Research Article
Mohammad Alidousti; Mohammad Reza Farzad Behtash; Alireza Estelaji
Abstract
Statement of Problem: The city of Tehran as a political, social and economic capital has a decisive role in the fate of the country. Tehran with a population of more than 8 million people is the 24th most populous city in the world. 8.10% of the population has a share equal to 21% of the country's gross ...
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Statement of Problem: The city of Tehran as a political, social and economic capital has a decisive role in the fate of the country. Tehran with a population of more than 8 million people is the 24th most populous city in the world. 8.10% of the population has a share equal to 21% of the country's gross domestic product (GDP) and more than 50% of tax revenues as well as 55% of bank deposits are provided from the city and province of Tehran. At the same time, the city still suffers from many problems, the most important of which is the unfavorable situation of builders, to the extent that according to the same study and a survey of construction industry experts in Tehran, 42.5% of them consider the quality of construction in Tehran poor or catastrophic. Dilapidated and dysfunctional structures in the heart of Tehran and with very difficult accesses add to the concern about possible crises. Although several programs have been carried out in the field of repair and renovation of worn-out structures, but so far the city administration has not met expectations and we still face this problem. The purpose of this study is to introduce the effective first steps to create a codified method (planning) for implementation so that the results can guarantee the quality of ongoing construction. The research method was descriptive and correlational and a questionnaire was used for this purpose. The statistical population is the target of professional engineers of Tehran Building Engineering Organization. 120 questionnaires were analyzed by SPSS and SmartPLS software. Based on the findings of this study, the use of six important factors in planning, including: implementation of construction quality assurance insurance, mandatory contractor in construction, accurate and complete implementation of the building technical certificate, adjustment and increase of engineers' fees along with increasing public awareness and change and Amend national building regulations. According to the findings of this study, it can be said that the most important finding of this study is that the process necessary to establish insurance quality assurance of the builder is clearly explained.
Research Note
Alireza Khedri; Mahdi Moharrami
Abstract
Petrochemical projects and energy supply areas in all parts of the country are both strategically and economically very important due to the large volume of dedicated budget. In recent years, due to fluctuations in cooperation between domestic companies and contractors, Consultant and foreign investor ...
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Petrochemical projects and energy supply areas in all parts of the country are both strategically and economically very important due to the large volume of dedicated budget. In recent years, due to fluctuations in cooperation between domestic companies and contractors, Consultant and foreign investor under the influence of sanctions, these projects have been delayed. This study tries to identify the factors affecting it and to provide appropriate executive solutions to decision-makers and eliminate those factors to reduce delays in the project. Help the oil and gas industry infrastructure. Nowadays, in the world, especially in developing countries, the use of contracts to reduce delays in projects and increase performance and value engineering has been considered. However, in our country, despite the use of this method, international restrictions, including sanctions, have caused problems that we address in this study. Using the study of available sources, a list of factors affecting the delays was prepared and using the opinion of experts, these commoners agreed and approved them. Then, by preparing an online pairwise comparison questionnaire, these factors were prioritized and hierarchical analysis was performed using TOPSIS method. The results showed that finding and concluding a contract with a foreign investor has the greatest impact and delays in holding tenders have the least impact on delays in infrastructure projects in the country's oil and gas industry.
Research Article
Morteza Naghipour; Arash Javadi Ashrafi
Abstract
Concrete-filled steel pipes (CFSTs) are increasingly used in the construction industry due to their high bearing capacity, high ductility and energy dissipation capacity, as well as high toughness and toughness under cyclic loads compared to conventional hollow steel pipes. Have become common. In this ...
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Concrete-filled steel pipes (CFSTs) are increasingly used in the construction industry due to their high bearing capacity, high ductility and energy dissipation capacity, as well as high toughness and toughness under cyclic loads compared to conventional hollow steel pipes. Have become common. In this research, numerical evaluation of cyclic behavior of steel columns filled with concrete polygon sections is the main direction of the article. The research method of this study was based on finite components using Abaqus software. For the accuracy of the numerical responses, a numerical sample was simulated in accordance with the laboratory sample and the results were validated. In the next step, parametric study was performed on the cyclic behavior of steel columns filled with polygon sections. The geometrical parameters of column cross section, steel wall thickness, concrete compressive strength and axial force ratio were investigated. The geometrical shape of the cross sections was 4, 6, 8, and 12 rectangular and circular. Steel wall thicknesses of 3, 4 and 5 mm, compressive strength of concrete 20, 30 and 40 MPa and axial force ratio above the column are considered 0.1, 0.3 and 0.5. Loading into concrete filled steel columns with two polygon sections was done in two stages, first in axial pressure load and in the second stage in cyclic load as control-displacement. The results showed that the geometric shape parameter of the column cross section when changing from circle to rectangle causes maximum increment of indices of stiffness, force the yield, ultimate strength, ductility and energy are 37%, 36%, 32%, 64% and 71%, respectively. The ratio of the axial force applied to the structure to the maximum lateral load utilization with respect to the values of 0.3 is recommended and the cross section geometry index has the greatest impact on the strength, ductility and energy dissipation without any change.
Research Article
Saeed Radmanesh; Amirhossein Bazaee; Roozbeh Aghamajidi
Abstract
In general, Spillway are divided into two types linear and non-linear, among which, the Morning Glory overflow is a non-linear overflow. In some cases, the hydraulic performance of the overflow is affected by the immersion coefficient and its hydraulic efficiency is reduced and affected by the immersion. ...
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In general, Spillway are divided into two types linear and non-linear, among which, the Morning Glory overflow is a non-linear overflow. In some cases, the hydraulic performance of the overflow is affected by the immersion coefficient and its hydraulic efficiency is reduced and affected by the immersion. Structures such as vortex breakers (separators of flow lines to increase transit efficiency) and to increase overflow efficiency should be used. In this regard, using dimensional analysis by Buckingham method, it was determined that the overflow coefficient of the overflow is a function of variables such as vortex breaker height ratio (Hvb / Rs), vortex breaker thickness ratio (Tvb / Rs), number of vortex breakers (VB) and overflow shape factor ( Sf) is. The experiments of the present study were performed on a square flume with dimensions of 2.5 × 2.5 and a height of 2 m 0.20 1 1.05 /0 1.05 m3. The results showed that the overflow of stepped Morning Glory (12 steps) and vortex breaker with high height and 6-array arrangement has a much better and more suitable performance compared to non-stepped overflow and has increased the permeability coefficient by 23%.
Review Article
Reza Akbarigheibi; Daryoush Jalili; Vahid Bakhshi
Abstract
Today, with the increase in the volume of traffic and the growth of travel, organizing and managing traffic is one of the necessities of urban medicine. Also, Traffic identification has become a challenging task in recent years. Recently, deep learning methods have been extensively studied for network ...
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Today, with the increase in the volume of traffic and the growth of travel, organizing and managing traffic is one of the necessities of urban medicine. Also, Traffic identification has become a challenging task in recent years. Recently, deep learning methods have been extensively studied for network traffic classification recently. Unfortunately, these models require a large amount of training data. Another challenge with most traffic classification methods is that the features must be extracted by an expert. In these methods, finding the desired features that lead to a better classification is very tedious and time-consuming. Therefore, new measures are needed to reduce urban traffic more than before. The purpose of this study is to investigate new methods of urban traffic control. Which is mostly based on previous research and analysis. Studies on new methods and models of traffic reduction, including technology, technology and intelligent systems, have been collected and reviewed in recent years. The results show that the use of these new technologies can estimate the volume of hidden traffic, improve traffic flow, accurately predict travel time operations and traffic volume, determine the appropriate service level, increase the capacity and efficiency of existing infrastructure. Transportation and specification of travel time, maximum queue length, queue stop, vehicle delay, stop delay and number of stops.
