WIM COMMISSION FOR ABU DHABI
All countries have overloaded trucks, to a greater or lesser extent, though it is usually more of an issue for road pavements than bridges. Taking a simple 4th Power Law approach, pavement damage is proportional to the axle load raised to the 4th power. For example, the 5th axle of the low-loader shown (right) is 46.1 tonnes. This generates as much damage as (46.1/8)4 = 1103 standard 8 tonne axles! Like many places, Abu Dhabi was concerned about the extent to which some of their trucks are overloaded and the resulting potential risk of damage to their roads and bridges. If violations like this are not addressed, they become widespread and roads can deteriorate over time. For most bridges, the problem is not so much damage as risk of collapse. If trucks with very large gross weight become commonplace, the probability of two of them meeting on the bridge becomes unacceptably high. ROD-IS received a commission through Professor Eugene O’Brien to review the existing situation in Abu Dhabi and assist with the development of possible solutions to mitigate the risks. They are planning a network of truck weigh stations. To make the process more efficient, they are considering Weigh-in-Motion (WIM) technology. The police can use these to firstly identify the times of day/week when overloaded trucks are most common. Then, when they are out in the field, they can use the sensors to identify the individual overloaded trucks before bringing them into the static weigh station.