FERDOWSI CIVIL ENGINEERING
Year:2021 | Volume:34 | Issue:3|Papers Count:6

At present, the Equivalent Passenger Car Unit (PCU) values, proposed by other international guides, are used in the design and analysis of signalized intersections in Iran. It is likely that this would produce a negative impact of the accuracy of capacity analysis used for these intersections as the geometric design, behavioral attributes and vehicle characteristics are different here. Hence, it was decided to estimate the PCU values for buses, minibuses and motorcycles at Iranian signalized intersections using a multiple linear regression in this study. The required field data was collected from 9 intersections located at Isfahan and Yazd cities and the regression analysis was then performed on the data using SPSS software. Thereby, the PCU values for the motorcycles, minibuses and buses were obtained as 0.46, 1.45 and 2.53. Finally, an overall average PCU value of 2.13 was obtained for the heavy vehicles. The results could be used as the best estimate of PCU values for the similar Iranian signalized intersections.

Environmental protection is one of the most important factors of sustainable development, so that the political and economic growth of countries, regardless of it, is worthless. Considering the role and position of separating walls in construction, the present study, has investigated the environmental effects of common separating wall systems in Iran. For this purpose, seven environmental parameters including: Energy Consumption in Construction Process, Consumption of Important Resources and Raw Materials, Water Consumption in Construction Process, CO2 Production Due to Energy Consumption in the process of construction, the amount of thermal resistance of the walls, the amount of waste produced by the implementation of the walls and the beauty of the walls are considered as evaluation criteria. Regarding these criteria and using the TOPSIS method, this study evaluates the five most common separating wall systems in Iran and determine the most compatible eco-friendly system. Five different types of walls, including solid clay (SC) bricks, hollow clay (HC) blocks, autoclaved aerated concrete (AAC) blocks, three-dimensional (3D) sandwich panels and gypsum boards were investigated in this regard. The results show that according to experts, among the mentioned criteria, the criterion of "water consumption" with a relative value of 0.195 is the best and the criterion of "beauty" with a relative value of 0.049 is the least important. Thus, the results of this study, on the basis of all criteria, showed that the gypsum board has the most and the 3D sandwich panels has the least environmental compatibility.

One of the possible consequences of earthquakes in saturated areas is soil liquefaction and as a result the failure of foundations of buildings, types of infrastructure, bridges and many other disasters. In this study, in order to evaluate the potential of soil liquefaction on 79 samples from China Tangshan Earthquake Database, several intelligent classification models were constructed with the help of Orange software. Therefore, the performance of 5 intelligent classification methods (Logistic Regression, Artificial Neural Network (ANN), Support Vector Machine (SVM), K-fold Nearest Neighbor (KNN) and Random Forest) were compared based on different criteria. The results showed that SVM, ANN and Logistic Regression methods have a high ability to predict soil liquefaction class and among them the Logistic Regression method with AUC index (0.98) was selected as the best method. In addition, the study of the effectiveness of variables using three criteria of Information Gain, Information Gain Ratio and Gini Index, indicates that the variable measured CPT tip resistance is the most effective variable and is the first priority. The variables of cyclic stress ratio and peak acceleration at the ground surfaceare also important features.

In this work, the effect of MgO on the treatment of a natural and contaminated clay soil with phenanthrene was studied through conducting various experimental tests including Atterberg limits, standard compaction, uniaxial compressive strength (UCS), and SEM tests. The contaminated soil was prepared artificially in the lab. Natural and contaminated soil were mixed with 5, 10, 20, and 30% of MgO as an agent. The results showed that phenanthrene changes the structure of the soil and causes a reduction in Atterberg limits, wopt, UCS, and E50 of the soil. The results also indicated that the UCS and E50 of mixture natural and contaminated soil with different percentages of MgO are increased and the amount of increasing of them is dependent on the percentage of MgO and curing time. SEM results also showed that the formation of carbonation products due to hydration of MgO is effective in increasing the strength of treated soil samples.

Despite the growing trend of car use in cities, a significant part of the users of city roads is drivers. Level-crossing intersections are a common passageway for pedestrians and vehicles, and due to the large volume of traffic in these areas, the slightest irregularity in the flow of traffic causes a severe reduction in the capacity of the intersection. Violation of red lights by drivers is one of the problematic factors in traffic light intersections and the occurrence of traffic accidents for pedestrians. The present study aimed to identify the factors affecting this phenomenon, by combining a set of data observed from 101 vehicles, demographic variables such as age, gender, coverage, and weight of drivers were examined as possible parameters affecting red light violation. The results were evaluated by statistical tests to determine the significance of the effect of each variable. Examination of each of the behavioral indicators showed that red light violations were consistently related to age, gender, and clothing, and weight.

Increasing traffic congestion in urban thoroughfares will have detrimental negative effects such as increasing air pollution, increasing fuel consumption and increasing road user dissatisfaction. General strategies for controlling traffic congestion can be divided into three parts, which are: creating a restricted traffic area, turning traffic plan, and traffic congestion pricing. In the present study, the mentioned strategies were prioritized using the combined Delphi method and Analytic Network Process (ANP). The metropolis of Mashhad was also selected as a case study in this study. Based on the results, the traffic congestion pricing strategy with a score of 0.484 was recognized as the best traffic congestion control strategy in metropolitan areas. The strategies of the turning traffic plan and the creation of a restricted traffic area also gained the second and third priorities, respectively, with a slight difference. The indicators of the travel cost, using of public transportation and single-occupancy car traffic were also recognized as the most important indicators affecting the evaluation and prioritization of traffic congestion control strategies, respectively.