Forensic engineering

[edit] Introduction

Forensic engineering is the application of engineering principles to discover the underlying causes of structural, material or product failures or malfunctions. If a failure results in loss of life, personal injury, economic loss or damage to property, the uncovered causes may form the basis for civil or criminal proceedings.

Seemingly minor items that may not initially appear to warrant investigation can be the subject of forensic interrogation if they have caused accidents leading to personal injury. This can include a host of small products, appliances, consumer products and hand tools. Breast implants and heart valves have also been investigated where they have led to adverse and life-threatening bodily reactions.

The discipline can also involve reverse engineering, whereby processes and procedures that are thought to have led to an accident are retraced. Reconstructing the sequence of events that led to a failure or accident can be enlightening, such as measuring tyre marks on a road to gauge the speed a vehicle was travelling immediately before an accident.

Forensic engineers can be of huge value in determining why failures occur in the materials, structures, products and components involved in building failures, structural collapses, air crashes, machine failures and other unpredicted occurrences. Even in what may seem to be 'mundane' motor vehicle crashes, forensic engineers may get involved if a component failure is suspected as contributing to the accident. That some of these failures may result in loss of life or economic loss or disruption makes the work of forensic engineers critically important, perhaps helping prevent similar occurrences in the future.

[edit] Analysing the causes of failure

Investigating any failure requires the collection of data that is linked to the people, products, materials components and structures that may have failed. This can involve extensive information gathering including eye-witness accounts, measurements, soil samples, material fragments, current operating modes of machines, original design data, installation/construction conditions, site photography, quality control, weather conditions and so on.

Forensic engineers can make use of a host of different technologies, such as optical and scanning electron microscopes, spectroscopy, nuclear magnetic resonance, X-ray radiography and computed tomography, as well as more simple observations such as the use of hand lenses and the naked eye.

[edit] Construction failures

The following projects involved detailed forensic engineering to discover the causes of failure.

[edit] Tay Bridge disaster

One of the most notable examples of structural collapse in British construction history in December 1879, the Tay Rail Bridge spanning the River Tay at Dundee, Scotland failed dramatically as a locomotive was passing over its central span. The entire train plunged into the river killing all 75 people thought to be on board. The investigation pointed to numerous causes that led to the disaster including a 70mph gale, poor manufacturing quality in some structural components and inadequate site supervision.

[edit] Ronan Point

In May 1969, Ronan Point, a 22-story residential tower block, suffered a catastrophic partial collapse only two months after it opened to council tenants. Four people were killed and 17 injured. A boiler explosion on the 18th floor that should have been contained by the construction led instead to the progressive collapse of one corner of the building. The forensic investigation which fed into the Griffiths Inquiry found that the method of wall support between floors was inadequate and the ability of the construction to contain such a small blast was grossly inadequate, given the lack of injury to the person who lit the match in the fateful flat. For further details see Ronan Point.

[edit] Grenfell Tower

In another multi-storey tower block, the fatal fire of June 2017 at the 24-storey Grenfell Tower in West London involved multiple fatalities and was caused by combustible insulation added to the outside of the tower’s structure. For further details see Grenfell Tower.

[edit] Related articles on Designing Buildings Wiki

• Adam Curtis - The Great British Housing Disaster.
• Approved Document A.
• British post-war mass housing.
• De la Concorde overpass collapse.
• Defects in construction.
• Grenfell Tower fire.
• Modular buildings.
• Offsite manufacturing.
• Prefab bungalows.
• Prefabrication.
• Ronan Point
• Structural failures.
• The structural condition of Easiform cavity-walled dwellings (BR 130).