Frictional behaviour of a polyurethane rubber sliding on concrete: Analysis of a slip and fall accident

A slip and fall accident which caused a severe ankle injury occurred when a 37 year old, 140 lb female stepped from the forecourt of a shopping centre onto the first of a series of paving stones laid across a bed of bushes. The first paving stone was 0.168 m below the level of the forecourt and not horizontal. Careful friction measurements using the accident shoes showed that the friction coefficient between a heel and the paving stone was 0.35 “ 0.05 when testing started. A transient effect caused the coefficient to increase to 0.55 - 0.05 during the first few tests. The effect of the paving stone slope was to reduce the effective friction coefficient by 0.12 so that the effective coefficient experienced by the accident victim at the time of the accident was 0.23 - 0.05. This is comparable to the friction coefficient experienced by the driver of a vehicle who applies the brakes while driving on a horizontal sheet of ice. In a lawsuit filed by the accident victim's attorney it is claimed that the management of the shopping center was negligent in that it created a hazardous situation when the paving stones were laid. The case has been scheduled for trial by jury.

Keywords:

• Friction
• Polyurethane
• Concrete Accident