فصلنامه جاده
سال بیست و چهارم شماره 2 (پیاپی 87، تابستان 1395)

Manhole covers are one of the basic needs for a city which are used to protect our underground facilities from external dangers and also protect our citizens from the probable hazards related to these facilities. These covers are located in paths like sidewalks and streets in a city. Their presence in such places may create specific problems and hazards, which ignoring them and not trying to solve or prevent such hazards, may result in monetary loss and citizens’ injury or death in some cases. Some of these problems come from the cover itself, such as noisy manhole covers or cover’s removal because of inappropriate installation. Some others are related to the facilities, like the bad smell coming from sewer manholes or explosion in a manhole because of intolerable pressure coming from the gases and vapors resulting cover’s shooting out to the street or sidewalk. There are also some problems which are made because of an external matter like iron covers being stolen and a deep hole remains which is a great danger for a pedestrian or cyclist. In this paper we’ve tried to describe covers and illustrate their loading conditions, also we’ve analyzed common materials used to produce covers and finally common problems and hazards related to these covers are discussed and appropriate solutions, which are taken from different countries experiences, are presented for each.

In this research the effects of waste polymer of PET on the performance of asphaltic mixtures containing rubber asphalt are investigated. To this end, two different sizes of waste PET particles were added into an asphalt concrete at different percentages of 2, 4, 6, 8 and 10% (by the weight of asphalt binder). After determination of the optimum binder content of each mixture, they were subjected to different tests of Marshall Stability, indirect tensile strength and dynamic creep tests. Dynamic creep tests were conducted using UTM-10 under 300kPa and temperature of 40°C for evaluating the permanent deformation behavior of the mixtures containing different percentages of PET. The results showed that the addition of PET into the asphaltic mixtures containing rubber asphalt resulted in the improvement of Marshall Stability and Marshall Quotient compared with the control mixture without PET, with the highest stability was obtained for the mixtures containing 10% of PET. The indirect tensile strength tests results showed that, for both sizes, the highest indirect tensile strength was obtained by the addition of 2% of PET, beyond which the indirect tensile strength decreased with increasing PET content. The dynamic creep test results showed that the mixtures containing PET have a different behavior under dynamic loading compared with that under static loading. It was found that the addition of PET results in the reduction of resistance against permanent deformation under dynamic loading, such that, the resistance decreased with increasing PET content. The Marshall stability, indirect tensile and dynamic creep tests results showed that the mixtures containing finer PET particles have a higher resistance than those containing coarser particles.

Excavation tunnels subway traditional and mechanized two methods of all sections are done.Method selection the tunnel to the tunnel, project scheduling, overburden status, urban location and traffic, geological conditions, ground level subsidence, and other considerations, the efficiency of the method is dependent.This paper introduces a a variety of tunnel excavation methods and the advantages and disadvantages of their perform operations and processes are briefly described.The purpose of this paper is to provide young engineers familiar with the basic concepts are the tunneling industry.

The share of railway transport is inconsiderable in Iran. This could be one of the major causes of the high rate of fatalities in Iran. So the issue of road safety, regardless of different transport modes, is not perfect. Safety can be described as an issue by the three main indexes: exposure, risk, and consequence. With changes in any of these three dimensions, safety requirements will change. One method of reducing exposure index is developing safer transport modes such as railways. In This paper, the relationship between the share of rail and road traffic fatalities through statistical analysis of data from Germany, Denmark, Belgium, and Austria countries is analyzed. In these countries with high rail density, road death rate is decreased with increasing the share of rail.

The design of major transport infrastructure in the Late Pliocene sediments of the Pliocene to the lithological and tectonic features regions, should be accompanied by detailed geological studies.The drift began at the railway crossing, the direction of movement (to force), the rates that were measured through the six-month period instruments, detectors that were specified drift depth, topography harvest limits and stratigraphy drift is used. Data was from the study indicate geology, the speed, direction and drift volume. The implementation of variants in the vicinity of the railway specific bridge due to its high financial burden is not possible and therefore drift energy reduction processes or to create a buffer against it, were studied. Field observations, drift conditions and the location of the data, we were forced to reduce the energy and drift to be used to plan the implementation of retaining wall. So, while providing full details of the proposed scheme in this paper, the reinforced soil walls (reinforced with geogrid) was conducted.

In this paper, the 1st Shahran square that is located in the North West of Tehran metropolis, was simulated and analyzed with Aimsun simulation software based on microscopic level. Field study data were obtained from census of cars and buses passing through each side of the square and around it in peak hour traffic (from 5 pm to 6 pm). In addition, the percentage of the route choice was specified to determine traffic conditions. After collecting and entering data in Aimsun, calibrating values based on observed drivers’ behavior were entered to achieve validation and verification of the input data. For this purpose, two main scenarios were examined. In the first scenario, the current situation of the square with just one U-turn on the east side of the square was evaluated. Then, as a traffic solution in the second scenario, three U-Turns were designed on the west side, north side, and south side of the square. The output results from comparison two scenarios showed a downward trend in travel time and number of stops, while, speed rate and traffic flow rate showed an upward trend.