Live Load Models for Ethiopian Highway Bridges using Truck Weigh-in-Motion Data

For the structural analysis of highway bridges, as heavy trucks cause large loads, development of live load models based on empirical data is critical. Therefore, weigh-in-motion (WIM) technology provides essential insights into axle configurations, vehicle weights, and traffic patterns that is vital in bridge construction and evaluation. This research examines the impact of truck loads on bridges, using information obtained from the WIM systems in Ethiopia. A new live load model specific to the country is developed based on 5 years of WIM data, encompassing 45,197 heavy truck loadings identified through systematic sampling methods. For simply supported bridges up to 50 m, the static load calculations are also performed, and a statistical extrapolation is used to obtain the results for a 75-year return period. Results showed that the extrapolated WIM data exceeds the factored HL-93 load effects by 15% on average. Finally, live load models which reflect the country’s actual loading conditions are proposed, with an error of below 9.48% compared with extrapolated data.