JOURNAL OF TRANSPORTATION RESEARCH
Year:2016 | Volume:13 | Issue:3 (48)|Papers Count:10

Bridges with each structural shape and with every kind of materials that are made, soon or late, fatigue effects are appeared in them, among kind and rate of these fatigues and their expansion trend, numerous factors are effective such as climate situation, flood or earthquake occurrence, load increase more than design rate, design qualification and performance and kind of materials. If each of these factors are not considered leads to decrease of useful life in structure. In this research after doing investigations by using FMEA-FUZZY method, it became clear that earthquake is known as the main and the most effective factor of bridges ruin in utilization case. For this reason, imposed earthquake on Babolsar bridges was strictly investigated and after bridges modeling in SAP software, probability of ruination in each structural element of bridges was calculated. Then, by using FMEA-FUZZY method, rate of risk in each bridge against earthquake becomes clear. Difference of presented procedure in this research with previous research is that by using this procedure it is possible to correct the situation of all bridges by budget similar to previous cases. And reaching to relatively proper case, while in previous researches, by using multi-criterion decision making method, we only selected a bridge as a critical bridge that was in most critical case and all budget was spend first for this bridge and then was spend for other bridges. The results show that each of bridges in which parameters has debility. So, it is necessary to do all schemes for resisting these bridges against earthquake and to prevent from probable difficulties, caused by earthquake on these bridges. Finally the result show that steel legs buckling at the first bridge and the second is necessary for reform.

Geogrid is made of a polymer and as a stiffener layer in soil to be used and increase capacity and reduce lateral displacement of the wall and the sill settelment follow. In recent years, put bridge deck by a strip foundation on the abutment was used as a efficient method of building bridges has been was introduced. with this method besides being economical and high-speed performance, bump due sill dissimilar between abutment and pile foundations will be eliminated. studies show increase geogrid width to reduce the lateral displacement of the wall is effective. in this paper influence pressure and width sill on the optimal width of geogrid was investigated. also with considering the maximum allowable displacement of the wall sort appropriate geogrid was investigated until the most economical mode that provide stable and displacement of the wall does not exceed the limit set by the regulation is achieved. depth placement the first geogrid under sill in reduction settlement sill is effective so with placement gegrid at different depths the optimum depth is research. in this study 3D analysis by software Abaqus-V6.11-1 with Cap plasticity models done.

Ground facilities are an integral part of the airport, which the most important of them is runway pavements. One of the difficulties and the inevitable failure of the pavement are cracking. Cracking in flexible pavements is a distress seen in the most flight zones. Therefore, it is important to take action to reduce the speed of its spread. In this study, field data of Kerman airport (Iran) were used to achieve the mentioned goal and to adapt the results to the reality. Also, the real values of the thickness and density of the layers and other layer properties obtained from the experiments were used. By using finite element software for runway pavement, a crack was modeled and then its output was used to analyze the pavement in different modes. At first, by loads displacement to the position of the cracking, the place where loading causes the highest stress to the cracking was determined. Next, the different analysis in the targeted area was conducted to investigate the effect of the asphalt thickness changes, crack length changes and the temperature changes in the cracking behavior. The results of change in the crack length showed the stress intensity factor KI increase to 17% with increasing the crack length two times. The amount of stress intensity factor decreases with increasing the asphalt thickness. In other words, the crack growth rates decrease with increasing the asphalt thickness. The results showed that for each degree increase in temperature, the stress reduces by 3%, which reflects the importance of temperature parameter. It is recommended at the temperatures close to zero degrees or below zero, the number of flights to be limited.

Due to the limitation of natural resources and road construction developments, the demand for using waste and recycled materials has significantly increased. Coal waste is a by-product of the coal washing plant and its accumulation leads to different environmental and economic complications. The main objective of the current paper is to compare using coal waste powder and ash as filler in hot mix asphalt with other usual pozzolanic fillers. In the first section of this study coal waste completely replaces the usual fillers with lime stone powder and is compared with the pozzolanic fillers such as cement and zeolite. Mechanical properties studied here include Marshall Stability, Marshall Quotient, flow, tensile strength and moisture sensitivity. In the second section in order to better explore the subject, besides the above-mentioned mechanical properties, the resilient modulus and the fatigue of samples containing coal waste and ash a reanalyzed. The test results from the first section show that using coal waste filler improves the mentioned mechanical properties compared to lime stone powder and zeolite. Moreover, in the second section while coal ash has a better result compared to the raw state but due to difficult procedure, high cost and the pollution resulted from burning, using raw coal waste as a filler in hot mix asphalt is recommended.

Transportation from the beginning of human history has played Key role in shaping human societies and economic development and at present Communicating artery forms the foundation of any country's economy. Sustainable development and Fast and secure transportation as with other aspects of human life When does that systematically and based on the scientific rationale Established. Nowadays, the issue of providing secure access on the road network within the city and suburban is one of the basic principles governing the roads engineering, Traffic and transportation Planning. Lack of safety, especially in the suburban roads would be caused Accidents that usually associated with the death or injury of humans. According to enormous loss of life and property which Road accidents imposes on human societies, Consideration of safety issues as a priority in the transportation management and land use, it is considered a reasonable and acceptable. Roas safty inspection, is a Field study and systematic of road by qualified and competent professionals to enhance quality of road Physical safety and identify problems and deficiencies that may share in reducing the Traffic Safety. In our country, there is no systematic procedure for inspection and a numerical index to compare different parts of roads with each other.in road safety audit in Worldwide, there is procedure known as hazard index For ranking points of two-lane and two-way road that obtained of combined results of road Inspection, Evaluation of road geometrical design And the user's risk exposure. In this article, accident prone sections of the route between the city of Khorramabad and Aleshtar in Lorestan province was investigated And ranked.

Every year we spend a lot of cost for constructing and maintaining roads, these costs are significantly related to the type of the pavement and its fundamental materials. Iranians usually use the flexible pavement which contains the asphaltic overlay and the granular base and sub grade, while we can pay more attention to the rigid and the composite pavement for using in our highways too.In this study a flexible pavement and a composite one for the Qazvin - Zanjan freeway by AASHTO method has designed and their initial costs and whole life costs has compared with each other. It has shown that the cost of constructing composite pavement is more than the flexible one but because of the cost-effective maintenance, its whole life cost is less than the whole life cost of traditional flexible pavement. Also the composite pavement has some technical advantages such as its high fatigue resistance, low deformation and high friction, though, composite systems are potentially more prone to other distresses, such as reflective cracking and rutting within the HMA layer. Premium HMA surfaces and/or reflective cracking mitigation techniques may be required to mitigate these potential problems.