Section 4: Routine Inspections

Overview

Routine inspections are those regularly scheduled, performed, and recorded in accordance with all the procedures described in Chapter 8, Section 3 of this manual, Inspection Documentation and the Bridge Record, the TxDOT Coding Guide, and Specification for the National Bridge Inventory (SNBI). Conduct these inspections every twenty-four months for most bridges, and every forty-eight months for qualifying concrete culverts and span bridges. Some bridges need reduced inspection intervals when conditions warrant. Criteria for reduced and extended inspection intervals based on the requirements for risk-based inspection intervals outlined in 23 CFR 650.311 utilizing Method 1 inspection interval determination, which includes 48-month inspections of concrete box culverts, are provided later in this section. With the transition from the Coding Guide to the SNBI in accordance with 23 CFR 650.311, the collection and use of certain SNBI data is required to establish inspection intervals and to update and implement the reduced inspection interval policies by June 6, 2024. Prior to SNBI data collection TxDOT will utilize equivalent criteria per the Coding Guide to determine the reduced interval inspection.
As outlined in Section 8 of this Chapter, include evidence of visual inspection and descriptions of members qualifying as Internally Redundant Members (IRM) and System Redundant Members (SRM) to confirm that they are still in a condition eligible for inclusion as IRM and SRM.

Inspection Equipment

The equipment needed for routine bridge inspections usually includes the following:
  • Cleaning tools including wire brushes, scraping tools, and whisk broom
  • Inspection tools including pocketknife, ice pick, increment borer, and sounding hammer
  • Visual aid tools including binoculars, flashlight, magnifying glass, dye penetrant, and a mirror
  • Basic measuring equipment including thermometer, crack comparator, center punch, simple surveying equipment, rulers, tape measures, and weighted reel tapes
  • Recording materials such as appropriate forms, field books, cameras, and electronic tablets
  • Access equipment including ladders, watercraft, waders, ropes, etc.
  • Safety equipment such as first-aid kits, mobile phone, emergency numbers, sunblock, etc.
  • Miscellaneous equipment should include C-clamps, penetrating oil, insect repellant, wasp and hornet killer, stakes, flagging, and markers.
A more complete description of the usual inspection equipment can be found in Chapter 2 Section 4 of the
Bridge Inspector's Reference Manual.
Some inspections may significantly interfere with normal traffic movement and could endanger the bridge inspectors and the traveling public. Coordinate these inspections with district personnel to ensure that appropriate traffic control measures are taken.
The underside of some bridges cannot be reached for inspection by conventional ladders. Binoculars and other visual aids can be implemented. If a problem is discovered that is out of reach for verification by routine access methods, communicate such limitations with the district and the Bridge Division.

Reduced Inspection Interval

Chapter 6 of this manual includes a load rating flow chart for concrete bridges without plans. This flow chart requires that concrete structures which have no plans showing reinforcing details, are new to the Inventory, and are without structural distress will be in inspected at either 12- or 24-month intervals. Those bridges which have not been carrying unrestricted traffic for at least 4 years will receive inspections every 12 months. Additional clarifications are made for those bridges exhibiting distress or those which do not follow other geometric characteristics. Chapter 6 also includes flow charts for load posting guidelines that includes TxDOT policy on inspection interval for on-system and off-system bridges. The reduced inspection interval for routine inspections is summarized in the table below. The level of inspection for routine inspections on structures with reduced inspection interval will be the same as that required for those scheduled on a 24-month interval.
Bridges meeting any of the criteria below require reduced inspection interval of 12 months:
  • Concrete Bridge without plans, without structural distress, and structure age < 4 Years
Bridges meeting the criteria below require reduced inspection interval of 6 months:
  • Off-System Structure with IR < HS 3, OR > HS 3, and posted based on inventory rating
  • On-System Structure with IR < HS 3, OR > HS 3, and posted based on inventory rating
Bridges meeting the criteria below require reduced interval inspection of ≤ 12 months per Method 1 provisions:
  • Deck Condition Rating (Item B.C.01) ≤ 3 [Deck Condition Rating (Item 58) ≤ 3]
  • Superstructure Condition Rating (Item B.C.02) ≤ 3 [Superstructure Condition Rating (Item 59) ≤ 3]
  • Substructure Condition Rating (Item B.C.03) ≤ 3 [Substructure Condition Rating (Item 60) ≤ 3]
  • Culvert Condition Rating (Item B.C.04) ≤ 3 [Culvert Condition Rating (Item 62) ≤ 3]
  • Scour Condition Rating (Item B.C.11) ≤ 3 [Scour Critical Bridges (Item 113) ≤ 3]

Extended Inspection Interval

Certain bridges meeting all the criteria for extended intervals of 23 C.F.R. § 650.311 - Inspection interval may be inspected at intervals not to exceed 48 months. TxDOT’s criteria for extended intervals adds an additional requirement which disqualifies bridges containing timber elements in the load path (deck superstructure, or substructure). Bridges that qualify for extended interval inspections will have the same level of inspection for routine inspection as structures scheduled on a 24-month interval. The criteria for application of a 48 month inspection interval is:
  • Deck Condition Rating (Item B.C.01) ≥ 6 [Deck Condition Rating (Item 58) ≥ 6]
  • Superstructure Condition Rating (Item B.C.02) ≥ 6 [Superstructure Condition Rating (Item 59) ≥ 6]
  • Substructure Condition Rating (Item B.C.03) ≥ 6 [Substructure Condition Rating (Item 60) ≥ 6]
  • Culvert Condition Rating (Item B.C.04) ≥ 6 [Culvert Condition Rating (Item 62) ≥ 6]
  • Channel Condition (Item B.C.09) ≥ 6 [Channel and Channel Protection Condition Rating (Item 61) ≥ 6]
  • Channel Protection Condition (Item B.C.10) ≥ 6 [Channel and Channel Protection Condition Rating (Item 61) ≥ 6]
  • Inventory Load Rating Factor (Item B.LR.05) ≥ 1.0 [Inventory Rating (Item 66) ≥ 1.0, when expressed as a rating factor, or Item 66.2 ≥ 36 if expressed as tons]
  • Routine Permit Loads (Item B.LR.08) = A or N. [Structure Open/Posted/Closed Status (Item 41) = A - Open. Note that if a structure is coded with Item 41 = A, it is unrestricted for Routine Permit Loads in Texas.]
  • Fatigue Details (Item B.IR.02) = N
  • Highway Minimum Vertical Clearance (Item B.H.13) ≥ 14.0 [Minimum Vertical Clearance Over Bridge Roadway and Minimum Vertical Underclearance (Items 53 and 54B) ≥ 0420 (i.e., 4.20 m / 14.0 ft)]
  • Span Material (Item B.SP.04) = C01-C05 or S01- S05 [Main and Approach Span Structure Material (Items 43A and 44A) = 2, 3, 4, or 5]
  • Span Type (Item B.SP.06) = A01, B02-B03, F01- F02, G01-G08, P01-P02, or S01-S02 [Main and Approach Span Structure Construction (Items 43B and 44B) = 01, 02, or 05] *See below for notes
  • Scour Vulnerability (Item B.AP.03) = A or B [Scour Critical Bridges (Item 113) = 5 or 8]
  • Scour Condition Rating (Item B.C.11) ≥ 6
The following TxDOT SI&A Coding qualifies for extended inspection intervals. *Member_Type_Main_Span (TXDOT_SI&A_NBI_043.1.3), Member_Type_Major_Span (TXDOT_SI&A_NBI_043.2.3), and Member_Type_Minor_Span TXDOT_SI&A_NBI_043.3.3) must be the following:
  • 01-Weathering Steel (WS) I-Beam
  • 02-WS Plate Girder - Multiple
  • 03-WS Plate Girder, Var. Depth - Multiple
  • 05-WS Box Girder - Multiple
  • 11-Steel I-Beam
  • 12-Plate Girder - Multiple
  • 13-Plate Girder, Var. Depth - Multiple
  • 15-Steel Box Girder - Multiple
  • 21-Concrete Girder - Tee Beam
  • 22-Concrete Girder, Var. Depth - Tee Beam
  • 23-Concrete Box Girder - Multiple
  • 26-Concrete Flat Slab
  • 27-Concrete Slab - Variable Depth
  • 31-PS Concrete Girder - Multiple
  • 33-PS Concrete Box Girder - Multiple
  • 36-PS Concrete Slab - Full Depth
  • 37-PS Concrete Slab - Partial Depth
*Culvert_Span_Type (TXDOT_SI&A_NBI_043.4.1) must be one of the following:
  • 1-Single Box
  • 2-Multiple Box
  • 3-Single Pipe
  • 4-Multiple Pipe
*Culvert_Main_Member_Type (TXDOT_SI&A_NBI_043.4.2 must be one of the following:
  • 1-Steel
  • 3-Concrete
  • 7-Precast/Prestressed
Before for any new, rehabilitated, or structurally modified bridge can be eligible for inspection intervals greater than 24 months, it must receive an initial inspection, be in service for 24 months and receive its next routine inspection.

Bridge Inspection Interval Tolerance

Bridges are to be inspected in the month due unless otherwise approved by the State Bridge Inspection Program Manager.
To accommodate situations such as severe weather, bridge inspection safety, schedule optimization or other unique situations that may cause an adjustment to the scheduled inspection date, 23 CFR 650.311 has set requirements for bridge inspection interval tolerances:
  • The acceptable tolerance for inspection of bridges on intervals of less than 24 months is two months beyond the month in which the inspection was due (i.e., for inspection interval of 12 months, acceptable to inspect in the 14th month)
  • The acceptable tolerance for inspection of bridges on intervals of 24 months or greater is three months beyond the month in which the inspection was due (i.e., 27th month)
  • Exceptions to the inspection tolerance due to rare circumstances must be approved by FHWA in advance of the inspection due date plus the tolerance mentioned above providing adequate time for review and approval.
Chapter 8, Section 3 – Inspection Documentation and the Bridge Record provides information for the Delayed Inspection Memo that is required if an inspection was performed past the month the inspection was due. When inspections are delayed for reasons other than schedule optimization, the next inspection is to be scheduled on the month the inspection was originally scheduled to occur to return the inspection to the original scheduled month.

Discovery of Flammable Materials Below Bridges

Bridge Inspectors are to report flammable material stored or accumulated under bridges as a Priority Level 2 Follow-up Action Recommendation. FHWA has directed states to treat the discovery of materials, including flammable, explosive, or hazardous materials, stored in the right of way (ROW) underneath bridges that are of concern, as in inspection critical finding requiring immediate follow-up action. There will be a need for use of judgement as to the risk to the bridge. Things to consider are the volume of the debris, the type of debris, the proximity of the material to the substructure and/or the bottom of the superstructure, etc. When the conditions are such that an apparent immediate threat to public safety exists, inspectors are to report such findings as an inspection critical finding.