Preventing structural collapse of Buildings, Bridges and Structures

One of the problematic issues facing construction workers recently has been the potential structural collapse of buildings and structures. The issue is particularly relevant during construction, demolition and refurbishment work.

The collapse of buildings and structures can cause serious injury and even death to employees as well as members of the public – the recent collapse of the wall in Swanston that resulted in the loss of 3 pedestrian’s lives is an example of these consequences.

Also the collapse of the building in Bangladesh recently was one of the most tragic, killing hundreds of people. But it isn’t just developing countries that are at risk of structural collapses, a bridge recently collapsed in Washington State, USA which resulted in the injuries of 3 people, luckily no one was killed during the incident.

The bridge over the Skagit River in Washington State unexpectedly gave way causing cars travelling along it to plunge into freezing water. Three passengers whose cars fell into the river were rescued and there were no fatalities.

There were previous safety concerns relating to the structural stability of the bridge, however it remained in operation.

According to officials, the structural collapse was caused by a truck hitting the overhead bar. The over-sized truck apparently collided with the span of structure, authorities have said which caused the already unstable structure to collapse.

This post from the website Catholic.org explains what happened:

2013051055river“For reasons unknown at this point in time the semi struck the overhead of the bridge causing the collapse,’ State Patrol Chief John Batiste said at an overnight news conference. The truck was able to make it off the bridge and the truck’s driver remained at the scene and cooperated with investigators, he added.

 

Three passengers were pulled alive from their vehicles after they plunged tens of feet into the water below yesterday evening. Rescuers said that no one died in the accident and all victims have been accounted for.

 

The Interstate 5 runs throughout the state of Washington, crossing the Skagit River at a number of different points. The bridge where the collapse happened was between Burlington and Mount Vernon.

 

 

Both directions of the highway have been closed in the area as both the north and southbound lanes of the bridge fell into the water.

 

 

Eyewitness reports said that there was a man stuck inside his truck that fell in the water during the collapse.

 

Source: http://www.catholic.org/national/national_story.php?id=51095

http://landing.newsinc.com/shared/video.html?freewheel=91227&sitesection=catholiconline&VID=24841572

The majority of structural collapses have occurred because of weather conditions, such as wind, foundations or temporary supports being undermined, later supports being remove prematurely or heavy impacts to the structure, like in the incident above when a truck collided with the structure. Occasionally more than one of these factors will combine to cause a collapse.

Some of the control measures that can be implemented include:

  • Monitoring structures and controlling for adequate stability to minimise the risk of structural collapse and the risk of injury to workers and the public
  • Ensure that structures can withstand extreme weather conditions such as strong wind and surface water or run-off.
  • If the structure’s stability is in question, a suitable large exclusion zone should be set up and until the stability is corrected.
  • If a structure is incomplete or the stability of the structure may be negatively affected by work on or to the structure, then temporary bracing should be considered.