Reduced Inspection Interval
The following outlines TxDOT policy and requirements for risk-based inspection intervals outlined in 23 Code of Federal Regulations (CFR) 650.311 using Method 1 inspection interval determination for changing the interval of Underwater Inspections. The level of inspection for underwater inspections with decreased inspection intervals will be the same as that required for those scheduled on a 60-month interval.
Bridges meeting the criteria below require reduced interval inspection of not greater than 24 months per Method 1 provisions as amended below:
- Underwater Inspection Condition (Item B.C.15) ≤ 4 [Substructure Condition Rating (Item 60) ≤ 4]
- Channel Condition (Item B.C.09) ≤ 4 [Channel and Channel Protection Condition Rating (Item 61 ≤ 4]
- Channel Protection Condition (B.C.10) ≤ 4 [Channel and Channel Protection Condition Rating (Item 61) ≤ 4]
- Scour Condition Rating (Item B.C.11) ≤ 3 [Scour Critical Bridges (Item 113) ≤ 3]
The inspection interval may be assigned as either 12 or 24 months based on the severity and recent progression of the deficiency. The basis for assigning either a 12-month or a 24- month interval must be clearly documented in the inspection report.
Reducing a condition rating to a 3 or lower for Pier or Abutment Protection (NBI Item 111) due to a reduction in protection provided by the protection feature will be cause to perform special underwater inspections on an interval of 12 or 24 months. The interval assigned is based on the severity of the damage to the protection feature. The special underwater inspection will be limited to the pier or abutment protection and the substructure components adjacent to the damaged feature. The level of inspection for substructure components inspected will be the same as that for routine underwater inspections.