فصلنامه مهندسی حمل و نقل
سال ششم شماره 1 (پیاپی 21، پاییز 1393)

Modified Matrix Subtraction Method (MMSM) and Tensor Method(TM) are simple but useful methods for detecting damage in concrete piers of bridges. In the methods, square time-frequency representation was used for the first time to damage detection in the bridges. In signal procedures, damage diagnosis becomes possible with structural monitoring which sensors are used for measuring the structural behavior. Considering the variety of sensors, in accordance with the used method to detect damage, it is necessary, suitable sensor for measuring structural behavior is determined and sensitivity of the used method to recorded signals is investigated. In this research, exciting force and time-frequency representation algorithm was used to detect damage and determine its location. Besides, analytical models of W180 and MGR bridges were selected as the structural samples. Also sensors including displacement gauge, speedometer and accelerometer for detecting damage in concrete piers of bridges using MMSM and TM were evaluated and optimal signal type which is much compatible with the proposed methods and algorithm were assessed and identified. According to performed calculations, using response signals recorded by displacement gauges and applying MMSM and TM, better results were obtained when compared to speedometer and accelerometer were used. When displacement gauges were used, the damaged piers were correctly identified in all of the cases. However, using signals recorded by speedometer and accelerometer, damaged piers were reported correctly in 88.9% and 94.4% of the cases, respectively. Furthermore, the effects of the distance of the sensor locations from the affected area and their impact on the results were studied. In accordance with the calculated results, by reducing the distance between mounting location of the sensors from the damaged area, ability and accuracy of MMSM and TM were increased.

Nowadays, there are many social and economic costs for transportation related problems. All these have led to improvements in transportation demand management (TDM) approach by transportation ‎policy makers. ‎TDM is a general term focused on more efficient use of transportation resources of societies. According to political considerations and due to high social cost of citizens’ habits change, as well as the cost of upgrading a designed technology to a newer one, TDM policies are often remain persistent for long periods in cities. To reflect the effect of such a TDM policy on transportation pattern of a city, adopted models must be able to estimate their long term effect on the city. This paper is focused on long term effect of simultaneous policy pairs on society and environment through a 20-year imposed cost index. To capture the interaction effect of two policies as well as their long term effect, a system dynamics model is adopted for the city of Mashhad. Three TDM policies consisting of increase in fuel cost, increase in parking cost and cordon pricing are considered, each of which designed in four different levels. Results show that policy pairs including increase in parking cost are more significant towards reducing the 20-year imposed cost index.

Creep is defined as a time-dependent deformation behavior of viscoelastic materials under loading. In this study the creep behavior of asphalt concrete mixture is studied, using creep test by soil consolidation device, which is simple and exists in many laboratories, by the British Standard: BS-598- Part111. The strain-time diagram as a result of the creep test divided into four parts and a strain defined for each one. The four strains include: initial strain, final strain, total and reversible strain. In this paper, two types of aggregate grading, two types of bitumen in three different percentages of bitumen used to prepare laboratory samples. The tests performed in three different temperatures of 20, 40 and 60° C. The results of study showed that the initial and final strains as results of creep tests can illustrate the effects of asphalt concrete mixture characteristics on its rutting behavior. However, the total and reversible strains did not follow the regular trend.

Finding the shortest path that a vehicle can go through its all points with static coordinate, and finally back to the initial point is one kind of vehicle routing problem. This problem is called Traveling Salesman Problem, which has many applications in transportation engineering and other science. Deterministic methods (mathematical) have been shown unsuitable for such complicated problems. Therefore, in this paper it has been tried to solve this problem by modifying Bee Colony Algorithm, one of the recent optimization algorithms. Results demonstrate the proposed Bee Colony Algorithm has suitable ability to solve the problem, compared to other optimization methods.

Nowadays, the rate of urban population growth and urban communications can improve the essentiality of developing airport structures as an important transportation issues. The process of airport development as a complex structure is a time consuming and costly task. Several parameters such as social and economic elements, operational specifications, technical features and security issues have different effects on the performance of this phenomenon. The assessment and identification of flight barriers locations can be considered as one of the most important technical factors in the process issues of airport development. So, accurate methods are required in order to improve operations under the technical development process. In this paper, according to national and international parameters and standards, the criteria of airport development have been declared and prioritized for the future plan of the airport runways. For this purpose, at first, the real condition of each bands in terms of: topography, vegetation, hydrology, wind direction, proximity to urban areas, lighting systems, slope, length of runway and associated spatial layers, are checked in Birjand airport and entered into the GIS environment. The output GIS ready layers are aggregated in a meaningful context by prioritizing bands. After that, TOPSIS multi criteria decision making model is performed in 6 steps. Finally, considering numerical results, a reasonable set of runway directions is defined for the future planning and decision making on the airport. Comparing results of seven runways in Birjand airport indicates that No. 28 (runway) by the rank of 0.66 is the best and No. 08 by the value of 0.24 is the worst alternatives for the future policy of airport decision makers. Also, the east direction is the most appropriate and the south-west direction is the worst options for developing airport bands in the future development of Birjand airport.

In transport route planning, generally one or a few alternative routes are proposed. The process of selecting best route is carried out by considering minimal environmental, social and economic impacts and high performance in technical transportation criteria. This process may fail without considering the cultural, social and economic patterns of the region, suitable programming for public participation and coordination between the different organizations. In addition, lack of sufficient or updated information or lack of similar way to gather data a one of the important problems to get the real results. Therefore, spatial data infrastructure (SDI) is very useful for developing common standards and data sharing mechanism between different organizations in this domain. On the other hand, web 2.0 technologies that enable ordinary people to create and share spatial data facilitate public participation. These data called volunteered geographic information (VGI) can be used for completing and updating official data. The purpose of this paper is design a system by considering evaluating impacts and technical transportation criteria of proposed alternatives for selecting best rote as well as creating an environment for facilitating sharing spatial data and public participation. Also, this system provides a convenient, reliable and faster way to achieve best alternative based on most important criteria by using multi-criteria methods. Results indicate success of SDI in integration with VGI for selecting best route, so that can help to reduce extra costs, to reduce environmental impacts and increase public satisfaction.

The aim of this study is to develop the algorithms for solving train timetabling problems in the double-track railways. To find the optimal solution of the problems, the common software package CPLEX 11 was used in addition to a method based on branch and bound algorithm. Both the mathematical model and branch and bound algorithm were implemented in Java Software and some large-scale real problems were investigated. The problems are based on Bafgh-Sirjan and Tehran-Mashhad railways. Comparison of results show more efficient performance of the algorithm rather than CPLEX. The criterion to compare the performances was the solving time. Five methods were then used based on beam search algorithm to find near-optimal solutions in a rational amount of time. Three of these methods are considered as the innovations of the present research. The results of applying beam search methods demonstrate more impressive proficiency of the heuristic methods innovated compared to methods suggested in previous works especially when facing large-scale problems. Depending on the importance of accuracy and time in different conditions, the excogitated methods can generate the train timetable schedules. By using the results of the research, it is possible to prepare the optimal and near-optimal time-tables especially for the long railways with the large amount of trains.

In order to find the most economical scenario/alternative among the different proposed set of scenarios/alternatives, one approach is to perform an engineering economy evaluation, or stated more precisely, a cost benefit analysis (CBA). Within the conventional CBA context, all the monetizable costs and benefits of each decision alternative are determined and the CBA procedure is put forward by these deterministic and exact values. However, when the costs and benefits embody considerable uncertainties, one needs to leverage an adapted tool to be capable to perform the CBA with such uncertainties. In this regard, Fuzzy set theory could be a promising approach to handle the inherent uncertainties in the economic evaluation of the projects. In this paper, the classical equations of the CBA are extended to the fuzzy environment and according to the economic situation of Iran, the interest rate, inflation rate, exchange rate, and the construction period is considered as the fuzzy variables. Subsequently, the proposed fuzzy-CBA approach is employed for the economic evaluation of the Qom metro system. The fuzzy variables used in this paper are selected according to the specific economic situation of the country that was affected by international sanctions, high inflation rates, and mismanagement of the economy.

Pavement evaluation at Network-level is performed with the aim of assessing conditions of pavements, the required maintenance level (i.e. preventive, rehabilitation or reconstruction) or prioritization purposes. The data required to assess network-level pavement evaluation are fewer than the case of project level evaluation. In addition, less pavement analysis and calculation are required. Asphalt pavement structural condition analysis at network level is generally performed using FWD data for determination of pavement layers moduli and effective Structural Number (SNeff). FWD data analysis requires information regarding pavement thickness. These can be determined using GPR or doing core and pit in pavement. Simplification of the collected data and analysis of FWD data are important issues for rapid assessment of road networks. In this study, ten different methods were evaluated in three different levels of thickness requirement (i.e. no information of pavement thickness, knowing pavement total thickness and having thicknesses of each layer) to determine pavement effective structural number. A field analysis was performed applying FWD on seven pavements having different structural numbers (i.e. having low, medium and high SN values). The above analysis was performed and it was revealed that among the various methods, Jameson with correlation coefficient of 0.71 in the category “no information of pavement thickness”; and Wimsatt with correlation coefficient of 0.92 in the category of “knowing total pavement thickness” showed to better represent pavement condition.

For urban transportation development there are a lot of annual costs, such as fuel importation, roads development, car repairing. Also environmental transportation impacts like energy consumption, noise and air pollution, increase the mentioned costs. Along rapid urban development it has become a considerable concern in the urban environmental management. Therefore, urban transportation is an important area in the field of environment. Hence it is required to pay more attention to environmental management of urban transportation. One of the useful management methods is development of Non-motorized Urban Transportation (bicycling and walking). The overall objective of this study is to develop a GIS model to plan suitable locations for non-motorized urban transportation. Arak, a developing city in Iran has been chosen as a case study. Methodology of this study helps to select suitable sites for development of non-motorized urban transportation. GIS as a powerful tool is applied for layers overlaying and interpretation of several scenarios. The results as the accessibility map and analysis for 3 transportation options (motorized transportation, bicycling and walking), shows high suitability of the study area for development of non-motorized urban transportation. Regarding fuel consumption issue, there are a lot of non-suitable location of main destinations in urban transportation network. This research has successfully managed development of a scientific approach for current and future development. It can be employed in transportation planning and suitability assessment at the local and national structure plan levels.