Statistisk analys av tung trafik : Studie av trafiklastens verkliga omfång baserat på BWIM-mätningar

Sammanfattning: This degree project aims to provide the Swedish Traffic Administration with information about the pressure distribution generated by vehicles with gross weights above 3.5 tons. The aim is to provide sufficient information regarding the pressure distribution to facilitate a possible change of today's deterministic design model to a probability based method. To realize the aim, BWIM-measurements carried out by the Swedish Traffic Administration in 2015, 2016 and 2017 have been studied. Measured data showed large variations depending on vehicle type, indicating that the data originates from different statistical populations. For the surveyed years, the data of interest are vehicles loaded to at least 80% of their permitted gross weight and a lognormal distribution has been found to be best representative of the pressure from traffic loads. The studied data also showed that the magnitude of the pressure increases with reduced vehicle length and that shorter vehicles whom are more frequently overloaded, subjects the structure with a pressure magnitude as great as twice the design value of today's 20 kPa. While plotting the pressure distribution, a positive skewness was observed. This indicates that the majority of observed vehicles load within the legal boundaries of their permissible gross weight. The vehicles that generate extreme pressures therefore represent a small fraction of all vehicles. Based on the studied vehicles the characteristic value of the 98\% fractile was calculated to 18,5 kPa. For the theoretical case where overloading was non-existent, this value decreases with 5%