A04 SOW 1175739.docx

2026 R4 AE Load Rating Task Order 3 of 5 Statement of Work

2026 H-T AE Load Rating Task Order

SCHEDULE OF ITEMS:

General: The work consists of load rating 5 Forest Service road bridges in Nevada. Plans are not available for any of the bridges. A list of the structures is attached.

Rating Specifications: Bridge load ratings shall be completed in accordance with current edition of AASHTO Manual for Bridge Evaluation (MBE), using Load and Resistance Factor Rating methodology outlined in Chapter 6, Part A. The following outlines additional Load rating requirements.

1. Load rating vehicles shall include:

· Design Load: HL-93 (Inventory = LF 1.75 and Operating = LF 1.35)

· AASHTO Legal Loads – Type 3, 3S2, 3-3. LF = 1.3

· Emergency Vehicles LF=1.3

· Notional Rating Load. LF = 1.3

· Permit Load - 5 axle, 50 ton, 57 foot low boy. LF = 1.1. See below.

2. Provide results under Strength I & II and Service III as required. Service III shall only be reported and not the basis for the rating.

3. Resistance Factors – per engineer’s judgment based on inspection reports.

4. System Factor – per engineer’s judgment.

5. Complete load ratings for SU4 through SU7 trucks when NRL RF is less than 1.

6. Calculate Safe Load Capacity if RF is greater than 1. Calculate Safe Posting Load if RF is less than 1.

7. For Shear in concrete bridges, referenced by MBE 6A.5.8, use simplified analysis if bridge inspections show no signs of shear distress.

8. Stringer-supported concrete deck slabs and metal decks that are carrying normal traffic satisfactorily need not be routinely evaluated for load capacity when they show signs of satisfactory performance.

9. Use methodology in MBE chapter 6A to determine strength properties of existing members. No concrete coring or steel coupon test is required.

Nondestructive Testing (NDT) Evaluation:

The bridges will require field evaluation prior to their load ratings.

The Ground Penetrating Radar (GPR) should determine rebar locations, spacing, cover and orientation; slab thicknesses; and pre-stress strand locations, spacing, cover, and orientation. GPR should be used on top and bottom of slabs, sides of concrete beam webs and bottom flanges. Typical rebar and strand size, orientation and depth should be confirmed by drilling or chipping a small hole at the strand or rebar. Small holes confirming rebar and strands should be kept to a minimum. After the embedded steel information is verified, coat the steel with zinc rich paint and grout the hole full and trowel flush with existing concrete. The high strength, non-shrink grout used should be appropriate for overhead concrete repair use. Indicate in the field the locations of testing, prior to the evaluation. Additional or different bridge element areas may be selected as required to collect pertinent information for the load rating calculations. Specific areas should be marked with duct tape, marker or paint. An average of several calibrated rebound hammer results may be used to determine concrete compressive strength. Field personnel should have a ladder, shovel and broom, or other cleaning tools if additional cleaning is required.

Load Rating Program and Analysis:

All bridges shall be rated using the current version of BRASS Girder, Leap Bridge Concrete, Brass-Culvert, Brass-Truss, Brass-Dist, RISA, LARS, AASHTO Bridge Rating Software (BRS), Slab, TBAR, Plank, and Timber. BRASS software is preferred for steel and concrete bridges. TBAR is preferred for timber bridges, unless the timber girders require a more specific girder analysis (i.e., alternating glued-laminated and rough sawn girders or damaged girders). Each bridge rating shall be summarized on a Load Rating Summary Sheet with some of the assumptions listed at the bottom of the sheet in the notes. Ratings shall determine the rating factors for each rating vehicle and the safe load capacity tonnage for each legal load vehicle. The ratings shall cover all rated components, i.e., damaged girder, interior girder, exterior girder, deck, stringer, floor beam, truss, gusset plate, etc.

Bridge load ratings shall be completed under the direction of and checked by a Professional Engineer registered in the State where the bridge is located. Load rating engineers shall have access to or be a qualified NBIS Bridge Inspection Team Leader and a Registered Professional Engineer with a minimum of 3 years’ bridge design experience. The consultant shall notify the Forest Service as soon as possible if a rating would require a new or changed posting limit, if a rating factor is less than 0.3.

The consultant will be given electronic or hard copies of the documents listed below.

The consultant shall use the following file naming convention:

“YYYYMMDD_BridgeNumber_LoadRating”

Deliverables:

Completion of the work in 2026 is preferred. However, the field data collection and load rating may be completed in 2027 if necessary. The consultant shall submit a draft and final load rating report. The draft report shall be uploaded to the Pinyon External folder no later than July 31, 2027. The Forest Service shall review the draft calculations within 14 days upon receipt. The final submittal shall be uploaded into the Pinyon External folder by August 31, 2027.

The final submittal shall include all load rating documents in original and PDF formats.

Bridge Load Rating Report Guidelines

The individual reports shall contain, as a minimum, the following information:

a. Information to clearly identify the bridge: the bridge name and number and the Forest and Ranger District in which the bridge is located. Latitude and longitude may be provided if desired.

b. Provide a summary of ratings and list the lowest rating for each axle(s), truck or vehicle being rated. The sheet shall contain the name, date(s), seal, and signature of the Engineer responsible for the bridge rating work and the name of the Engineer checking the bridge rating. Attached is an example summary sheet.

c. Statement of Report Basis - If the bridge is being rated on the basis of assumed new condition before or shortly after construction, this should be stated. If the bridge is being rated on the basis of an inspection report, this should be stated. Such a statement should also refer to the date, bridge inspector, and organization that prepared the inspection report. Any other information used as a basis for the rating shall also be stated along with the date, the individual, and organization that prepared it. Include the inspection report if available.

d. Calculations supporting the ratings, including assumptions, sketches, explanatory notes, program input and output files, Mathcad sheets, and Excel sheets.

e. List all assumptions for concrete strength and steel strength. Also, list any directions provided by the Regional Bridge Engineer.

f. Any plans, shop drawings, fabricator calculations, and any fabricator or construction documents used in the rating, if available.

Government Furnished Items:

1. Most recent bridge inspection reports, if available.

2. Previous ratings, drawings, measurements, or other documents with information that can be used for the rating, if available.

3. Example summary sheet.

Schedule:

The submittals are due within the timeframe stated in the deliverables section.

Quality Control/Quality Assurance:

The consultant is responsible for the quality and accuracy of their work.

Forest Service Review:

The Forest Service review of the work at and after the final submittal shall be for overall conformance with the project scope of work, inspection/report criteria, and generally accepted practices of the inspection and report preparation.

Contracting Officer’s Representative Tyrone Stone 208-201-0309 tyrone.stone@usda.gov

(EXAMPLE) SUMMARY OF RATING

(Rating Factors)

HL- 93 Operating __________ __________ __________ __________ __________

Type 3 Truck __________ __________ __________ __________ __________

Type 3S2 Truck __________ __________ __________ __________ __________

Type 3-3 Truck __________ __________ __________ __________ __________

NRL __________ __________ __________ __________ __________

Permit Load __________ __________ __________ __________ __________

- 5 axle, 50 ton, 57 foot lowboy XX Truck __________ __________ __________ __________ __________

XX Truck __________ __________ __________ __________ __________

(SLC) = Safe Load Capacity (SPL) = Safe Posting Load Notes or Comments:

Load Rating Performed by:

Initials/Date:

Load Rating Checked by:

Initials/Date:

Statement of Report Basis:

Bridge Inspector:

Organization:

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