Thank you for your answer. Unfortunately, I couldn't get a valid and logical information from the ones I thought there was, but there is not a lot of information on the subject where I live. The limited number of thesis studies I looked at were also very superficial, especially the loading issue was skipped. I guess the loading is done according to the truck classes selected based on the number of vehicles passing per hour. In the sources I looked at, only one truck was used. When we look logically, shouldn't the bridge be considered as fully loaded? Or shouldn't there be a distributed load acting in motion? I am waiting for your suggestions on the subject, especially in terms of source publications.