By Claudia Lawyer – Associated Press
A 50-year-old bridge that collapsed in Pittsburgh was considered weak in a recent inspection report, but transport officials and engineers warned it could endanger thousands of other American bridges of the same name.
Investigators at the National Transportation Safety Board and the Federal Highway Administration are investigating the cause of the collapse of Forbes Avenue early Friday.
President Joe Biden, who arrived in Pittsburgh on Friday to announce the $ 1 trillion infrastructure bill, said it was “miraculous” that there were no casualties and that only a few people were injured.
The September 2019 inspection showed that the bridge floor and high structure were rated 4 and the condition of the inspectors was poor. City officials’ latest inspection report on the city-owned steel bridge, which has been in place since September, was not available Friday, so it is unclear if the number has been updated.
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Infrastructure advocates say thousands of bridges across the country are of similar poor name but there are fewer falls. Many say the money did not meet maintenance needs.
How do bridge inspections work?
The Federal Highway Administration’s Bridge Inspection Program It has been developed over the years to include not only those in the federal highway system but also government and municipal bridges and underwater inspection laws and regulations.
Generally, bridges are inspected every two years, and some older or inferior bridges are inspected more often.
Municipal or state bodies that own and control the bridges submit inspection reports to state transportation departments that are required to submit them to the Federal Highway Administration.
What is a poor design?
Inspectors, trained engineers, usually inspect the bridge’s three main structures – the floor of the vehicle, the structure of the ship, and the subdivisions or wells that hold that structure. Other testing methods can be used to determine the weight of a rust bridge in the water or when necessary.
If one of the three bridge structures is rated at 4 points or less, the bridge is considered poor, said Andy Herman, president of the American Civil Engineers Association.
“Weak rating does not mean that bridges are unsafe, it does mean that one of them has been rated at that level,” Herman said. Bridge Infrastructure “
New bridges are rated 9, and bridges with little or no aging are rated 7 or 8. Bridges considered to be fair or satisfactory in the federal program are rated 5 or 6 – some signs of deterioration or a slight loss or cracking.
When a bridge reaches level 4, it means more damage or loss of part, but the main structural elements are still healthy. Stage 3 means those structural elements are starting to break down, and Stage 2 or 1 means there are critical issues or structural failure.
What happens after a bridge is evaluated for the poor?
One of the goals of the inspection program is to create a system that identifies repairs that need to be repaired before a bridge needs to be replaced.
Sometimes it is so easy to damage that you have to wait in line to repair the bridge and increase the frequency of inspections, said Jerome Hajar, professor and department chair at the North East University College of Engineering.
“When the bridge is added to the queue, it may take years before there is financial support to maintain those repairs, although it will be added to the state queue,” Hajar said. “The engineers have been working to repair as much as possible. The goal is to open safe and secure bridges, but the struggle is related to the lack of funds to repair aging infrastructure in this country,” he said.
In the event of further damage, authorities will limit the weight of the bridge by restricting heavy vehicles or traffic. In difficult situations when the structure is touched, a bridge can be closed immediately for repair.
The Interstate 40 Bridge, which connects the Arkansas and Tennessee rivers on the Mississippi River, closed in May, forcing thousands of cars and trucks to crack at one of the two 900-foot (275-meter) horizontal steel poles. After repairs, to turn around until the bridge opens at the end of July.
How many bridges are rated for the poor?
The American Roads and Transport Builders Association, which supports transportation infrastructure investment, publishes an annual report on the condition of the American bridge based on inspection reports. According to the most recent report using 2021 data, more than 43,500 bridges across the country are estimated to be 615,000 poor.
That number is less than the 4,000 nationwide reported poor in 2017. Proponents of her case have been working to make the actual transcript of this statement available online.
In Pennsylvania, the association’s report showed some 3,200 low bridges – about 1,000 bridges five years ago. However, more than 2,100 of these bridges have been damaged or require traffic restrictions.
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