JOURNAL OF TRANSPORTATION RESEARCH
Year:2009 | Volume:5 | Issue:4 (17)|Papers Count:8

In analyzing the macro economics issues, investing in transportation sector in order to job creation has paramount importance.In this paper, the role of investment on job creation in transportation sector is estimated and analyzed based on dynamic approaches regarding - labor demand and co-integration. For estimating the model, statistical data within the period 1350- 1381 have been be used. Results show that primarily the co-integration models variables are recognized, then structural models and the optimal number of orders will be specified. In the next step, the number of co-integration vectors are determined and finally, the relationship between investment and labors demand in transportation sector are estimated. In order to join the long term balanced relationship among variables withshort term fluctuations, vector error correction model related to balanced relation, will be estimated for variable employment in transportation.Among of different models of labor demand, the best model is "scientific model" which is estimated from the following relationship:LD=a0 + a1 AKt + a2 Kt + a3 PKt + UtLD=shows the number of job applicatorAK= Total number of investmentK= The current amount of investmentPK= Utilization of investmentU= disturbance of timeT=TimeThe results shows that the more labor demand, the more increased investment. Based on this method, if the investment in transportation increased to 1 million, the number of labor demand in transportation sector will be increased only to 19 percent. On the other hand, %19 x1000= 19, means that creating a new job in transportation sector demands 52.63 Million Rail investment. By creating a new job, 621 persons will be employed at new jobs. According to achieved analytical results and based on vector error correction model. the following result may be concluded. The transportation sector having the development strategy regarding two inputs (labor demand and investment) will have no substitutes for the labor demand and there will be no reduction in the manpower.

What has initiated the idea of this research is the situation of marine, rail and road transportations in the south region of Iran, the Persian Gulf and Oman see. There are a few large Iranian ports in the region (e.g. Imam Khomeini and Shahid Rajaee) that have been equipped to serve large containerships while, most of the other ports either have not been developed or their geographical and topological restrictions do not let them to serve large ships. For instance, Abadan and Khorramshahr were two active ports and main Iranian Import/Export terminals until the Iraqi army attacked them in 1981. Although, the war finished in 1989, nowadays these are unable to serve current fleet of large container ships due to the limitation of their water way, the Arvand- River. Therefore, their rail and road transportation systems' capacity are mostly unused. On the other hand, due to the national economic development programs and the especial attention to the Iranian 20 year's economic vision, Iran needs to develop continuously new transportation capacities as well as better utilization of the existing capacities. To develop the transportation capacity, one way is to invest on the existing ports in order to serve larger ships. However, in one hand, the investment should continuously grow because, as the literature shows, mega-ships and rapidships are going to emerge until the year 2020. On the other hand, some of the ports, due to their geographical situation, are not able to catch any share of those investments. Therefore, we need to find a way to activate the small ports to use their capacities.

Efficiency and benefits of seismic isolation as a passive control allow designers to reduce and balance the earthquake forces imposed to bridge piers and abutments. Regarding the variety of bridge damages occurred in the past earthquakes, mostly as a result of underestimation of seismic forces, seismic isolators can be effectively used in designing or retrofitting of bridges in high seismicity zones. Numerous existing bridges in the country use expansion bearings between superstructure and substructure. To mitigate the impact of seismic forces and increase bridge safety during earthquakes, these bearings can be easily replaced with seismic isolators.Although seismic isolation has been used for only two decades, extensive studies conducted in this field altogether confirms the efficiency of seismic isolation in bridges. The objective of this paper is to briefly review seismic isolation and its application in bridges to reduce earthquake forces in order to encourage their use in the country, and to investigate the shortcomings of existing expansion bearings. For this purpose, seismic isolation efficiency of two typical kinds of high-way bridges that are isolated with four elastomeric isolators is investigated by nonlinear earthquake time-history analysis. It is concluded that elastomeric isolators are very effective in reducing seismic forces and displacements of the typical bridges. Changing the vibration nature of the bridges, isolators can decrease the earthquake lateral force level and protect the non-ductile substructure elements through deviating and absorbing a major part of input seismic energy The larger the lateral stiffness of the bridge (like bridges with smaller spans and shorter piers), the more effective the seismic isolation. In addition to reducing seismic responses, seismic isolation, distributes earthquake force equally among piers and abutments. However, by decreasing the elastic stiffness of isolator, bridge responses including lateral drifts and internal forces reduce more, while the absolute displacement of the deck increases. This issue can be compensated by increasing yielding force and damping of the isolators by inserting other types of devices. Elastic stiffness as well as yielding force of isolator by controlling the hysteretic damping are important factors. Moreover, to get familiar with the seismic performance of existing bridges having expansion bearings, and to identify their limited and inadequate application as seismic isolation in bridges, their seismic behavior is studied and restricted use of such bearings for seismic isolation of bridges is numerically investigated. For this purpose, investigated bridges (with or without expansion bearings) are modeled and analyzed with "SAP2000 Nonlinear" subject to different earthquakes. Results show that expansion bearings effectiveness in reduction of seismic responses is not sufficient as seismic isolators. Furthermore, even in case of having enough slip during earthquakes, corresponding damping and energy dissipation of expansion bearings would be small due to their linear elastic behavior for force-displacement relationship. As a result, incapability of expansion bearings in tolerating large shear strains and absorbing input earthquake energy, because of damping shortcoming, reduces their efficiency as seismic isolators. For optimum application of seismic isolation in new bridges and also for retrofitting existing bridges, it is highly recommended to do research on manufacturing elastomeric isolators reinforced with steel plates or fiber polymers to induce high damping and use them instead of typical neoprene expansion bearings.

Improving public transportation services is one of the major factors for enhancing the quality of people's life in today's societies. The quality enhancement of transportation services requires increasing coordination in processing and also providing the people with the easiest and the fastest ways to access the services.Given its potentialities, the e-commerce can be considered as a base for improving and evolving the public transportation processes. Thus the e-commerce adoption by public transportation companies is regarded as a step towards enhancing their processes. This paper regarding the models of e-commerce adoption and their analysis provides a proper model for appraising the performance of the transportation companies in e-commerce adoption. One of the public transportation companies (RAJA), a leading company in e-commerce adoption, has been examined in this paper using the provided model in order to appraise its performance. Questionnaires have been used for data gathering and for analyzing the collected data, Path analysis has been used to set the effects of the model variables on the performance of the company. By analyzing the gathered data, the effective indicators influencing the performance of e-commerce have been identified. Thus, using these indicators, a framework for appraising the performance of the public transportation companies in e-commerce adoption has been provided.

Fatigue cracking is one of the most prominent distresses in asphalt pavement. Considerable research has been done to develop theoretical models, experimental laboratory testing techniques, and data analysis methods to predict the fatigue performance of asphalt paving mixtures. The majority of fatigue studies were conducted in order to determine the curves and relationships that are called the transfer functions.Usually, the transfer functions are given based on the test results conducted in more than 250 micro strains. But in long life pavements, we need to examine the behavior of asphalt mixtures in lower strains. Long life or the perpetual is defined as more than 40 years without any major structural failures or repairs.

Based on the published information by Iranian Bank Markazi (Central Bank of Iran), the share of investment in transportation sector increased from 11.04 to 22.27 percent over the period 1372 (1993) to 1382 (2004). It seems that Iran's transportation sector has been in the duration of capital accumulation. Since the development of this sector is very expense intensive, it is necessary to study how investment in transportation influences the macroeconomic variables. Hence, in this study we investigate the effects of government spending or public investment in transportation on private sector investment and economic growth in Iran. In other words, we respond to the two following questions considering the mentioned period (1993 - 2004): 1- Does public investment in transportation crowd out private sector investment? 2- Is there a positive relationship between public investment in transportation and economic growth?

Cold in-Place recycling (CIR) has been effective at rehabilitating the aged pavements, and many agencies have used asphalt emulsions for CIR in their projects with good results. However, some emulsion CIR projects exhibited rutting, thermal cracking and asphalt stripping problems, leading agencies to use Portland cement, lime and class C fly ash as additives to prevent early rutting and stripping problems. Due to lack of previous studies on applying additives in CIR mixes, in this study we used Portland cement and lime as additives. The Portland cement was introduced in powder form and lime was utilized as hydrated lime in powder form and lime slurry, and the effects of each additive on permanent deformation of CIR mixtures have been evaluated. The objectives of this study were to evaluate the effects of lime and Portland cement on permanent deformation of CIR mixtures with asphalt emulsion and comparing the effects of these two additives. A laboratory study was undertaken to evaluate the effect of Portland cement and lime on permanent deformation of CIR mixes. The mixtures were tested for Marshall Test (ASTM 0 1559), resilient modulus (ASTM D4123), and Dynamic creep test: BS-00226, Wheel track test: BS 598: Part 110: 1996.