Attach 9_FSH 7709.56b, Chp 100 - Trail Bridge Operation.doc

7709.56b_100

WO AMENDMENT 7709.56b-2014-1

EFFECTIVE DATE: 11/24/2014

DURATION: This amendment is effective until superseded or removed.

7709.56b_100

FSH 7709.56b - Transportation Structures handbook

CHATPER 100 - TRAIL BRIDGE OPERATION

Table of Contents

2100.6 - References

3101 - INSPECTIONS

3101.1 - Scour Evaluation

3101.2 - Historic Bridge Evaluation and Inventory

3102 - QUALIFICATIONS OF INSPECTION PERSONNEL

4103 - TRAIL BRIDGE MANAGEMENT

4103.1 - Load Ratings

4103.2 - Weight Limit Posting, Closing, and Signing

5103.3 - Permanent Trail Bridge Files

5103.4 - Object Markers

5104 - PRIVATELY OWNED TRAIL BRIDGES AND OTHER ENGINEERED TRAIL STRUCTURES

6104.1 - Inspection, Posting, and Signing

6104.2 - Maintenance, Repair, and Replacement

6105 - EXHIBITS

6105.1 Trail Bridge Matrix

100.6 - References

1. American Association of Highway and Transportation Officials (AASHTO). “AASHTO LRFD Bridge Design Specifications.” Current Edition. The web address to order this publication is: https://bookstore.transportation.org/browse_bookstore.aspx.

2. AASHTO. “LRFD Guide Specification for the Design of Pedestrian Bridges”. Current Edition. The web address to order this publication is: https://bookstore.transportation.org/browse_bookstore.aspx.

3. American Association of State Highway and Transportation Officials (AASHTO). “Manual for Bridge Evaluation”. Current Edition. https://bookstore.transportation.org/browse_bookstore.aspx.

4. AASHTO. “Guide Specification for Strength Evaluation of Existing Steel and Concrete Bridges”. https://bookstore.transportation.org/browse_bookstore.aspx.

5. U.S. Department of Agriculture, Forest Service (USDA-FS). “Identifying and Preserving Historic Bridges”. 7100 Engineering. December 2000. Publication No. 0071-2854-MTDC. http://www.fs.fed.us/eng/php/eng_search.php?category=Program&srchword=05.

6. USDA-FS. “Sign and Poster Guidelines for the Forest Service”. Current Edition.

EM-7100-15. http://www.fs.fed.us/eng/techdev/sdtdc.htm.

7. USDA-FS. “Timber Bridges, Design, Construction, Inspection and Maintenance”.

EM-7100-8. August 1992. http://www.fpl.fs.fed.us/products/publications/.

8. USDA-FS. “Bridge Scour Evaluation: Screening, Analysis, and Countermeasures”. EM-7700. Transportation Systems. September 1998. Publication NO. 9877 1207-SDTDC. http://www.fs.fed.us/eng/techdev/sdtdc.htm.

9. USDA-FS. “Identifying and Preserving Historic Bridges”, EM-7100. December 2000. Publication No. 0071-2854-MTDC. http://www.fs.fed.us/eng/php/eng_search.php?category=Program&srchword=05.

10. U.S. Department of Transportation, Federal Highway Administration. “Bridge Inspector’s Reference Manual”. Current Edition. http://www.fhwa.dot.gov/bridge/elibrary.htm.

101 - INSPECTIONS

Inspect complex, major, and minor trail bridges and other engineered trail structures as specified below and in conformance with the trail bridge matrix in section 105.

Prepare and maintain inspection reports, records, and bridge inventories as prescribed in FSM 7737.3 and applicable regional guidance. Ensure that all required data are entered in Infra Trail Bridges Module.

101.1 - Scour Evaluation

Scour critical determinations and inspections are not required for trail bridges. However, trail bridges of significant value and importance or bridges whose failure could cause significant user safety or resource damage may be evaluated and inventoried for scour susceptibility per “Bridge Scour Evaluation: Screening, Analysis, and Countermeasures” (FSH 7709.56b, sec. 90.6).

101.2 - Historic Bridge Evaluation and Inventory

Record Historic Register status of bridges as outlined in USDA - Forest Service publication “Identifying and Preserving Historic Bridges”.

102 - QUALIFICATIONS OF INSPECTION PERSONNEL

1. Complex Trail Bridges. Inspectors shall be Bridge Inspection Team Leaders and shall be certified by the Regional Director of Engineering (FSM 7737.04c).

2. Major Trail Bridges. Inspectors shall be Bridge Inspection Team Leaders or shall successfully complete the National Trail Bridge Inspector Training and be certified by the Regional Director of Engineering (FSM 7737.04c).

3. Minor Trail Bridges. These bridges should be assessed by persons trained and qualified to perform Trail Assessment and Condition Surveys (TRACS).

4. Other Engineered Trail Structures. Inspector qualifications depend on the composition and complexity of the structure, the associated risk to the Inspector and the public, and the amount of any damage to the structure and should be determined by the Forest Supervisor in consultation with the Bridge Inspection Program Manager.

Review qualifications of any non-Forest Service Engineers before they perform complex trail bridge inspections and load ratings. Secure assistance from the Regional Bridge Engineer in that review.

103 - TRAIL BRIDGE MANAGEMENT

Record trail bridge inspection data in accordance with National and Regional guidance.

103.1 - Load Ratings

Load rate trail bridges and other engineered trail structures that have deteriorated or been damaged and that may no longer be structurally adequate to carry the intended users or snow load. A Certified Bridge Load Rating Engineer (FSM 7736.2) shall determine the safe load carrying capacity of these structures for their intended use.

New load ratings should conform to chapter 6 of AASHTO’s Manual for Bridge Evaluation. Load rate trail bridges using the Load and Resistance Factor Rating (LRFR) method, regardless of bridge material. Existing trail bridges with a load rating based on a method other than LRFR do not need to be rated with LRFR, unless a new load rating is required due to changed conditions. Use LRFR for all new load ratings. Refer to FSH 7709.56b, section 82.3 for guidance on load combinations.

103.2 - Weight Limit Posting, Closing, and Signing

The Forest Supervisor, in consultation with the Bridge Inspection Program Manager, is responsible for posting or closing trail bridges or other engineered trail structures that have been determined to have inadequate capacity to carry their intended loads. Post, close, and sign trail bridges or other engineered trail structures as follows:

1. Post weight restrictions in accordance with AASHTO’s Manual for Bridge Evaluation and the Sign and Poster Guidelines for the Forest Service (EM 7700-15).

2. Post the light vehicle design load for trail bridges that are at least 7 feet wide and that are accessible by motor vehicles larger than all-terrain vehicles.

3. Immediately close any trail bridge or other engineered trail structure when it is determined to be unsafe for current traffic and that traffic cannot be eliminated by posting weight restrictions or adding devices constraining use of the bridge.

4. In closing trail bridges and other engineered trail structures:

a. Install signs and barricades at the bridge or structure. Signs and devices must meet the requirements of EM-7100-15.

b. To the extent practicable, monitor closures to determine that signs and barricades are maintained in a satisfactory condition until they are no longer needed.

c. Consider the possibility of vandalism of signs and devices when evaluating closure methods. When practicable, use a method that is less likely to be affected by vandalism in areas with known vandalism problems.

d. When practicable, use physical barriers to prevent access.

e. Post appropriate notice of the closure at trailheads and trail junctions.

f. Issue an order under 36 CFR 261.55 when Forest Service enforcement of the closure is necessary (FSH 5309.11, ch. 32).

5. Do not rely on the prohibition against motor vehicle use on undesignated trails (36 CFR 261.13) as the sole means to prevent motor vehicle use on trail bridges and other engineered trail structures along undesignated trails. As appropriate, use the methods in FSH 7709.56b, section 103.2, paragraphs 1 through 3, for that purpose.

103.3 - Permanent Trail Bridge Files Maintain a permanent file for each complex and major trail bridge, and each other engineered trail structure (FSM 7723.1 and 7737.1). Permanent trail bridge files should be maintained at a single location determined by Regional guidance. Permanent bridge files should be readily available to the Trail Bridge Inspection Program Manager and at a minimum should include:

1. As-built plans;

2. Inspection reports, including management summaries and photographs;

3. Load rating calculations, if applicable; and

4. A record of maintenance, repairs, and modifications.

103.4 - Object Markers

Delineate all four corners of a trail bridge on trails designated for motor vehicle use with properly located object markers installed in compliance with the current edition of the Manual on Uniform Traffic Control Devices and EM 7100-15.

104 - PRIVATELY OWNED TRAIL BRIDGES AND OTHER ENGINEERED TRAIL STRUCTURES

Special-use authorizations for privately owned trail bridges and other engineered trail structures on NFS lands authorized by permit, term permit, lease, or easement (special-use authorizations) should include clauses for inspection, operation, and maintenance of these structures to adequately protect the public and National Forest System Lands and resources. The inspection, operation, and maintenance requirements within FSM 7737 and the guidance within this section are recommended for all trail structures designed and installed on NFS lands, regardless of ownership or jurisdiction.

Permit holders are responsible for compliance with these requirements and inspection, operation and maintenance costs for structures authorized by their permit.

104.1 - Inspection, Posting, and Signing Ensure that inspections are performed on complex and major trail bridges and other engineered trail structures (FSM 7737.05) and that condition assessments are performed on minor trail bridges.

Ensure that the inspection requirements, inspection intervals, and inspector qualifications included in this chapter are followed.

Ensure that a bridge inspection file is maintained that is available to the Forest Service upon request and that at a minimum includes:

1. A current inspection report.

2. Bridge design calculations and plans, if available.

3. Photographs of the bridge, approaches, elevations, the channel upstream and downstream, and any visible deficiencies in the structure.

104.2 - Maintenance, Repair, and Replacement

Ensure that the holder provides a copy of plans for routine maintenance and any proposed repairs or replacement to the Authorized Officer for review prior to commencing the work. Ensure that the operating plan addresses how and when maintenance, repairs, and replacement will be conducted. Ensure that the operating plan allows the Authorized Officer to require the holder to develop a design, plans, and specifications for this work and abide by construction standards established by the Bridge Engineer per FSH 7709.56b, section 86.

105 - EXHIBITS

105.1 Trail Bridge Matrix

The following matrix (ex. 01) provides a summary of the definitions, inspection requirements, and data storage protocols for Trail Bridges, Trail Structures, and other structures commonly associated with trails.

105.1 – Exhibit 01

Trail Bridge Matrix

Trail Bridge

A trail structure, including supports, erected over a depression or obstruction such as a body of water, a road, a trail, or a railroad that provides a continuous pathway and that has a deck for carrying traffic or other loads.

Trail bridges are divided into three categories for inspection purposes:

1. Complex trail bridges;

2. Major trail bridges; and

3. Minor trail bridges.

Infra Trail Bridges Module

Complex

Trail Bridge

1. Meets bridge inspection team leader requirements per the NBIS; and

2. Is certified by the Regional Director of Engineering.

Complex and Major Trail Bridge Inspection Form

105.1 – Exhibit 01--Continued

1. Has successfully completed the National Trail Bridge Inspection Training; and

2. Is certified by the Regional Director of Engineering.

or TRACS Form 60 months1 for complex and major trail bridges.

Refer to current agency protocols for minor trail bridges.

Infra Trail Bridge Module and

Infra Trails Module

105.1 – Exhibit 01--Continued

A more frequent inspection interval may be appropriate due to the complexity, age, condition, and use of the structure.

Main load carrying elements include the stringers or deck.

The clear span is measured between abutment faces, along the centerline of the trail.

Elevated boardwalk height is measured from the lowest adjacent ground surface to the top of the boardwalk deck.

Retaining wall height is measured from the lowest adjacent ground surface to the top of the retaining wall.