H-T AE Load Rating

Statement of Work 2026 H-T AE Load Rating Task Order SCHEDULE OF ITEMS: Item Description Price Quantity Total 1 Bridge Load Rating $ 5 $ 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. 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. Provide results under Strength I & II and Service III as required. Service III shall only be reported and not the basis for the rating. Load Combinations: Strength I and Service II for Steel Strength I for Concrete Strength I and Service III for Prestressed Concrete Resistance Factors – per engineer’s judgment based on inspection reports. System Factor – per engineer’s judgment. Complete load ratings for SU4 through SU7 trucks when NRL RF is less than 1. Calculate Safe Load Capacity if RF is greater than 1. Calculate Safe Posting Load if RF is less than 1. For Shear in concrete bridges, referenced by MBE 6A.5.8, use simplified analysis if bridge inspections show no signs of shear distress. 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. 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: 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. Provide a summary of ratings and list the lowest rating for each axle(s), truck or vehicle being rated. The sheet …