What information must be included in a bridge database?
It includes identification information, bridge types and specifications, operational conditions, bridge data including geometric data and functional description, and inspection data. Any bridge more than 20 feet (6 meters) long used for vehicular traffic is included.
How are bridges rated?
They are rated on a scale of zero to nine—with nine meaning the bridge is in “excellent” condition. A bridge is classified as structurally deficient and in need of repair if the rating on a key structural element is four or below.
What does NBI stand for in bridges?
National Bridge Inventory (NBI)
How is NBI calculated?
The Index is a modified market capitalization-weighted index. NBI employs a two-stage weight adjustment scheme. Index Securities’ initial weights are determined by dividing each Index Security’s market capitalization by the aggregate market capitalization of all Index Securities.
What makes a bridge functionally obsolete?
Functionally obsolete bridges are those that do not have adequate lane widths, shoulder widths, or vertical clearances to serve current traffic demand, or those that may be occasionally flooded. A functionally obsolete bridge is similar to an older house.
What state has the most bridges?
Texas
Texas holds the title for the state with the most bridges.
Do bridges have numbers?
Structure numbering covers bridges, culverts, some lineside structures and occasionally buildings. Structures are numbered uniquely on each line, which can lead to some structures carrying two numbers when they carry two lines. Structures built in between existing structures carry the suffixes A, B, etc.
What is the most important part of a bridge?
Foundation: The foundation (or base) of a bridge is the element that connects the structure to the earth and transfers loads from it to the ground below. Girder: A girder is the main horizontal support beam on a bridge. It supports the smaller beams.
What is the function of bridge structure?
A bridge is a structure built to span a physical obstacle (such as a body of water, valley, road, or rail) without blocking the way underneath. It is constructed for the purpose of providing passage over the obstacle, which is usually something that is otherwise difficult or impossible to cross.
What is the lifespan of bridges?
The average bridge in the U.S. is 43 years old. Most of the country’s bridges were designed for a lifespan of 50 years, so an increasing number of bridges will soon need major rehabilitation or retirement.