Despite every precaution being taken and proper procedures being followed occasionally things break. Even big things like bridges or airplanes. When these events take place the best course of action is to try and understand what happened to prevent it in the future. In the aftermath of a bridge collapse or plane crash, specialists descend upon the scene and collect information about what went wrong and work hard to prevent similar incidents in the future.
Occasionally, there will be legal liability involved in such events and when that happens it is important to have a clear picture of the facts. If legal proceedings take place, often a professional such as an engineer expert witness will be called upon to interpret the investigators’ findings and help explain what happened. The science of forensics in such events can be fascinating. Understanding the forces at work and what trigger caused an event is like a mystery to be solved.
Investigations of structural failures like a bridge collapse involve many different pieces of information. An effective determination of the cause of failure is highly dependent on the quality of information collected immediately after such an event. For structural failures, the kind of evidence needed to determine a cause falls into roughly 3 categories.
Physical Loading
The load on a structure of any kind is the sum of all the different forces acting on the specific element that failed. In the case of a bridge, it would include the weight of vehicles traveling over the bridge, any construction machinery or materials on the bridge and any environmental loads such as high winds. Post collapse evidence may show that because of unusual circumstances the load exceeded the bridge’s design capacity.
Properties of Construction Materials
Time takes a toll on any type of material. Further, exposure to harsh environmental conditions can accelerate the deterioration of even the strongest materials. One part of the investigation will be to collect samples of the materials of the failed structure. These samples will be tested and examined carefully. This may include the use of specialized microscopes to view the molecular structure of the material.
Post-Failure Structure Configuration
Photographic evidence will be collected from a variety of angles to capture the configuration of structural members as quickly as possible after a collapse. This information provides key pieces of evidence about the order in which things occurred. Careful analysis of these photographs can lead back to the original point of failure.
When catastrophe strikes the best approach is to try and understand what caused the event to prevent similar events in the future. Dedicated teams of forensic scientists carry out just this task on all types of failures regularly. Because of the work of these professionals, changes are made to engineering specifications and construction methods that save lives.
