Safety Barriers

SAFETY BARRIERS

• Safety barriers are designed to withstand the impact of vehicles of certain weights at certain angle while traveling at the specified speed. 
• They are expected to guide the vehicle back on the road while keeping the level of damage to vehicle as well as to the barriers within acceptable limits.
• Ideally a crash barrier should present a continuous smooth face to an impacting vehicle, so that the  vehicle is redirected, without overturning, to a course that is nearly parallel to the barrier face and with a lateral deceleration, which is tolerable to the motorist. 
• To achieve these aims the vehicle must be redirected without rotation about both its horizontal or vertical axis (that is, without ‘spinning out’ or overturning), and the rate of lateral deceleration must be such as to cause the minimum risk of injury to he passengers.

Objectives of safety barriers

• Reducing the likelihood of a vehicle crossing the central reserve and reaching the opposite carriageway.
• Minimising the damage to a barrier and vehicle, following vehicle strike and also reducing the risk to the workforce and work related congestion.
• Being maintenance-free and having a life of 25 to 50 years. 

According to the IRC (6-2000) the crash barriers shall be provided at the following locations: 

• For bridges without foot paths, concrete crash barriers shall be provided at the edge of the carriageway. 
• The type design for the crash barriers may be adopted as per IRC:5
• The design loading for the barriers shall be as per IRC:6. 
• For bridges with foot paths, pedestrian railing shall be provided on the outer side of footpath
• The railings of existing bridges shall be replaced by crash barriers
• In the urban environment traffic barriers are needed on urban motorways and primary distributors, where speeds are high and dangerous. 
• Traffic barriers should be erected on both sides of roads on embankments 6m high or more and on the outer edge of the roads where the radius is 850m or less and the embankment height 3m or more. 
• It is important to provide suitable and treatment for such type of barrier in view of safety. The ends of this barrier must either be embedded into ground by tapering down or these must be embedded into the rigid parapet wall of a culvert or specially prepared rigid parapet fit the purpose of embedding