National Bridge Inventory Ann Shemaka Federal Highway Administration

National Bridge Inventory Ann Shemaka Federal Highway Administration Office of Bridge Technology

National Bridge Inventory n 23 USC 151 – National Bridge Inspection Program (NBIP) n n Requires each State to maintain current inventory data for all highway bridges 23 USC 144 – Highway Bridge Program (HBP) n n Inventory all highway bridges on public roads Classify according to serviceability, safety and essentiality for public use (Sufficiency Rating) Assign priority for replacement or rehabilitation based on that classification Determine cost of replacement or rehabilitation

National Bridge Inventory n 23 CFR 650 C – National Bridge Inspection Standards (NBIS) n n Each State or Federal agency must prepare and maintain an inventory of all bridges subject to the NBIS. Sets the Recording and Coding Guide for the Structure Inventory and Appraisal of the Nation’s Bridges (December 1995) together with subsequent interim changes or the most recent version as the guiding document.

National Bridge Inventory n The Coding Guide Sets: n n n The minimum data elements to be inspected, (States collect more data elements on their bridges including element level data such as details on joints, bearings, connection) How they are to be recorded, and The format in which they are to be reported to the FHWA

Coding Guide n n n There are 94 data items collected Items are collected and stored in metric values Items are broken down into item groupings

Coding Guide Item Groupings n Identification Data n n Structure Type and Material Type n n Examples: facility carried, location, latitude and longitude Examples: structure type of main and approach structures, material of main and approach structures, wearing surface, and deck protective system Age and Service n Examples: year built, number of lanes, average daily traffic

Coding Guide Item Groupings n Geometric Data n n Navigational Data n n Examples: length of bridge, width of bridge, horizontal and vertical clearances Examples: pier protection and navigational clearances Classification Data n Examples: National Highway System designation, toll road, parallel structure

Coding Guide Item Groupings n Condition Data n n n Examples: Deck, Superstructure and Substructure Load Rating and Posting Data Appraisal Items n n n Calculated geometric data evaluations for functionally obsolescence Safety features such as guardrails & transitions Scour criticality

Coding Guide Item Groupings n Inspection Data n n Routine inspection date and interval Special inspections requires such as fracture critical and underwater

Status Rating n n Upon incorporation of the data into the National database a status is also assigned. There are 4 Status types n n Structurally Deficient Functionally Obsolete Not Deficient Not Applicable

Status Rating Structurally Deficient n A bridge is considered structurally deficient if significant load-carrying elements are found to be in poor condition or the waterway adequacy is insufficient. This does not imply the bridge is unsafe rather in need of repair. If a bridge is unsafe it is closed.

Status Rating Functionally Obsolete n Functional Obsolescence is a function of the geometrics of the bridge in relation to the geometrics required by current design standards.

Status Rating Not Deficient and Not Applicable n n A bridge is assigned a condition of not deficient if it is not Structurally Deficient or Functionally Obsolete. A status of Not Applicable is assigned if the bridge is a non highway bridge. (Certain non highway structures are reported even through they are not required to be).

Sufficiency Rating n n Upon incorporation into the National database, an overall Sufficiency Rating is calculated for each bridge. A value from 100 down to 0 is assigned n n 100 is best and 0 is worst Used to distribute HBP funds. n n Federal-aid replacement (SR 0 -49. 9) Federal-aid rehabilitation (SR 50 -80) Non Federal-aid replacement (SR 0 -49. 9) Non Federal-aid rehabilitation (SR 50 -80)

Sufficiency Rating n There are three main components of the calculation and these are defined in USC n n Structural Adequacy and Safety (55%) Serviceability and Functional Obsolescence (30%) Essentiality for Public Use (15%) Above components are set in USC the percentages are not. Assigned by FHWA

Sufficiency Rating Structural Adequacy & Safety n n The condition of the deck, superstructure and substructure as well the inventory rating are evaluated. Deductions are made for poor ratings.

Sufficiency Rating Serviceability & Functional Obsolescence n n Items such as the lanes on the structure, ADT, roadway width, and the calculated geometric items are evaluated. Deductions are made for inadequate conditions.

Sufficiency Rating Essentiality for Public Use n n Detour length, ADT and the highway designation are evaluated. Deductions are made for inadequate conditions.

Uses of a National Database n n Monitor compliance with the NBIS Use as a source for distribution of funds for the Highway Bridge Program Reporting to Congress and others on the Status of the Nation’s Bridges National security concerns

National Bridge Inventory n n Recognized need to update existing Coding Guide Draft Specification Development Team n n n FHWA, HQ, and Division Offices Federal Lands Office who represent the Federal Agencies Objectives n n n Clean up wording Make guide easier to use Propose value added changes

National Bridge Inventory n n Form FHWA Review Team Identify significant problems, unclear language, additional items needed and items no longer needed Develop Stakeholder review package Distribute review package

National Bridge Inventory n n Evaluate feedback from Stakeholders Prepare final Specification Make presentation at AASHTO T-18 Determine other needed actions n n NBI database system changes OMB clearances Training Develop implementation plan