATIONS

PROJECT: MAFB TIMBER BRIDGE RATING; O-11 BRIDGE

JOB NO. 08-099

BY: DATE:

CHECKED: DATE:

Stringer: Flexure Stringer: Shear Fb 1700 psi Fv 145 psi

DF 0.466 Distribution Factor Area 144 in2

Mavail 51.7 ft-k Vavail 20.0 kips Inventory

Vavail 26.6 kips Operating

Mact Weight Inv Operat ft-k tons tons tons Vlu Vll fv Vact Weight Inven Operat

T3 72.8 25 38.1 50.7 kips kips psi kips tons tons tons

T3-S2 66.4 36 60.2 80.0 T3 11.3 6.02 62.7 9.03 25 55.4 73.6

T3-3 60.0 40 74.0 98.4 T3-S2 10.6 5.65 58.9 8.48 36 85.0 113

T-E 93.5 73.25 86.9 116 T3-3 9.33 4.97 51.8 7.46 40 107 143

T-E 14.0 7.46 77.7 11.19 73 130 174

Deck: Flexure Deck: Shear s 2.17 ft Max Deck Span clear dist 1.83 ft b 1.67 ft Tire Width b 1.67 ft Tire Width a 0.42 ft AISC 13th Ed. Table 3-23 Case 4 Area 72 in2

Mavail 5.7 ft-k Inventory Vavail 7.8 kips Inventory

Mavail 7.6 ft-k Operating Vavail 10.3 kips Operating wl^2/8

Wheel w R1 Mact Mact Weight Inven Operat Wheel w Rmax Vx fv Vact Weight Inven Operat kips klf kips ft-k ft-k tons tons tons kips klf kips kips psi kips tons tons tons

T3 8.5 5.10 4.250 3.56 3.00 25 47.5 63.3 T3 8.5 5.10 4.629 3.59 74.8 5.39 25 36.1 48

T3-S2 7.75 4.65 3.875 3.24 2.74 36 75.0 100.0 T3-S2 7.75 4.65 4.221 3.27 68.1 4.91 36 57 76

T3-3 8 4.80 4.000 3.35 2.83 40 80.7 107.6 T3-3 8 4.80 4.357 3.38 70.4 5.07 40 61 82

T-E 8.75 5.25 4.375 3.66 3.09 73 134.7 179.5 T-E 8.75 5.25 4.765 3.69 76.9 5.54 73 103 136

SAFE LOAD CAPACITIES (Tons)

Flexure Shear Flexure Shear Flexure Shear Flexure Shear

T3 38.1 55.4 47.5 36.1 50.7 73.6 63.3 48.0

T3-S2 60.2 85.0 75.0 57.1 80.0 113.0 100.0 75.9

T3-3 74.0 107.3 80.7 61.4 98.4 142.7 107.6 81.6

T-E 86.9 130.5 134.7 102.6 115.6 173.5 179.5 136.5

Timber Bridge Rating = 36.0 Tons

DeckStringer

Inventory Operating

Stringer Deck

AISC Eq 5.

BDM

AISC Eq 4.

7/31/2008

J:\2008\08-099\STRUCTURAL\Load Rating\O11 Bridge_final revision.xlsx Page 1 of 1

MISC. INFORMATION

Kick-Off Meeting

BRIDGE INSPECTIONS AND LOAD RATING FOR A-6 & O-11 BRIDGES

Malmstrom Air Force Base

Contract No. FA 4626-08-P-0019

AGENDA:

Project Overview

Project involves the formal NBIS inspection and load capacity rating of 2 bridges in north-central Montana. Deliverables include an inspection report for each bridge and a load capacity report for each bridge. Work will be completed in compliance with the Statement of Work and the Engineering Technical Letter 07-5; Bridge Inspections.

Individuals assigned to Project Tasks

Project Manager……………………. Neil Curry, P.E. (TD&H)

Bridge Inspection Leader…………...Bill Lloyd, P.E. (Great West Engineering)

Load Rating…………………………Neil Curry, P.E. (TD&H)

Brian May, P.E. (TD&H)

Garrett Drake, EI (TD&H)

Load Capacity Report ………………Neil Curry, P.E. (TD&H)

Garrett Drake, EI (TD&H)

Bill Lloyd, P.E. is a certified NBIS bridge inspector meeting the qualifications as listed in the

Statement of Work section 5.1 Qualifications of Personnel IAW 23 CFR § 650.309.

Project Schedule

Kick-Off Meeting………………….. July 7 th

, 9:00 am, at TD&H Office

On-Site Bridge Inspections………… July 8 th

, July 9 th

Load Rating Completion…………… July 25

Load Capacity Report Completion and Mailing to MAFB ………August 6

(Required Delivery Date…………….August 9

, 2008)

MEETING MINUTES:

• Meeting was held at the TD&H office on July 7 th at 9:00 am, and was attended by Mr.

Mike Miner with Missile Engineering, and Neil Curry with TD&H.

• Discussion of project schedule. Mr. Miner was made aware that our on-site inspections would be occurring July 8 th and possibly extending into July 9 th

. Final delivery date was discussed, as well as its occurrence on a Saturday. TD&H will strive for completion prior to the Saturday date.

• Water level at the A-6 bridge (Belt Creek) was discussed. It is felt that the inspection can take place at the current water levels, but the inspector will need to determine if full inspection can occur once he views the current water runoff.

• Mr. Miner delivered additional information including: A-6 bridge re-deck information, Military Truck loading information, and the O-11 bridge ID number (for obtaining previous inspection information).