Comparative Study on Applicability of Combined Extremum Methods for Extrapolating Bridge Vehicle Load Effect

Abstract:

The effects of long-span bridges include the overall effect of long loading length and the local effect of short loading length. Their extreme value may be affected by multiple traffic loading events. Two combined methods should be used for extreme value prediction on the mixed traffic flow. The combined method can solve the problem that the traditional extreme value theory is not suitable for samples with different bottom distributions. To further clarify the application range of the two combined extreme value methods in various traffic flow scenarios， combined with the simulated traffic flow under different traffic conditions， as well as the effects on a long-span suspension bridge， based on the analysis of the assumptions and algorithms of the two methods， the effect extreme value prediction results at different loading lengths are calculated， and the influencing factors and applicable scope are discussed. The results indicate that the combined generalized extreme value method is more sensitive to the sample size change and the bottom distribution fitting. When the samples are insuffcient， the combined generalized Pareto distribution method is enjoyable. However， when the samples are sufficient， the combined generalized extreme value method tends to be easier for calculation. The distribution fitting curve of each event in the long loading length effect extreme value presumption doesn’t have a cross area on the condition of sufficient samples， and the extrapolation extreme value in the multi-event mixed situation is directly determined by the controlling event （peak status）.