What is the purpose of bridge inspection?
1.2 Purpose of bridge inspection 1. To know whether the bridge is structurally safe, and to decide the course of action to make it safe. 2. To identify actual and potential sources of trouble at the earliest possible stage.
What is a principal bridge inspection?
Principal Inspections. A Principal Inspection requires close examination of all inspectable parts of the bridge within touching distance. The in-depth survey includes visual inspections as well as specialist techniques such as hammer tap surveys of concrete, or corrosion measurement.
What qualifies a bridge?
The NBI can classify bridges as “Structurally Deficient”, which means that the condition of the bridge includes a significant defect, often meaning that speed or weight limits must be put on the bridge to ensure safety; a rating of 4 or lower on any of items 58, 59, 60, or 62 (Deck, Superstructure, Substructure, and …
How safe are train bridges?
Quick Facts. America’s railroad bridges are safe. It has been almost 60 years since a fatality occurred due to the structural failure of a railroad bridge on any U.S. railroad. In fact, railroad bridges are among the safest segments of the nation’s rail infrastructure.
What are the most common materials used in bridge construction?
Bridge materials. Some of the main materials found on a bridge are steel, concrete, stone and asphalt. Other materials include iron, timber, aluminum, rubber and other joint materials.
How often are bridges inspected?
every two years
The “routine” inspection is the most common type of inspection performed and is generally required every two years. The purpose of “routine” inspections is to determine the physical and functional condition of a bridge on a regularly scheduled basis.
How do you inspect a bridge?
6 Methods for Inspecting Bridge Damage and Deterioration
- Acoustical Techniques. Method: This is a non-destructive technique which is performed using a chain drag or hammer to identify changes in sound pitch.
- Infrared/Thermal Imaging Inspection.
- Coring and Chipping.
- Ground-Penetrating Radar (GPR)
How much does it cost to replace a BNSF bridge?
This new, $15 million bridge is one of several current replacement projects under BNSF’s Heavy Bridge Program. Under this program, large bridge structures, such as those spanning large waterways, are identified and replaced based on their condition as they near the end of their useful life.
Where is the BNSF bridge in Washington State?
That’s what happened when BNSF floated in a new bridge to replace a century-old steel truss bridge over Drano Lake in Washington. The lake is fed by the Columbia River and in a remote area, with the bridge on BNSF’s line running east from Vancouver – an important route for grain export.
When did the first train cross the new bridge?
In 18 days the project was completed, with the first train crossing the new bridge Sept. 14. Here’s a look at how we did it, safely and on schedule: