Rope Wire Failures – Forensic Investigation and Services.

Investigation of the Rope wires at Construction Site:
Steel wire ropes material finds typical applications in the building, construction sites, marine and elevator industries, involving various types of lifting equipment such as mobile and tower cranes, synchro lift hoist and winch ropes, as well as elevators and cable carts. There can be Catastrophic failure of these wire ropes can occur without warning, causing damage and endangering lives.

Forensic Examination of the rope wire:
The failure of the rope wire can be for different reasons and can easily be detectable by the forensic examination. However microscopic forensic examination is usually required to ensure that all features are seen that has caused the failure of the rope wire. Such forensic examination can be exacting because ropes can be made of hundreds of wires and each fracture has to be individually examined. A further difficulty is that when a rope fractures, mechanical damage can occur as a result of the event, this can be confused with pre-accident damage unless the examination is thoroughly done.

The extent of damage to elevator rope failures is often severe and it may sometimes be difficult to distinguish between pre-existing damage and damage occurring as a result of the failure. Thus, when a rope fractures, mechanical damage can occur as a result of the event. However close forensic examination of wires away from the failed end can show the true condition of the wire rope prior to the failure. Wires that have been worn over a period of time exhibit flat surfaces and fractures often occur across these flats.

Various kinds of Failures of rope wire:
Overload: There can be a failure in the rope wire or wear and tear in the rope wire because of the load on the wire is too heavy. However this is the least common reason for the failed ropes seen at our laboratory.

Prior Damage: This causes because ropes can come into contact with the side of a building or another crane. A rope might slip out of a sheath and suffer damage. Mechanical damage weakens the rope and failure can occur thereafter.

Wear and Tear: In normal course of the work the ropes wire pass over sheaves and are wound onto a drum, providing opportunity for contact and wear to occur. In a dusty construction site the grease can be contaminated by dirt particles, with the most common particle, silica, being very abrasive.

Corrosion: Many ropes wire are kept outside in open area and some are close to the sea and may be affected by chloride contamination. If they are not frequently greased the deterioration can happen rapidly. Even indoors, humidity can cause corrosion, for example with elevator ropes, particularly in the tropics. Most of the failures we see are a result of wear and tear, corrosion or combination of the two. Synchrolift hoist cables used in shipyards are particularly susceptible to corrosion due to the seawater environment. Corrosion to internal wires is often unseen from the outside while external wires are covered with costly grease and there is reluctance to remove it for inspection.

Fatigue: Repeated flexing of ropes can lead to fatigue. Sometimes fatigue follows on from wear and tear.

Our Forensic Services in Rope Wire Analysis:

We have a team of forensic experts with our forensic experience who will analyze the rope wires in our metal forensic lab and will be able to assist in the following areas:

» Determining the cause and reason of wire rope failure in:

• Cable Cart;
• Mobile and tower Cranes;
• Construction site;
• Elevator;
• Other various types of lifting equipments etc etc.

» Evaluate the condition of remaining wire to determine its fitness for service.
» To see the maximum load capacity or the breaking load of the metal rope wire.

M/S J. K. Consultancy
Vardhman Star Citi Mall, 
321, LSC - III, Sector - 7, 
Dwarka, New Delhi - 110075, 
India. 
Mobile : 09810411824, 09868106032
E-mail : info@jkconsultancy.in
Website : www.jkconsultancy.in