نشریه فناوری حمل و نقل
پیاپی 33 (پاییز و زمستان 1398)

In this paper, the effects of rail vibrations transferred from the ground to the building in the vicinity of the rail are studied. The additional forces mostly produced in the contact area of the wheel and structure’s rail influence on the building in the vicinity through the soil underneath. The building is a concrete chamber located between 2 high speed railroadand in 2 meters distance from them. The Ansys software was used which can model the train forces, soil, rail and building’s components. One of the ISO 14837-1 curves was used as a raw curve of train vibrations’ effect and was made ready to enter in the software by mathematical transformations. The results of the software model have been studied in case the vibration frequency received by the building is equal to one of the effective natural frequencies of the building, which leads to damage to the joinery of the building (if the building is old or historical, it will overturn). By using damping layers in the building, the effect of train vibrations on the building adjacent to the rails is greatly reduced, and with this solution, damage is not caused even in the joinery of the building. The damping layers are made of rubber and polyurethane, which is produced by the German company "BSW". Another way to reduce the resonant effect is to increase the damping of the structure in different ways.

Capacity is one of the most important factors in most constructions, designs and evaluations in the field of transportation planning and road engineering. Capacity awareness, along with measuring existing traffic demand and predicting future traffic demand, allows the traffic engineer to design and plan transportation facilities in a way that effectively meets the needs of the community. In this paper, while reviewing the common methods of analyzing the capacity of multi-lane roads, an attempt is made to present the localized method in Iran.

Oil revenues make up the bulk of government revenues and directly or indirectly particulary affecting national economic variables, in road transportation. Beside, the road transportation sector because of the major contribution to the movement of goods and passengers by this section in our country, is counted more significantly and Efficient and proper management of road transportation activities can accelerate the growth of this sector. The aim of this study is to evaluate the effect of oil revenues in the resources sector of country`s road transportation section that for this purpose, using OLS model and Eviews computer software, the impact of oil revenues on Providing investment resources in country`s road transportation section during the 1989-2016 is studied. According to the findings, increasing of one percent in country`s oil revenues after a year, real investment in the road transportation sector has increased at a rate of 0.38 percent and also the increase of one percent in added value in country`s road transportation section, Actual investment country`s road transportation section has increased about 1.84 percent after one year.

Countries in the developed world have encountered high maintenance cost for deteriorated transportation highways and replacing them despite budget deficits, and decreasing other expenses are no longer applicable. Since 1980s, the privatization policy has served as a strategy to finance state-owned companies from the state budget, raising their efficiency and empowering the private sector. Therefore, privatization in these sectors could be used as an effective way to finance the maintenance costs and management of highway construction, and in this article, the threats that may arise from lack of highways are outlined which could be mitigated by privatization, and the obstacles as well as the advantages and disadvantages of privatization and its various aspects are also investigated.

Safety problems and dangers that exist in different parts of a road can kill many people. Thus, due to the high probability of accidents in those areas, the probability of users being at risk and road casualties increases as a result. To have safer road trips and increase the level of satisfaction of road users, road safety audits will play an important role in reducing the rate of road accidents. Always visits to check road safety conditions, if a set of conditions and criteria are considered, can significantly identify areas of the route where the potential for accidents is high. Identified sites do not necessarily have the same risk of loss and damage and should be prioritized in order to secure and provide short-term and long-term solutions. For this purpose, in this study, considering the two parameters of probable accident severity and the probability of an accident, the accident hotspots of a freeway were ranked in terms of risk. This ranking has been proposed using the risk matrix and has been implemented for the Karaj-Qazvin freeway in Alborz province. 

Road slope stabilization is one of the most common issues in reducing financial and life risks. Use of efficient and cost effective approaches for stabilizing earth slopes is a crucial matter. Due to Road growth, stabilizing of endanger slopes and insuring its safety is one of the basic concerns for engineers. With regard to regional condition, site importance, economical status, and many other factors, using common methods of stabilizing are diverse. One of these appropriate approaches for reinforcing earth slopes is the use of stone columns. Using stone columns, which, besides its simplicity and comfort implementation, is also very economical. The object of this research is presentation of experimentally and numerically investigates stone column stabilization of earth slopes, and investigates case studies about using stone columns in road slopes stabilization.

According to the wide usage of energy absorbers in various engineering structures and in order to prevent damage to life and property, the analysis of behavior of absorber collapse is necessary under different loading conditions, geometric and boundary condition. In this research, collapse process of thin-walled tubes is simulating using Abaqus finite element software to validate the simulation results, the present model compared to previous experimental results. After ensuring the accuracy of numerical simulation models to investigate the effect of combined cylindrical tubes will be discussed. At first case, the tube with a circular cross-section into the tube with a square cross-section and placed under axial loading .In another case, a combination of external and internal tubes is changed. In other words, the tube with square cross-section is placed inside the tube with circular cross-section and numerical simulation is repeated. Then comparison criteria of combined cylindrical absorber collapse (including maximum crushing load, mean crushing load, the amount of energy absorption and specific energy absorption) is investigated.