Influence of number and quality of weigh-in-motion data on evaluation of load effects on bridges : doctoral thesis
Vpliv števila in kvalitete podatkov tehtanja vozil med vožnjo na določitev obremenitev mostov : doktorska disertacija

english

doktorska dela

2017

bridge   civil engineering   convolution   data quality   dynamic loading   freight vehicles   measurements   statistical methods   thesis   traffic loading   weigh-in-motion

Univerza v Ljubljani, Fakulteta za gradbeništvo in geodezijo
(Obvezni izvod spletne publikacije)

The thesis is dealing with the influence of number and quality of weigh-in-motion (WIM) data to calculate load effects on bridges. Weighing in motion is the only method that provides continuous and unbiased information on traffic loads, but the data contains errors as a result of environmental influences and measurements that can not be constantly monitored. Presented are improvements of bridge WIM technology, which replaces the weighing sensors in the road surface with instrumented bridge superstructures. The system had many advantages, but also shortcomings that prevented its long-term installations. Proposed are a new installation procedure for the sensors that detect axles of the vehicles, a new way of calculating the influence lines, which is based on the responses of crossing vehicles, a method that deals with measurement errors caused by cracks in concrete, and a procedure that takes into account the impact of temperature on the behaviour of bridges. Also shown is the procedure to determine the dynamic loads that the commercial vehicles induce, and their impact on the measurement results. The following chapter elaborates quality control of bridge WIM data. The proposed procedures check and correct typical errors that occur during the measurements, assess quality and reliability of data and significantly shorten the time needed for its verification. Simulation procedures, which are predominantly used for calculating the traffic load effects on bridges, are complex and time intensive. The convolution method, a less demanding procedure appropriate for short to medium-span bridges, was thoroughly investigated. The results were compared with the ones obtained by comprehensive simulations. Convolution method has facilitated the detailed analysis of the impact of quantity and quality of WIM data on calculated moments and shear forces, for simply supported bridges with spans between 5 and 45 meters, which represent the vast majority of all bridges. The size of data samples was varied to investigate its influence on the load effects. Then, various data sources, with respect to quality of data (measured, electronically corrected, visually verified), were examined. The results give clear indications about the required number and quality of WIM data for effective modelling of traffic loads on bridges.

12.05.2023