Effect of Overloaded Heavy Vehicles on Pavement and Bridge Design

A large number of infrastructure projects have been undertaken in Taiwan in recent years because it is a developing country. These large-scale constructions have caused rapid growth in the number of heavy vehicles in service, as well as a dramatic increase in the size and weight of heavy vehicles. A very serious truck overloading problem has resulted, which significantly affects pavement performance and bridge safety. In the described study, weigh-in-motion (WIM) equipment was introduced to Taiwan's freeway systems. After data collection and analysis it was found that the average truck load factor for combined heavy vehicles computed from the WIM data collection was 2.7 times higher than the original design value, which already took into account 30 percent truck overloading. It was also found that computed axle load ratios for various types of heavy vehicles were dramatically different from the ratios given in the bridge design standard specification. Bridge deck designs for a simply supported bridge were studied. It was concluded that the current bridge design standard specification will result in a 28 percent underestimation of steel volume in bridge deck design.