Journal of Transportation Engineering
Year:2019 | Volume:10 | Issue:2 (39) |Papers Count:12

All bridges designed by kind of structure and built by any type of materials، get burnt out sooner or later. These exhaustions are spread due to several factors such as atmospheric conditions، flood or earthquakes، increased over load more than expected in design phase، design and execution quality، and the type of materials affecting that causes to decrease bridge's useful life if these factors will be ignored. Therefore، bridge maintenance makes to increase its useful life if it happens on time. In this paper، Mazandaran province bridges are studied based on failure situation، faults of each bridges، their condition against traffic load and other effective variables. in order to solve the problem، first، required data have been collected by field study after bridges inspection and then bridges are prioritized based on fault evaluation criteria by Analytic Hierarchy Process (AHP) multi attribute decision making method. Finally، corrective actions are determined based on budget level for bridges. To achieve this goal، a linear mathematical programming model firstly presented and then to solve the large scale problem a genetic algorithm has been developed to find the optimal corrective actions. The proposed algorithm is implemented in MATLAB software and results show that the proposed genetic algorithm have suitable performance to solve the problem. Several budget levels have been considered to assess proposed genetic algorithm validation and changing trend of corrective actions number has been studied. It is seen that amount of effectiveness and total number of repairs are increased by soaring budget level

Intersections as nodes of the transport's network enter maximum delay to users. When arterial intersections are located close together، their performances will be strongly affected by each other. For this reason، the relationships between adjacent intersections timing schemes affect their overall capacity. In this study، the effects of the implementation of coordinated control by bandwith method for consecutive intersections were studied. For this purpose، two networks of intersections which are operated under intelligent control center were selected for the main model as well as validation model. Obtained data from field survey was entered to simulation software Synchro and intersections were modeled in the software in order to define different scenarios and achieve results and outputs. According to the results in a oversaturated conditions which was in peak hour، optimization through coordinated intersections control improved the performance indicators such as delay by 10 %، total stop by 6 %، average speed by 12 %، travel time by 8 %، fuel consumption by 7 % as well as queue length by 25 %. Moreover، in the framework of research the effects of modeling local and User access، adjacent parking، the implementation lagging phase، the output of microscopic software and evaluation of all the states mentioned have been discussed during off-peak period. Model reliability and outputs was confirmed through validation.

Urban street network modeling is known as one of the most important applications of GIS in the field of crisis management. The main objective of this research is to development of an urban smart network based on open street map (OSM) data، which can be used for crisis management. For this goal، after the collecting OSM data، the errors and miscalculations of this data were removed and data certainty was discovered to checking the quality of data. The roads network database of Tabriz municipal were developed for GIS based network analysis. In the following step، location of the Abresan subway station was compared with the optimal access road of assistance centers. For this purpose، we generated a spatial database، which including the fire station location، emergency medical centers، hospital، also information of municipal passage networks data. In addition the expressive data which associated with the route networks، legal speed of movement، direction of movement، the degree of crossover، the intersection in form of network analysis were also taken in account. The results indicated that the OSM data represent suitable functionality and high accuracy for developing urban smart networks، also according to the results the Abresan subway station is located in suitable and accessible area to assistance centers. Finally، the network distance of the nearest fire station and emergency medicine from the Abresan subway station were 2253 and 988 meters، respectively. The nearest distance of hospital from Abresan station is measured to be 1308 meters. The time accessibility for the passage of these paths for fire centers، emergency medical and hospital were 3، 2، and 1 minutes، respectively. According to results، we conclude that the results of this study are in total agreement with the national and worldwide standards.

This paper evaluates different MLPs (multi-layer perceptron neural networks) whilst considering 23 pedestrian injury accident parameters (in four categories) for time period of 3 years (1391-1393). The data belongs to the city of Mashhad in Iran. For this purpose، after preparing required raster layers in GIS، the influence of each parameter has been assessed through evaluation of different structures of MLP. It is worth noting that in the most works undertaken، the vector based modeling has been considered to determine the effect of spatial parameters; and the flexibility and the accuracy of raster-based prediction has been neglected. In the present study، authors have considered demographic characteristics and urban form factors in addition to the common variables in the simulation of pedestrian injury accidents. Furthermore، a total of 38 independent variables in four classes have been assessed. At first، the input raster data with the pixel size of 20 meters were created by employing geo_statistical processing in GIS and then MLPs algorithms have been programed using MATLAB language. A set of raster data containing 111، 537 pixels has been analyzed using MLP changing the neurons، the layers، the transfer functions، the training functions and different combination of training and testing sets. Performance of 25 different neural network structures were validated by MSE and R-squared. The results indicate that a model with three-layer، 70 neurons، the RADBAS transfer function and Levenberg_Marquardt training function (= 0. 95 and MSE = 0. 0020) has the most efficient and optimum design for representing the relationship among the number of pedestrian injury accidents and the effective input parameters. By implementing this model to the study area of the city of، it was revealed that the residential density، the street network and the first level of social status characteristics have the highest impact on the pedestrian crashes. However، the sidewalks having more than 10 meters width، the fourth type of road and the second level of social status have the least impacts.

The rapid growth of metropolises in the world and the increase in their population have engendered a lot of problems such as traffic challenges and disruptions in the urban transportation system. Therefore، the mentioned problems have been basic challenges facing urban planning in late 20th century which have had negative influences on achieving aims of urban sustainable development. The rapid increase in the number of motorized means of transportation، especially automobiles as well as high use of them in cities of Iran and particularly in Metropolis of Ahvaz with the population growth and its unbridled expansion، increasing immigrations and the lack of scientific and comprehensive planning، frequent problems in the public transportation have caused problems such as severe environmental pollutions، high and boring congestion of traffic، citizens’ waste of time، energy overconsumption، unsafety of paths and accidents، etc. have made lives in this city difficult and reduced welfare and convenience in it. Accordingly، the present study aims to identify and prioritize strategies bus service development in Ahvaz Metropolis. The main approach of the study is developmental-applied، the research method consists of descriptive، analytical، and survey research techniques. According to the model of SWOT situation analysis (strengths، weaknesses، opportunities، and threats)، identification and evaluation of the status quo was conducted and after that، with regard to the identified criteria، the four strategies were developed. Finally، using multivariate decision making technique of FDEMATEL، strategies were prioritized. The results of the study indicate that strategies (1) the necessities and commitments of the government to provide required funding in line with the law of development of public transit and fuel consumption management; (2) providing required grounds for facilitating the implementation of integrated urban management; (3) defining Income-generating projects aimed at empowering organizations to increase revenue and create alternative income sources and methods in the municipality rather than increasing sales density، etc.; (4) practicing management of integrated transport and traffic (management of urban travel، management of parking management fleet and public transportation network، managing the culture of traffic management in urban planning، management of emergencies، network management and traffic management on standardization، installation and maintenance of traffic; automated traffic management، traffic engineering management، management of R & D); (5)understanding the interaction of transportation with various aspects of society (economic، social and environmental) and the balance between these aspects in order to achieve sustainable transport; and (6) development of Intelligent Transportation Systems (ITS) are respectively the most prioritized strategies in planning and development of Bus Transit Development in Metropolis of Ahvaz

Using Data Mining techniques، the committed violations by Tehran Bus Company have been analyzed and consequently the hidden knowledge among data has been discovered in this research. First، the data from committed violations by Tehran Bus Company within 2012 to 2015 have been gathered and made ready for the program. The next stage is to extract knowledge through the algorithms of Association Rules and Decision Tree. Identifying the companies with poor performance and high rate of violations and considering the obvious correlation between them in different seasons are among the noteworthy results which are the outputs of the above-mentioned algorithms. The chief managers of organizations should use the Decision Support Systems (DSS) to make decisions in case of uncertainty. The results of the research help managers make decisions about achieving the ultimate organizational goal which is the satisfaction of people. Finding the root of the violations and determining the frequent seasons and months in which the violations are committed can be the cause of instructions and procedures which obligate contractors to precise implementation of regulations، decrease of committed violations and on the whole، improvement in Bus Company. It is a fact، attention to customer satisfaction as a significant and effective factor is essential for achieving stable and sustainable states in all production and industrial units and services firms such as research case study.

Analysis of road pavements responses such displacements، strains and stresses resulting from imposed impulsive loads، is one of the most important issues in pavement design. Various methods such as finite element، boundary element etc. can be used for analysis of this problem، but، as in all matters، the main goal is to reach high accuracy while spending less time for analysis، in this research، a new method of differential quadrature method (DQM) is used. In most studies implemented to date، the behavior of flexible pavement is considered as an elastic material but the asphalt concrte (AC) layer on top of the flexible pavement، behave as a viscoelastic material. The theory of viscoelasticity is an old subject، but its application in flexible pavement modeling، due to the time-dependent behavior of the viscoelastic materials and also the layered structure of flexible pavement، complicates the modeling. In this paper، first، with incremental integration of Boltzmann's correspondence principle and using the generalized Wiechert model for viscoelastic behavior، incremental equilibrium equations of 3D axisymmetric condition are obtained and discritized in spatial domains using DQM. Then، in order to verificate، three-dimensional multilayered viscoelastic problems are modeled using Differential Quadrature Element method (DQEM)، and the results of this method are compared with analytical solutions and finite element method (ABAQUS software) results. In the end، a flexible pavement structure with viscoelastic behavior under sinusoidal loading is simulated quasi-statically، and the effects of the viscoelastic response of the pavement under loading with different speed of vehicles as well as several performance indicators such as tensile stress and tensile strain under the AC layer، vertical stress on the subgrade، and vertical displacement of the pavement surface، which are commonly used in the design of the pavement، are investigated.

In the real-world، cargos may be forced along their routes pass from more number of hubs that this fact in the distribution networks and postal networks are visible. In this case، the use of hierarchical hub location models to determine the optimal location of hubs and assigning the nodes to them seems to be necessary. On the other hand، one of the most important issues in the transportation networks، is timely delivery of goods and increase service levels to enhance customer satisfaction. For this purpose، a multi-modal transportation network has been designed. In this type of networks، it can be used from various transport modes road، rail، sea and air. In the multi-modal transport network، a mismatch between the rate of flow entrance to hubs with processing rates of hub sources as well as time diversity in different modes of transferring goods، causing queues at hubs. Therefore، in this study، it is paid to surveying effects of resource constraints and the diversification in different transport routes time under the requirements of service time by using the queue model GI /G/1. In this study، a new variable neighborhood search-simulated annealing is proposed to solve the problem. Then، several numerical examples and sensitivity analysis to validate the performance of the model and the proposed algorithm is investigated.

Fast and updated access to the information related to urban roads network is one of the requirements with various applications in the field of transportation. Accordingly، the present study tries to evaluate geometric similarities between volunteered geographical information through comparing them with the official dataset، in order to provide the researchers with more assured alternatives. To do so، a new solution is provided، which while identifying the corresponding features in volunteered geographical information dataset and official dataset، compares these features to each other in terms of length، distance، orientation، buffer overlapped area، complexity، size، and sinuosity. For this reason، District 6 of Tehran was selected as case of the study and the 1: 2000 dataset (prepared by National Cartographic Center) was selected as the official dataset. The results were indicative of a 78% mean spatial similarity between the features in Open Street Map (OSM) dataset (a sample of volunteered geographical information) and those in the official dataset. Also، in order to evaluate improvement of geometric accuracy in volunteered geographic information dataset، urban roads networks were studied in years 2014-2017. The results showed that while public participation in creating the features has increased by 27. 8%، the mean spatial similarity has also improved to 5. 77%. Therefore، the researchers can use volunteered geographical information dataset as an alternative for the official dataset in many of the transportation related applications.

To implement asphalt roads in an area، in many cases، especially in poor and swampy areas، there is a need for improvement. In recent years، the use of reinforced soil is common for the design of roads، foundations and retaining walls. On the other hand، the solid waste management، in terms of large volume and longtime decomposition of wastes such as sack polypropylene fibers، in addition to its effective role in the economic cycle is as one of the important indicators of development at the macro level in developing countries. Therefore، reinforcing of soil with the use of waste materials has a particular importance. In this research، by performing a laboratory experiment، the effect of adding various percentages of sack polypropylene fibers on the behavior and values of strength parameters of non-cemented and cemented sand (with three weight ratios of 3، 5 and 7% and 7-day treatment time) were investigated. The results show that the presence of these fibers has a significant effect on the behavior of non-cemented and cemented sand. Adding these fibers improves the strength parameters (φ and C)، increase the maximum strength، failure strain and residual strength of soil. The effect of these fibers on the all studied parameters in non-cemented soil is higher than that of cemented soil. Also، their effect becomes less by increasing the percentage of cement in cemented soil. According to the research، these materials can be used in the road beds، which has environmental benefits، in addition to economic benefits.

In this study، the role of both SBS and Proplast fiber additives in improving the performance of SMA in confronting the rutting phenomenon has been investigated. Using Stone Mastic asphalt mixtures can play a considerable role in reducing persistent and plastic deformation caused by rutting. To perform the experiments، 84 Marshall samples and 8 samples in the slab form were prepared in 4 types. In order to determine the optimum asphalt content، the Marshall design method was used and additives، with extensive studies in the literature، were selected as 5% SBS and 0. 6% Proplast fibers. Then marshall stability to flow ratio، bitumin draindown from the mix and determining rutting percentage using French method، tests were conducted and then these materials were added to the stone mastic asphalt mix، individually and simultaneously. The results showed that samples containing SBS only or containing both SBS and Proplast fibers simultaneously، has better endurance comparing to samples without additives. They showed an increase of about 10 percent in endurance and also the lowest rutting percentages among all the samples as well، while samples without additives showed the highest rutting percentage among all the samples. Regarding to the results of the experiments، using SBS and Proplast fibers simultaneously leads to a reduction in rutting percentage to around half، comparing to samples without additives. Finally، based on the results of this study it can be concluded that the use of both SBS and Proplast fibers in the SMA، can not only improve the physical characteristics of this type of asphalt، but also can have a significant role in dealing with the rutting phenomenon and so can be considered as a good choice for hot areas with heavy traffic loads.

In real life situations، in addition to the variable cost، there is another cost incurred for opening each route، which is known as fixed cost. This problem as the fixed-charge transportation has attracted considerable attention in an industry and business. In recent years، a certain type of a fixed charge is presented as step fixed-charge. Few studies have been done concerning a step fixed-charge transportation problem (SFCTP) that only include single level distribution of a single commodity، in which there is only one kind of a vehicle. In this paper، the capacitated، solid، two-stage SFCTP is modeled. Because this problem is considered to be an NP-hard one، a simulated annealing algorithm (SA) is proposed to solve the new presented model. To evaluate the performance of the SA algorithm، the results are compared to an exact solution obtained by using GAMS. The results show that the SA algorithm provides relatively good solutions in a reasonable time