Lessons Learned from a Recently Collapsed Bridge Posted by DC Cargo Mall on July 01, 2013

With the recent bridge collapse scare Washington has suffered earlier in May, only 15 days following the collapsed bridge in Minneapolis, FMSCA regulators have woken up to the shock and the media is still buzzing about it.

It has forced the World and America in particular, to question the cause, and for what measures are necessary to execute future prevention.

The question has been posed: Is it the weight of oversizetrucks and truckloads? Misinformed load-limit signs? Faulty inspections? Bridge constructional failure? Expired infrastructures?

In the case of this Steel Warren Truss Bridge, built in 1955, that held about 77,000 vehicles a day, it is mind-boggling at how this bridge has suddenly collapsed from a single truck…what was the straw that broke this enormous camel’s back?

Apparently though, the bridge had just been inspected twice last year. This led Washington state officials to believe the preliminary indications that the bridge running over Skagit River was not structurally deficient and fell because of the impact of the truck striking its support beams.

Washington Governor Jay Inslee told an afternoon press conference in Mount Vernon that the probable guess is that the truck had crashed into a couple of the bridge’s girders at a high speed, causing it’s consequential collapse.

Looking in the State’s bridge report records, this bridge had not been listed among the ‘Structurally Deficient’ – a title given to bridges that are not capable of carrying their intended loads due to its infrastructure.

It had though, been listed under ‘Functionally Obsolete’, meaning that it’s structural standards have expired and no longer work for the truck measurements and vehicle weights of today’s advancing society.

It was only in 1974, that the Federal-Aid Highway Act Amendments established the bridge formula as law, along with its gross weight limit of 80,000 pounds (36,000 kg). Being that the bridge was created before this law, its structure was not made for the elevated capacity limit that modernized laws allow.

The four-lane interstate connected Seattle and Vancouver, Canada as its main traffic line. The NTSB stated that they would conduct an inspection, further researching the cause, covering the entire 1,111 foot span of the bridge, including its substructure, deck, superstructure, and even underwater.

One could blame the bridges faultiness, but statements saying that newer, more competent bridges would have survived the same blow, were made.

The trucker was not actually one prone to mishaps and risky-business. Upright and honest as they come, William Scott cooperated with authorities, had not been arrested, and was backed up by his wife.

"I spoke to him seconds after it happened.” She relates.  “He was just horrified. He gets safety awards, safety bonuses ... for doing all these checks, for hiring the right pilot cars and pole cars,"

The tragedy, although not resulting in any fatalities, brought down two other vehicles with it, in its 40 foot plunge into the freezing cold waters of the Skagit River. The victims were rescued and brought to the hospital where they were treated for shoulder misplacement and similar injuries.

It’s surprising to learn that as many as 150 bridges collapse in just a year’s time, with many not receiving so much media attention. About 1,500 bridges collapsed between 1966 and 2007, and most of those were the result of soil erosion around bridge supports.

In special cases involving unusually overweight trucks (which require special permits), not observing a bridge weight limit can lead to disastrous consequences.

Inspecting trucks before and after loading, keeping up-to-date in quality loading equipment like tie-down straps and chains, staying informed about constantly evolving load limit laws, reading bridge capacity signs carefully, understanding the histories of each bridges infrastructures, staying on National Network Roads whenever possible and extra-vigilant driving are all small ways to successfully prevent a grand occurrence of repeat disaster like this one.

                                                                STAY SAFE!