Appraising the Existing Structure

Use the following procedure to determine the structural adequacy and condition of the existing structure:
  • Perform a load rating
    in accordance with the Bridge Inspection Manual for all structures in Fair or Good condition or if the bridge plans indicate a design less than HL-93, and provide a signed and sealed copy of the load rating to the District to be added to the Bridge Inspection Management System
    . At a minimum, the bridge must
    have a Rating Factor of 1.0 at the Operating Rating level for Specialized Hauling Vehicles, Emergency Vehicles, Design load of HS-20 or HL-93 design load, and any other truck loads added to the TxDOT Bridge Inspection Manual,
    and must have condition ratings as follows:
    • Item 58 (Deck)
      –
       Rating greater than or equal to 4
    • Item 59 (Superstructure)
      –
       Rating greater than or equal to 5
    • Item 60 (Substructure)
      –
       Rating greater than or equal to 5
    • Item 62 (Bridge-class Culvert)
      –
       Rating greater than or equal to 5
      Do not widen and/or rehabilitate a bridge if load posting would still be required after work is completed, except for the historically significant bridges discussed later in this chapter.
  • Perform a field assessment. The field assessment must be performed by a person who has successfully completed the bridge inspection training.
  • Submit the field assessment
    report, after it has been signed and sealed by a registered professional engineer in the State of Texas,
     to the Bridge Division project manager. The Bridge Division Field Operations Section Director will also consider the following factors in determining whether to rehabilitate or replace a structure:
    • Load Rating
    • Condition of the bridge as determined by the
      Field Assessment
    • Type of structure
    • Intended use (average daily traffic, percent of truck traffic, location, etc.)
  • Updated hydrologic and hydraulic analyses, including a scour analysis, are required for all bridge widening, bridge replacement, and roadway profile modifications that may adversely affect the flood plain, even if no structural modifications are necessary
Plan development can continue only if the Bridge Division concurs with the scope of work proposed in the field assessment form. These criteria apply to all bridge types, including bridgeclass culverts. Replace bridges with a load capacity that cannot be economically strengthened to
a Rating Factor of
 1.0 –
Operating Rating, for all load rating trucks in the TxDOT Bridge Inspection Manual