پژوهشنامه حمل و نقل
سال چهاردهم شماره 1 (پیاپی 50، بهار 1396)

Speed management is one of the most effective methods for controlling vehicle speeds. Using speed control devices is one of the most important and effective method for preventing speed violations on road. Considering the high cost of intelligent speed control systems, limits on financial budget projects and other restrictions, covering all the road segments by speed control system is uneconomical and almost impossible. Therefore, speed control systems required to be used only where it can have significant effect. In this paper, it is tried to develop a optimization model for maximizing the speed enforcement coverage on road. Various restrictions for locating speed cameras like physical characteristics of the road segment, accident statistics, and traffic volume were considered in optimization process. The Case Study is a part of Karaj-Chalus road from Amir-Kabir square to Gachsar with 60km length. The results were analyzed for different levels of budget.

The Ecological Footprint has emerged as the world’s premier measure of humanity’s demand on nature. This accounting system tracks, on the demand side (Footprint), how much land and water area a human population uses to provide all it takes from nature. This includes the areas for producing the resource it consumes, the space for accommodating its buildings and roads, and the ecosystems for absorbing its waste emissions such as carbon dioxide. One of the most innovative methods to calculate and evaluate the effects of human behavior on the environment and surrounding geography is the method of ecological footprint that popular in recent years has been many of the communities. In this study, we have attempted that estimating the ecological footprint index for the transportation demand of the residents in the provinces of Iran. Moreover, the calculating and comprising the biological capacity and ecological footprint of transportation demand of the residents in the provinces of Iran allowed us to identify biocide provinces. The results show that the biocide areas are most central of Iran and include the provinces of Tehran, Alborz, Qazvin, Qom, Isfahan, Markazi, Zanjan, Hamadan, Ardabil, East Azerbaijan and West Azerbaijan. In other words, obtaining transportation demand of resident’s provinces is with the destruction of the biosphere. But the study the changing of the variables shows that provinces with high per capita production have higher crimes, so the states immolated two important aspects of sustainable urban development, the environment and social, to achieve higher production.

The main purpose of this paper is evaluating the impacts of fly ash additive on mechanical and functional properties of polymer modified stone matrix asphalt (SMA). Fly ash was used as a filler in various percentages as 0%, 2.5%, 5%, 7.5% and 10% by weight of aggregates. In this research to defining mechanical and functional properties of modified asphalt mixture, moisture sensitivity, Marshall stability, resistance to permanent deformation and resilient modulus were carried out on the SMA mixes. The results show that , use of fly ash as a filler has no effect on drain down of the mix and this property just improve by bitumen modifying (by means of fiber or polymer). The results of moisture sensitivity test show that the most positive effect was related to use SBS polymer as a modifier and in samples with 7.5%FA. Also results of dynamic creep test show that, the value of flow number for prepared samples with fiber is significantly lower than polymer modified samples.

Natural disasters are abrupt events and have extended effects on vast areas. Due to these features, decision making and crisis management are complicated tasks. In this situation, hasty decisions may cause immense waste of organizational and national resources and drop in quality of services. This study provides a model to optimize emergency services with regard to two objectives, namely 1) maximizing the total satisfied demand of customers, and 2) minimizing the cost of emergency services (i.e., time or distance). One of the practical assumptions of this problem is using the covering idea to provide the customers demand in case of unavailability of communication paths to the customers. Essentially, the demand of each customer can be satisfied by directly visiting it on a vehicle route or it can be covered by other visited customers located within a given pre-specified distance of it. We propose a node-based mathematical formulation. Moreover, to obtain the Pareto frontier, we present a hybrid bi-objective heuristic algorithm by combining the adaptive large neighborhood search (ALNS) and multi-directional local search (MDLS) algorithms. The performance of the proposed algorithm is tested on a set of 72 randomly generated instances. Computational results indicate the effectiveness of the proposed algorithm.

Airline companies due to the industry's own Hsasyt Hay economic issues such as the high cost of fuel prices, regional wars, and lack of seasonal demand from passengers, political sanctions and terrorism dumped into bankruptcy. In addition to these, the aviation industry, an industry which is considered expensive that owns a major factor in throughput is and difficult to administer these firms to be placed sensitivity. Hence the study of the history of the aviation industry, we have seen many bankruptcies. In the event of bankruptcy of an airline, the airline industry should assess its impact on the two basic elements occur. The passengers to serve as the main consumers of air transportation and airports as infrastructure, aviation Pillars. Assumptions such as that whether travelers are affected by this phenomenon? Whether the airline's bankruptcy effect on contractual relationships with airports and their economic performance. This paper seeks to answer these Assumptions and by demonstrating the impact of the bankruptcy of airline companies on the above, in addition to the emphasis on prevention of bankruptcy of airline companies, on the integrity of these solutions is necessary.

In this study, a new technique for monitoring the structural health of bridge piers, in point of view of earthquake induced damages, was introduced and then it was simulated and evaluated by the use of a scaled model of a typical bridge. This system use the detection of phase difference between two synchronous receiver nodes connected through a wireless sensor network, and is based on using an array of inexpensive high-frequency oscillator circuits (4 GHz) as wireless transmitters through placing them in the important structural positions of the bridge piers, and then receiving and analyzing the signals sent by these transmitters by two synchronous receiver nodes. The proposed monitoring system measures the changes in phase difference between two synchronous receiver nodes before and after damage (displacement or deformation); it showed an accuracy of a tenth of a millimeter in the simulations, and it also has a high reliability in monitoring the structural heath of bridge because it provides a real-time report of status of each transmitter (activated, deactivated, damaged). The proposed system has a low price compared to other SHM methods and also has a much lower volume and complexity of data processing compared with similar techniques. This study did not had any field trial, but a complete simulation by the use of an array of six transmitters (TX) and two receivers (RX) was conducted for a scaled model with six piers, and mathematical and geometrical principles and signal processing and simulation details was thoroughly examined.

Identifying Stop and go traffic results in traffic oscillation on freeway. because of scarce vehicle trajectories data and aggregated sensor data not only identifying stop and go traffic still limits but also our understanding of this type of the oscillations in congested traffic is still limited. In this paper, analyzing stop and go traffic based on trajectory data of NGSIM presents car following model that not only is able to reproduce the spontaneous formation and ensuing propagation of stop and-go waves in congested traffic, but also based on a behavioral car following model studies microscopic traffic hysteresis from a behavioral perspective. The statistical analysis of the model’s parameters reveals that there is a strong correlation between driver behaviors before and during the oscillation, and that this correlation should not be ignored if one is interested in microscopic output. Also, statistical results of traffic hysteresis based on driver asymmetric behavior reveals that generation and type of traffic hysteresis patterns depending on driver behavior of position along the oscillation. In other word, when driver meets traffic oscillation and deceleration wave starts, traffic hysteresis depends on driver behavioral of patterns and group and scenarios inside the different stages of an oscillation generation.

The objective of this research study was to investigate and evaluate effects of bentonite on fatigue properties of hot mix asphalt (HMA) mixtures. The experimental program for this study included use of five percentages of bentonite (10%, 15%, 20%, 25% and 30%) by weight of bitumen for modifying base bitumen. Several tests such as: marshal stability, indirect tensile strength, resilient modulus and fatigue test were conducted. The fatigue tests were based on four-point bending test in strain controlled mode at 3microstrain levels (600-800-1000lm/m) with sinusoidal loading. The fatigue lives of mixtures have been evaluated based on the 50% reduction of the initial stiffness modulus. The results show that fatigue life of asphalt mixtures prepared with bentonite modified bitumen is longer than conventional HMAs.Also, bentonite leads to relative increase in indirect tensile strength and resilient modulus asphalt mixtures.Finally, based on experimental results, a model is proposed to describe the fatigue behavior of asphalt mixtures containing bentonite modified bitumen.

Demand for Maritime transportation is derived from International transactions between countries. Hence, in this research in addition to Scrapping tanker price, freight rate determinants such as new-building and second-hand tanker price, the role of seaborne trade is considered. To study the tanker market, we used data between 1987 and 2010, extracted from the Clarkson Research Studies. As causality was not predetermined, in order to discover a co-integration relation and causality direction, a VAR and VECM is applied following appropriate Unit root tests. According to results, unlike short run dynamics, new-building and second-hand tanker price and seaborne trade volume have affected freight rate in long run. Moreover, in short run, freight rate, seaborne trade volume and second-hand tanker price affect new-building price. Finally, the increase in seaborne trade volume, after one period adjustment, tends to increase in freight rate. This impact is temporary.

Based on definitions, skid resistance means the preventive and resistant force which is made by interaction between pavement and the lock wheel. The stone matrix asphalts (SMA) are the warm asphalts mixture which have high strength against skid because the existence of more percentage of coarse aggregate. With consideration of the importance of using the mixtures of SMA as a covering layer which is resistant against skid, and recently particular consideration about using these kinds of mixtures in Iran, so in this research for the evaluation of skid resistance of these kinds of mixtures, the influence of various parameters of asphalt mixtures assessed, such as the amount of bitumen, the kind of aggregate, graduation and the nominal maximum aggregate size (NMAS) and the shape of coarse aggregate in skid resistance of stone matrix asphalt (SMA). Respectively, the influence of microtexture and macrotexture of asphalt specimens was done with the British pendulum tester and sand patch method. From four kinds of lime aggregate, silica aggregate, steel slag and recycling aggregate from the asphalt pavements, and also one kind of bitumen (60/70) with the fiber of rock wool, were used in construction of asphalt specimens of SMA. The mixtures of SMA have four kinds of graduation with nominal maximum size of 19, 12.5, 9.5 and 4.75 mm. The way of design of mixtures of SMA, was used based on the way of proposed in the 425 report which is related to the project of NCHRP9-8. The results of this research showed that the slag aggregates have the better performance in skid resistance than other aggregates. And also the skid resistance of asphalt specimens of SMA has the direct relationship with the increase of the amount of nominal maximum aggregate size (NMAS) and one thing which should be mentioned is that cubic aggregates have 5 to 10 percent more skid resistance than elongate and flaky aggregates.

Designing the suspension systems has been investigated as a major challenge to eliminate the undesired effects in the vehicles. Dynamic analysis of a nonlinear six degree of freedom (DOF) suspension is investigated in the present paper. Dynamic equation of motions of the wagon which is consisted of the wagon main body and two bogies were obtained using Lagrange method and then the primary resonance mode frequency response equation under external excitation is derived by solving nonlinear equations through multiple time scale method considering six DOF for wagon vertical movement. A dynamic vibration absorber system is used to passively control and minimizing the primary resonance vibrations of nonlinear system. The frequency response equations of the system were then compared either with or without dynamic absorber. Using a genetic algorithm, which is based on a random driven process, the best performance of the dynamic absorber suspension of the wagon in a six DOF system is investigated. During the process of solving nonlinear equations and optimization, a harmonic input with very small amplitude was assumed as input exerted on one of the wheels.

System management and maintenance procedures asphalt pavement assess the current situation and predict their future according to the parameters affecting them. For this purpose, after completion of data collection models to predict the PCI index using the Marshall test results for Region 2 in Tehran have been developed. To estimate the PCI, the percentage of bitumen, Marshall Resistance, passing traffic and pavement age based on appropriate statistical tests and SPSS software were selected as the independent variable. Two separate methods were used for modeling, The first way is through the process of regression using SPSS software for analyzing the effect of each of the variables on the model output (sensitivity analysis) was used the results of the sensitivity analysis shows that the strength of the Marshall greatest impact directly on the index PCI. PSO algorithms and genetic algorithms to optimize the use and the optimal amount of each of the independent variables were obtained for the maximum index PCI.

Almost all of seismic design codes for building systems accept heavy damages to buildings, in case of large earthquakes, although they don’t accept the building’s collapse. Nevertheless, past earthquakes have shown that level of the accepted damage may be so high that demolishing and reconstruction of the building becomes inevitable. This, in turn, results in some unacceptable consequences in large populated cities, such as thousands of homeless and/or jobless people for a very long time, very time consuming, difficult, and costly demolishing and debris removal processes, and finally very massive, and therefore, costly and time consuming required reconstruction works. Regarding these facts, any idea which can lead to creation of repairable buildings is greatly acknowledgeable. One such idea is ‘Directed-Damage Design’ (DDD) idea, which means guiding the damage to some pre-decided parts of the structural system, so that other parts do not experience any major plastic deformation, and therefore, making the building easily repairable only by replacing the damaged elements. Design of repairable buildings, have been paid great attention by some researchers in recent decade. Use of rocking mechanism of the building’s structure (Azuhata et al. 2004) and employing telescopic columns in buildings with rocking/seesaw motion (Hosseini and Noroozinejad Farsangi 2012, Hosseini and Alavi 2014) are some samples of these researches. In previous researches, yielding base plates, yielding bolts, conventional and adaptive viscous dampers, friction dampers and some other devices have been used for energy dissipation. To use the DDD idea for creation of repairable steel buildings with square plan, in this study, a structural system having the capability of seesaw motion with respect to a central massive support has been considered in which the bottom ends of the all circumferential columns at the lowest story have been equipped with Double-ADAS (DADAS) dampers, which dissipate a great portion of the seismic input energy. The hysteretic behavior of DADAS dampers has been investigated by using finite element analysis. Seesaw motion of the structural system can make it possible to concentrate the damages in DADAS dampers at the base level of the building. At first a set of regular steel multistory buildings with 5, 8, 11 and 14 stories have been designed based on the conventional code provisions. Then, the structures of the designed buildings have been changed into the structure with seesaw motion by using, at the base level of the building, a massive central column, eliminating other middle columns, and equipping circumferential columns with DADAS dampers. To show the efficiency of the proposed structural system and dampers, a series of nonlinear time history analysis (NLTHA) have been performed by using a set of 3-component accelerograms of some selected earthquakes. Numerical results of NLTHA show that the proposed seesaw structures can efficiently decrease the seismic damage in the building, so that plastic deformation happens only in DADAS energy dissipaters, and the main structural elements remain basically elastic, and therefore, the buildings designed and constructed by the proposed technique can be easily repaired even after major earthquakes.

With entering container into transportation area, this area experienced a huge change; however, the imbalance problem between input and output container in ports has been standing until now. This imbalance between import and export has made a problem called Empty Container, as the import and export ports are facing surplus and shortage of empty container. In this paper, to solve the desired problem, the empty containers transportation planning model with two goals, minimizing total costs including transportation, storage, shortage, loading and unloading cost of empty containers, and maximizing availability of empty container formulated by minimizing sum of the maximum shortage of empty containers at the export ports in all periods, has been developed. Then the proposed model was linearized, and with using weighting method was converted to a single objective of the minimizing costs. Finally, to verify the proposed model, a numerical example by considering a time-space network of Iranian maritime ports has been solved applying the Lp-metrics method, using GAMs software. The computational results indicates the efficiency of the proposed model in making the problem balance, reducing the total cost with 66% compared to the real world, and optimality of set targets.