پژوهشنامه حمل و نقل
سال پانزدهم شماره 4 (پیاپی 57، زمستان 1397)

As the asphalt temperature decreases, the tensile stress increases. If the tensile stress in the asphalt is greater than its tensile strength, the pavement asphalt cracks. Previous studies have focused on improving asphalt performance at high temperatures, while asphalt performance is neglected at low temperatures. Therefore, the purpose of this study is to investigate the effect of ZycoTherm nano-materials as an additive and asphalt modifier at low temperatures. For this purpose, four types of asphalt mixtures were prepared from the silica materials of the plant where the asphalt was produced. The first type was used a control sample with no additives, the second type was prepared with 0.1% nanocomposite additive, the third type with 0.15% of the additive and the fourth type with 0.1% additive and cement filler. Each type of mixture was tested with three specimens in a dry state and three samples in a saturated state, a total of 24 test specimens. Indirect tensile strength and tensile strength ratio values of specimens were measured in dry state after the freezing and melting cycle on the samples. The results showed that 15 % of ZycoTherm could increase the tensile strength in the dry state, but the effect of 0.1 % of ZycoTherm was higher than the 15 % of ZycoTherm. According to the results of the indirect tensile strength test, the highest strength belonged to the additive of 0.1% ZycoTherm nanocomposite with cement fillers, which indicates that indirect tensile strength of samples has improved in dry state and after the freezing and melting cycle.    

For each product, the manufacturer's guide for how to use it to communicate with the consumer is considered, in order to allow optimal and safe use of this product becomes available. On the highways , as well as products that are used by thousands of people’s daily, tools for effective communication between manufacturers, designers and managers with their users must be considered in addition to providing traffic safety, also provides the possibility to use highways with maximum capacity. Traffic signs are the most important tools for communication with road users. In order to transmission the messages, figures, symbols and text use in traffic signs. If the traffic sign messages which is generally provided in the form of a symbols, doesn't understand by drivers, the goals of installing traffic signs will not be meet. Perception of different traffic signs are not the same between driver’s Perceptions is different from signs to signs. In this paper, we investigated the effects of traffic signs’ application on driver’s perception. Traffic signs are categorized in three groups: “all-purpose signs”, “average usage signs” and “less common signs”. For each group, 4 traffic signs were examined. In order to evaluate and analyze, a survey study with questionnaire was designed. During five days of questioning at police station in Zanjan-Miyaneh road, 300 questionnaires were completed through interviews with drivers. For validation, similar study was carried out by filling out 40 questionnaires in Zanjan-Bijar road. The resulting data were analyzed using chi-square test and correlation coefficients test. The results showed that overall drivers’ perception of traffic signs was 53.7%.  However, driver’s perception from traffic signs are not the same and for all-purpose sign, average usage signs and less common signs was 88.3%, 49.3% and 23.3%, respectively. The results reverent that with the increasing traffic signs application, driver’s perception from traffic signs will increase and the correlation is about 0.53.      

Destination and mode choice play an important role in travel demand analysis and policy assessment as a consequence. To study these two choices, most researchers have used multinomial logit which suffers from the assumption of all error terms being independently and identically Gumbel distributed. This leads to the inability to consider the non-systematic heterogeneity in the alternatives. Heteroscedastic extreme value model assuming independent and non-identical distribution can analyze the alternatives with non-systematic heterogeneous utility. The purpose of this paper is to analyze this heterogeneity and compare results with those of multinomial logit in destination, mode and simultaneous destination- mode choice for shopping trips in Qazvin city. Three choices for destination based on distance; and three choices for modal split including walking, private car and bus (totally 9 choices) are considered. The results for 1570 person- trip according to different criteria (such as log-likelihood function and likelihood ratio index) show the superiority of heteroscedastic extreme value model in destination and mode choice and superiority of multinomial logit in simultaneous destination- mode choice. It is also observed that by increasing the number of alternatives, the non- identical and independent assumption of error term does not increase the explanatory power of the model: travelers consider the non- observed factors as independent and with the same distribution. This paper is a step towards relaxing choice constraints, allowing researchers to consider heterogeneity of the alternatives.

Different methods have been developed and used for the excavation of tunnels. These methods generally have common points, but each of them is different in execution phase and this is the reason why they are categorized. Selection of an optimal method for tunnel excavation includes full knowledge of the tunneling methods and the parameters affecting them. Geometric characteristics, geological and geotechnical properties, project conditions and existing infrastructure, project completion time, and environmental issues are some of the important parameters which must be studied and evaluated. Also, the prediction and control of settlement in terms of safety and economic point of view has considerable importance in urban areas. In recent years, the shallow tunneling method (STM) has been used to excavating underground spaces such as metro stations and similar spaces in different soils, which have many interests in urban areas due to their lack of traffic jams. According to plan of line 2 Shiraz subway, a Crossover is constructed between the Rahmat and Dolat station in the middle of two main railways of the route. The length of the Crossover is about 136.5 m and its overburden is about 7.5 m and its diameter is about 22 m. This paper focuses on selecting the appropriate excavation method for crossover using STM method based on numerical modeling with FLAC3D software. The purposes of three-dimensional numerical modeling are evaluation of settlement during excavation, and determination of the best excavation method with the lowest settlement rate. Different methods have been investigated with different drift and sections division. Finally, two applicable methods are presented in this paper and the best method with the least settlement was introduced as the preferred option. Based on the result, maximum settlement at ground surface was 2.58 cm in the preferred option.

Identification of hot spots is an important activity for improving the overall safety of roadway networks. A central issue in comparing HSID methods is the development and selection of quantitative and qualitative performance measures or criteria. In this research, The seven commonly applied HSID methods (accident frequency (AF), equivalent property damage only (EPDO) based the coefficients of the  PIARC, P-value (Islamic Republic of Iran Ministry Roads and Urban development), accident rate (AR), combined criteria, empirical Bayes (EB), societal risk-based) were compared against six robust and informative quantitative evaluation criteria (the site consistency test, the method consistency test, the total rank differences test, the total score test, sensitivity test and specificity test). These tests evaluate each method performance in a variety of areas, such as efficiency in identifying sites that show consistently poor safety performance, reliability in identifying the same hotspots in subsequent time periods .To evaluate the HSID methods, three years of crash data from the Jiroft-Kerman road were used. Analytical Hierarchy Process (AHP) method has been used for determination the importance coefficients of evaluation tests and as a result, showed that the total rank differences test is the most appropriate test. Also the quantitative evaluation tests showed that the EB method is the most consistent method for identifying hotspots and accident frequency, accident rate and combined criteria methods after EB method cause the identification of hotspots similar, that they have similar performance and their evaluation results is the same, have the best performance. Following these methods, the P-value, equivalent property damage only based the coefficients PIARC, and societal risk-based respectively. Societal
risk-based method performed worst in all of the tests. It should be noted that advantages associated with the EB method were based on crash data from one the road Iran country and the relative performances of HSID methods may change when using other crash data. However, the study results are consistent with earlier findings.    

One of the degradable industrial materials is glass wastes. Many methods have been utilized to mitigate the destructive environmental effects of glass wastes. One of the important methods is to utilize them in different industrial sectors. Recently, the use of this material in pavement industry as a component of asphalt mixture has attracted researchers’ attention. One of the problems in the application of glass wastes in asphalt mixtures is the moisture sensitivity of asphalt mixtures. In this study, asphalt mixtures fabricated using 0, 5, 10, 15 and 20% glass wastes as fine aggregates. A 60/70 binder was selected and it was modified by two anti-striping Nano materials named Nano aluminum oxide and Nano iron oxide. In order to evaluate the performance of mentioned additives, moisture susceptibility test based on AASHTO T283 are conducted. The results of this study showed that the use of glass wastes increases the moisture susceptibility of asphalt mixtures. Higher glass content increases the moisture susceptibility of asphalt mixtures. Also, the use of mentioned additives led to an improvement in the properties of asphalt binders. It decreases the acidic properties of modified binders. Hence, the cohesion between asphalt binder and glass is increased and it provides a better performance against moisture damage in comparison with base materials.  

Each year, about 60% of the construction budgets of metropolises are allocated to transformation and traffic domains for developing physical infrastructures and facilities such as rapid transit lines, passages and streets, bridges, overpasses and underpasses for pedestrian crossing, highway Interchange to remove the direct impacts of vehicle, bicycle and pedestrian paths, public transport fleet, parks, terminals, stations, vertical and horizontal lining for passing pedestrians, intelligent traffic management systems, vertical and horizontal guides signs and panels , parking lots, etc. those budgets are mainly paid by people from toll payment. For having appropriate planning, with regard to strengths and weaknesses of internal environments, opportunities and threats dominating the external environment of municipalities, proper spending in required and prioritized places, preventing subjective actions of managers and individual-centered views, and reinforcing plan-oriented approaches, long-term strategic planning seems necessary. As a result, operationalizing strategies of developing this type of public transportation with the prioritization as: Diversification Strategy (ST) as the first priority;: Revision Strategy (WO) as the second priority;: offensive strategy (SO) as the third priority; and: Defensive Strategy (WT) as the fourth priority should be at the top of authorities’ executive programs for obtaining the development of taxi in Ahvaz Metropolis.    

Each of different railway projects has their own benefits and special circumstances.thus prioritization of these projects to allocate budget efficiently and ensuring to reach the maximum of indices for desired results always has a paramount importance to decision makers and executive managers. In this study, three railway projects have been prioritized by ANP method, and the inner dependency of criteria was calculated by DEMATEL method. The results showed that in two scenarios(without criteria inner dependency and with criteria inner dependency) the Doroud-KhorramAbad-Andimeshk project has the highest prioritization in comparison to other alternatives. also sensitive analysis showed that by increase the weight of "construction costs" criteria, the results changed in two points. The framework that is presented in this study can be a suitable framework for decision-makers to the proper allocation of funds in different railway projects and take effective criteria to reach the highest demands and expectations of railway projects.      

The economic goals of developing countries are to improve trade, including exports and presence in international markets. The emergence of effective policies for export development is to identify the factors affecting exports. One of these factors is transport infrastructure. Which is one of the most important factors shaping modern society today? The essential role of transport in shaping the economic structure in societies has always been the focus of transport infrastructure in the context of economic development. In the meantime the rail transportation due to lower power, lower emissions, safety and high passenger capacity has more benefits than any other fleet. The objective of this study, the effect of rail infrastructure as a sub-segment of transportation on the volume of exports of countries D8 during the period 1995-2014 using panel data and GLS methodology has been investigated. In this study, the rail lines have been used as a railroad  infrastructure. The results indicate the positive and significant impacts of rail infrastructure on the volume of exports of countries.    

The purpose of this study is to analyse the financial aspects of dredging for ports and harbours that need to maintain ship accessibility. The volume of sediment produced is usually significant in size and in expenses to manage. This paper develops a financial modelling and analysis for the management of maritime sediments using a financial model. This model can be used as a decision-making support tool by shareholders in ports, consulting companies and observers. To achieve this, a decision support tool has been developed and almost every available data has been used from a wide range of different countries. This model analyses a wide range of dredging production processes until the final usage. Required inputs include sediment characteristics, logistics data, financial scale of dredging in national level and direct expenses. This paper explains the potential of the decision support tool for financially evaluating a wide variety of dredging management options, as well as providing valuable information for the optimal management, and provides a comparison between traditional options and potentially useful scenarios.    

Decomposition method one of the most popular methods to study for changes to energy consumption that it changes the energy consumption divided to three effect contains productive effect, intensity effect and structural effect. The results of decomposition of energy consumption in the transport sector in Iran shows productive effect, intensity effect and structural effect, to arrange the most important role in explaining the changes in energy consumption in this sector. Estimation of energy intensity model in the transport sector to SVAR method showed that in the short term the energy intensity, energy consumption, energy prices, capital formation, labor force and value added, most contributions described in energy intensity and in the long-term energy prices, value-added, labor force, energy consumption, energy intensity and capital formation most contributions described in energy intensity. In the short term energy intensity with energy intensity, value added, capital formation, labor force and energy prices positively and negatively associated with energy consumption. In the long term, energy intensity with energy intensity has a positive relationship and with the variables energy consumption, value added, capital formation, labor force and energy prices is negative.  

One of the most important aspects of human presence in urban spaces, which causes the vitality and dynamism of these spaces, as well as their social role, is the pedestrian movement. Pedestrians are vulnerable road users and damages to them are often irreparable and irreversible and cause injury or death. The purpose of this study was to determine the percentage of using pedestrian bridges in Tehran as well as environmental and human factors affecting the use or non-use of pedestrians crossing at the bridge's influence. Several environmental factors such as the median pedestrian barriers as well as human factors such as the age and the personal characteristics were considered in this study. In this research, decision was made in a fuzzy environment, which is a multi-value environment. The knowledge base used in an expert system is formed using fuzzy logic and could be used as a fuzzy decision support system for managing and planning for the construction of new pedestrian bridges or for modifying existing bridges. The results of this research can be used to identify high-capacity bridges for equipping other bridges, locating for the construction of new bridges, assessing the status of each bridge and its use. The results show that the most effective factors for using the overpasses by pedestrians were the bridge facilities among the environmental factors and the perceived identity among the human factors. Having compared the results of this study using the fuzzy reasoning model with the real outputs show a 98 percent correlation and the 20 percent error in estimating the probability for using the pedestrian overpass to cross the street.  

Being aware of the pavement structural condition can play an effective role in implementing an effective pavement management system. An effective structural number can be considered for pavement design, maintenance and rehabilitation, detection of homogeneous sections, prediction of pavement deterioration, and identification of sections requiring additional field tests. One of the most common methods of calculating structural number is the use of non-destructive methods and equipment, such as Falling Weight Deflectometer (FWD). However, the cost of data collection, the need for traffic control and speed constraints are important things that have caused the use of the FWD to be limited at the project and especially the network level. In this paper, it is tried to determine the effective structural number by considering roughness and surface distress with fast and relatively economical methods. For this purpose, 52 km of arterial roads in Kermanshah and Ilam provinces were studied with different specifications such as traffic, age, pavement thickness and distresses. Also, for the determination of deflection, Roughness and PASER index (surface distress), assessment devices such as FWD, RSP, RD-3VV, and visual survey were used respectively. In order to determine the effective structural number, the roughness index (IRI) and PASER index, were considered as input variables in modeling. Also, power regression relation, polynomial linear and neural network models with different architectures were used. The results of the proposed model show that it is possible to determine the structural number with high accuracy and low error. In addition, the superiority and ability of neural network models to estimate the effective structural number, is significant compared to other regression models.    

In 1929, when the Warsaw Convention was ratified, it was regarded as a success in the air law system. Even now, despite the fact that it lasts for about a century, despite the rapid changes in the air industry, it is a decisive document. Our country has already ratified the Warsaw Document and its amendment, the 1955 Hague Document, but has refused to accede to the Montreal Convention of 1999. The Montreal document was approved with the justification, which is in line with recent advances in the aerospace industry. Additionally, since a number of documents were adopted between 1929 and 1975, there was a tight legal system in aviation. The adoption of the Montreal Convention ended this legal turmoil. Since our country has not approved the Montreal Protocol, this article should be considered. Therefore, the purpose of this article is to examine some of the rules of the Warsaw Convention, adopted in 1929, and to compare those rules in the Montreal Convention of 1999. We are trying to answer the question as to whether we should approve the Montreal Convention.  

Transportation is assumed as one of the major constituent elements of the city and all urban parts are related to this important element and this relationship is bidirectional. Today due to rising trend of urban population and as the consequence of urban transportation rate and several problems like increase in rate of ownership of vehicles, lesser use of public transportation system, air pollution, and rise of accidents etc. the necessity for paying attention to non-motorized transport has become more evident. The current research is of applied type and it generally aims to analyze the barriers and challenges of realization of non-motorized transportation system in Mashhad city Region 1. It has been tried in this study to discuss about subject of urban transportation and to lead it to non-motorized transportation and to review the factors that hinder realization of this objective in Mashhad city Region 1. Therefore, 2 variables are analyzed including lack of satisfaction and security of bicycle users and environment, and with respect to comments from 328 male citizens by the questionnaires completed by them and after analysis on research hypotheses and questions these variables are ranked using Friedman test at the end and among 2 variables, the environment factor is considered as one of the foremost barriers against realization of non-motorized transportation system within the studied range. At the end some strategies are suggested to accomplish this goal as well.  

In this research, glass fibers in the length 12 mm and content of 0.3 percept by the total weight of mixture were used to amend the performance of the warm mix asphalt (WMA). Wheel track test was performed in two states of dry and wet on unaged and short-term aged samples. The post compaction, stripping inflection point, dynamic stability, final cycle, and the number of cycles corresponding to 12.5 and 20 mm rutting depth as well as rutting rate were employed to evaluate the performance of rutting resistance and moisture susceptibility of samples. The results showed that while the incorporation of glass fiber improves all the rutting resistance criteria, it has an insignificant impact on moisture susceptibility of WMA. On the other hand, short-term aging enhances both the rutting and moisture-damage resistance of mixes. Moreover, regression equations were developed to predict C-20 criterion from post compaction, dynamic stability and rutting rate criteria.  

Coastal sandy soils cover a large part of the soil of northern part of the country. These soils will have problems due to loose characteristic and lack of proper strength properties for roads building. Beach sand is encountered with the wash-out phenomenon due to uniform gradation and lack of cohesion at the time of the water flow in an unconfined state. To solve the problem of these soils, various methods such as reinforcement with different materials are used. In this research, the effect of adding various percentages of polypropylene fibers to non-cemented and cemented sand on the mechanical characteristics of sandy soils of Babolsar beach was investigated by performing direct shear tests and triaxial tests. According to the results, adding these fibers improves the internal friction angle, cohesion, maximum strength, Failure strain and residual strength of sand. Comparison of the results of direct shear tests and triaxial tests showed that, due to the proper orientation of the fibers relative to the direction of main tensile strains in triaxial tests, the efficiency and their effect on the soil resistance behavior in triaxial samples were more significant than direct shear tests.    

Look-ahead control is a new approach for reducing fuel consumption in road and rail transportation industry. In this approach, considering the slope of ahead path, speed changes were decided on using a fuzzy controller so that, if there is an uphill on the ahead path, speed should be increased so that the vehicle could easily pass and fuel consumption is reduced. In the structure of this algorithm, a part of the ahead path is considered as a look-ahead window and the average slope of its inside points indicates the slope of the ahead path. Length of the look-ahead window and its distance from the vehicle's instantaneous location are two main parameters of look-ahead algorithms that affect their performance. In this paper, unlike the previous studies in which length and location of the look-ahead window kept constant during the whole path, these two parameters changed dynamically by a fuzzy controller according to the speed of the vehicle and slope variance of the points inside the window. Results of the simulation of train motion using the proposed algorithm demonstrated better performance of the algorithm and increased fuel efficiency.  

Selection of appropriate pavements deicing materials is one of the main concerns of roads maintenance officials. Investigations show that many researches have been carried out on effects of deicing/anti-icing materials on concrete, however a few researches have evaluated the effects of these materials on asphalt mixtures and these few researches have generally concentrated on moisture susceptibility of asphalt mixtures. In the current study, asphalt mixtures specimens were compacted by gyratory compactor and then were cut into semi-circular specimens. Each of specimens was subjected to water and sodium chloride (NaCl), calcium chloride (CaCl2), calcium magnesium chloride (CMA) and potassium acetate (KA) solutions. Fracture toughness of specimens was measured at three temperatures of 0, -10 and -20 °C using semi-circular bending (SCB) specimen test. Tests results showed that the effects of deicing materials on fracture toughness of asphalt mixture specimens were different at three temperatures. At the temperature of 0 °C, the destructive effect of deicing materials on the fracture toughness of the asphalt mixtures was not observed, while at the temperatures of -10 °C or -20 °C, some of deicing materials could decrease the fracture toughness of the asphalt mixtures. Meanwhile the moisture susceptibility tests results indicated that the deicing materials had no destructive effect on the moisture susceptibility of the asphalt mixtures.        

The low level of safety of transportation causes expanding social and economic consequences. It's also an obstacle to sustainable development. The pedestrian safety is one of the most important issues in the safety of transportation. Non-signalized intersections are one of the places in which there is too much risk for pedestrians because there are rarely any control equipment for pedestrians and vehicles movements. Therefore many conflicts between these two parties occur at such a place. Many effective variables on the intensity of conflicts have been identified, but many of them have been analyzed in signalized intersections and special types of movements like left-turn or right-turn. In this research, the effects of the type of movements (left-turn, right-turn or straight) on pedestrian safety at non-signalized intersections are analyzed using surrogate safety measures. The data have been obtained, using the image processing method. The effects of types of movement on Time to Collision (TTC), Gap Time (GT) and the Post Encroachment Time (PET) have been analyzed by one way ANOVA. The intersection is called Vesal Shirazi-Bozorgmeg Street. Finally, after analysis, it was realized that the type of vehicle movement is significant in only PET in the 95 percent of reliability. The significant difference exists between straight and right-turn movements. This difference was around 0.08 for the logarithm of PET. This measure was smaller in straight movements in comparison with right-turn movements because the speed of vehicles which move straight was more than right-turn ones and there was an indirect relation between the vehicle speed and PET.  

Soil stabilization as a relatively inexpensive method improves the stability of soil retaining walls and slopes via tensile stress mobilized in reinforcing elements. In this study, to present the most economical design of mechanically stabilized earth wall (MSEW) with metal strip considering the safety factors, the simulation model of the wall behavior was associated with an optimization algorithm. In the current research, using Multi-Verse Optimizer (MVO) together with Federal Highway Administration (FHWA) design method, construction cost of MSEW with metal strip was optimized. It is found that using this method, construction costs of a short wall can be reduced up to 22 percent and those of a taller wall can be reduced up to 8 percent in contrast to FHWA method. In addition, sensitivity analysis indicated that the total construction cost of the wall is mostly affected by the cost of metal elements in comparison with soil backfilling costs such that by increasing the metal elements and soil backfilling costs to 5 times more, the wall construction cost increases to about 4.5 and 1.5 times more, respectively. Also, at the end, the tendency of the total cost to the variations of different decision variables such as vertical and horizontal spacing, length, width and thickness of reinforcing elements was evaluated.  

Today, urban railroads play a key role in the public transport of large cities, as this type of transportation system has a higher transport capacity and efficiency compared to other conventional public transportation modes. In this research, a two-objective optimization model is presented by integrating the re-scheduling approach and the stop-skip pattern in passenger traffic conditions after the end of the disruption. This model simulates the flow of passengers according to the timetable based on the time-dependent arrival time of the passengers. Due to the complexity of the re-scheduling problem, a decomposition algorithm was presented for producing near-optimal solutions. Validation of the
re-scheduling model was carried out using numerical tests based on operational data from Tehran and Beijing railways. Based on the results of the re-scheduling model, by increasing the total travel time of trains by less than 1%, the passenger overcrowding in line 5 of Tehran's urban railway could be reduced by about 35%. Regarding the need for a fast response after disruption, the re-scheduling algorithm is efficient. Experimental results show that even in large-scale test problems, the solution approach has a good quality response and computational time, which indicates its effectiveness in re-planning the trains of urban railways.    

In this research, in order to study the effect of using PET on the performance of asphalt concrete containing rubber modified and unmodified binder, PET particles were added into the mixtures in different dosages of 0, 2, 4, 6, 8 and 10% (by the weight of binder). After determination of the optimum binder content of the mixtures, the specimens were made and subjected to Marshall, indirect tensile and dynamic creep tests. The dynamic creep tests were performed using a universal testing machine (UTM-10) by applying a vertical stress of 300kPa at a temperature of 40°C, to investigate the resistance against permanent deformation. Results show that adding PET into the mixtures improves the Marshall stability and Marshall Quotient compared with those for the control mixture. However, the trend of variation with PET content is different for the unmodified and rubber modified mixtures. While the Marshall stability and Marshall quotient increase with increasing PET content in the rubber modified asphalt concrete, they reach to the highest value by adding 4% of PET into the unmodified mixture, and after that they decrease with increase of PET content. The indirect tensile test results show that the indirect tensile strength (ITS) of the mixtures made by rubber modified and unmodified binder and containing air voids content within 6.5 to 7.5%, reaches to its highest value by adding 2% of PET. However, for the mixtures containing air voids content within 3-5% ITS decreases with increasing PET content. Dynamic creep tests reveal that the resistance against permanent deformation decreases with increasing PET content in both mixtures, with a lower reduction in the mixtures made by rubber modified binder. Comparing the results of Marshall Quotient and dynamic creep tests show that the deformation behavior of PET modified mixtures is different under static and dynamic loading. While, the mixtures resistance against deformation under static loading is improved, under dynamic loading they show less resistance than the control mixtures. Also, results of this research show that PET is less effective on the rubber modified mixtures than the unmodified mixtures.  

Pantograph is one of the most important equipment of Electric trains which transferred power from the Catenary to train. Permanent connection of pantograph to the catenary is necessary under all circumstances. On the other hand, the catenary parameters have uncertainly and are variable in a span. This feature challenged the pantograph control issue especially in high speed trains. Maintaining the contact force between pantograph and catenary system under these uncertainties is the aim of this article. So, the dynamic equation of a 2 Degrees of Freedom (2-DOF) pantograph-catenary system is derived and a PID controller is designed, firstly. The Overshoot, Undershoot and oscillations are high in contact force under PID controller, because there are uncertainties in catenary parameters. For reducing the uncertainties effects, the PID parameters are tuned by gain scheduling method. For achieve to better responses, the fuzzy logic is combined to gain scheduling method and the PID parameters updated online using this fuzzy gain scheduling method. Finally, the performance of three controllers on pantograph-catenary system is simulated and analyzed under practical situations. The results show that the combination of fuzzy logic with gain scheduling method lead to improved performance of PID controller for pantograph-catenary system.    

In this study asphalt pavement design and modeling were investigated by AASHTO and SHELL methods which are under the circumstances of Iran (traffic, road condition and climate). The inputs of the modeling are mechanical properties (such as density, modulus of elasticity, effective resilient modulus, friction angle, etc.), specifications of axle loads (loads on pavements) and climate conditions. A finite element software ABAQUS 6-10 was used in this study. After comparing the results of the modeling and design methods, it was found that pavement layer thicknesses obtained by the AASHTO method which chooses thinner layer of asphalt are more economical and optimal than SHELL method.