چكيده به لاتين
Due to the increasing need of the engineering society and the application of slab track railways, and lack of a useful formula considering all significant parameters to calculate the Dynamic Amplification Factor (DAF), in this article, the aim is to develop a formula for DAF in which all important factors are considered. To achieve this purpose, firstly the subject literature is reviewed and it’s found out that in none of the most used formulas in the world all of the most effective parameters are used simultaneously. According to the previous researches, the most determining parameters in DAF are rail corrugation, rail pad stiffness and velocity. In the next step, all required data are determined and classified by considering the existing regulations and studies; according to the condition of modelling and the quantity of data, it was distinguished using the regulation of Federal Railroad Administration (FRA) of USA is more proper. The corrugation data are the real surveyed data of Line 4 in Tehran Metro with 1 kilometer length in the year 2018 which was received from the related authority. To classify rail pads according to their stiffness, according to the other researches and implemented projects around the world, 5 levels of rail pad stiffnesses were determined as very soft, soft, Medium, hard, and very hard and a specific pad were nominated for each category to be run in the model. According to the limitations in running the model (limitation of time and devices to run the model) only 9 speeds were considered (20, 40, 60, 90, 120, 160, 200, 240 and 300 Km/h.) the using model in this study is the same model developed in Khajehdezfuly’s research. At last, the model results are discussed and a new formula is presented to calculate DAF. the presented formula indicated that DAF has a linear relation with the velocity. It’s also shown that the effect of rail pad stiffness and corrugation can be estimated by coefficients dependent on velocity or corrugation.
