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Showing 6 results for Tehran City

Farimah Bakhshizadeh , Hani Rezayan, Mehry Akbary,
Volume 2, Issue 1 (4-2015)
Abstract

Air pollution has become one of the main problems of cities. Among the sources of air pollution, vehicular traffic plays an important role. Planning for efficient management and control of the air pollution caused by vehicular traffic requires accurate information on spatio-temporal dispersion of the pollutions. This research studies 3D spatio-temporal dispersion of NOx pollution caused by vehicular traffic at Valieasr-Fatemi intersection resides in Tehran, Iran. It is selected for being crowded and having the required meteorological and pollution data sensed by the Air Quality Control Corp. of Tehran Municipality.

This study uses GRAL that is a local micro-scale air dispersion model defined based on Euleran-Lagrangian dispersion models. It investigates the level of spatio-temporal autocorrelation generated by GRAL simulations at both 2D and 3D modes and discusses how it adapts with the reality.

Adopting the GRAL air pollution dispersion model, streets are defined as the linear source of pollution of NOx caused by vehicular traffic. The traffic rate is estimated based on street areas and directions, the designed average traffic velocity, traffic volume and car passage counting at the intersection. The 3D geometry of the buildings is also added to the model. All the required data that were available for winter of 2007 are gathered and introduced into the model.

The model is executed at 9 heights vary from 1.7 m to 52.5 m. These heights are defined covering a range from an average human level height to average building height and above. These levels are considered both separately in 2D mode and integrated into a 3D mode. The formation of NOx clusters is investigated analyzing their autocorrelation using Moran Index at global and local scale.

The calculated Moran-I at global scale at each 9 levels of heights, varies from 0.7 to 0.9 that depicts the validity of the GRAL model adopted to simulate the expected autocorrelation of pollution density affected by spatial issues. The Moran-I increases at higher levels as less air turbulence happens. However the result show that the turbulence increases temporarily at about 10m to 15m which are the average building heights. At local scale, the Moran-I/Anselin shows that HH clusters dominate at lower levels, around streets central areas that are farther from the buildings, and around the intersections. At higher levels, esp. higher than buildings average height, the LL clusters dominate. However the HH clusters formed around intersections, while are shrank, are still visible at high levels. The turbulence caused by building fronts and their down wash effect is also shown in the result as no definite cluster is formed near the buildings front and back.

The autocorrelation analysis is also carried for an integrated 3D model consists of all the 9 levels of heights. Considering the weight matrix for a 20m 2D neighborhood and 1m/s dispersion of the pollution vertically, the global calculated Moran-I equals 0.229 which shows existence of a spatio-temporal autocorrelation of the results generated by GRAL. At local scale the results show that the HH clusters have higher temporal dispersion rate than LL clusters.


Hassan Afrakhteh,
Volume 2, Issue 4 (1-2016)
Abstract

The City-region of Tehran is encountered with various environmental problems, including traffic, air pollution, lack of drinking water and green space, physical texture conflict, flood and earthquake. Capital accumulation has considerable role in shaping spaces which can create and intensify environmental disaster in special socio-economic situation. The second cycle is the conversion of capital to fixed and long-term assets with the aim of further benefits, which in fact produces two types of artificially environment during this process namely the built environment for production, and the built environment for consumption.

The third cycle is aiming to connect science to production and increase production capacity by investment in science and technology. When production of surplus value reduced in the first cycle, surplus value of second cycle increases through speculation and real estate transaction (real estate capital). Therefore, the owners of the lands and buildings are encouraged in production, trade and supply of these type assets.

In the courtiers that are legally and administratively encounter with tax receipt problems,  urban lands ownership is deposited to market system without any control, hosing transaction continues without any limitation, situation is moving forward to personal vested interests, asset value rises rather than production value, the price of land and construction increase severely. In the above mentioned condition, beneficiaries attempt convert the natural resources including park, mountain, river privacy and road privacy to marketable commodity and legally or quasi legally seize them. Therefore, unreasonable construction and population density increases and city-region will encounter with environmental disasters.  

The main objective of this research is to understand the underlying factors of capital accumulation through construction and its impacts on createion and intensification of environmental disasters in the Tehran city-region.

  Five different regions of Tehran were selected for data collection. "Q-methodology" was used for gathering and analyzing data. The society of communication or people whom the study sought to identify their mentality towards the research topic, were 25 experts selected through purposive sampling. To set the concourse of communication, a combination of primary (experts commented in an interview) and secondary (sources of credit) sources have been used and   34 statements have been developed. After sorting the data for analysis, SPSS software data matrix is ​​formed. Factor analysis, as main method of analyzing Q data matrix has been used based on Q logical methodology.

The results of Q analysis depicted four viewpoints with variance of 95.911 percent on the underlying cause of capital accumulation through construction and its contribution on increasing risk of natural hazards in Tehran city-region.

The first viewpoint has devoted 52.800 percent of total variances and can be titled as" Function of real estate transaction and Non-productive economic domination".

The second viewpoint which has received 18.914 percent of total variances is accordance with "commodification of land and housing". The third viewpoint is" management and monitoring of the city-region space" with 15.163 percent of total variances.  The fourth viewpoints under the title of" monitoring and control of natural resources" has assigned 9.034 percent of total variances.

As result of these processes, land and housing business have weakened society's productive capacity by extensive land use change in the urban peripheral area's due to its huge and quick profit. The above process accompany with selling excess density policy created a powerful political and economic stratum which harmed city sustainable development. The mountainous area of north, north east and west of Tehran, have annexed to metropolis as a result of above mentioned regulation and  may gardens have converted to construction by different gropes and institutions.

Q method analysis depicted that the Tehran City-Region has converted from use value to exchange value. It means that values of the city including work, security, education, leisure and welfare have been lost in favor of exchange value. In other words, the city has been converted to a commodity for exchange and selling in pursuit of profit, rising cost of urban land, building and housing. Consequently, the city-region construction site is extended to the river beds, steep slops and surrounding natural environment. This in turn is leading to rapid land use change and violation of environmental and spatial rules and regulations and intensification of environmental hazards.


Jamileh Tavakolinia, Alireza Mehrabi, Ehsan Allahyari,
Volume 6, Issue 2 (9-2019)
Abstract

Today, air strike on installations and urban areas, is normal. As such, vulnerability assessment cities and provide the right solution for harm reduction is essential. The purpose of this investigation was to identify factors causing damage in the district of twenty in Tehran. The research method is descriptive-analytic and Data collection is library and field. Data analysis is based on using Ahp and GIS. Results show, In the district twenty , There are three zones vulnerable. Including, The old Central, The high-density Dolatabad and sizdah aban neighborhood. These zones are 34 percent of the land. The reason of it is Poor physical structure. Statistical Society is Twenty district in Tehran. Sample size is 384 people of residents of the district. Because, in this area there are strategic factors, is An important part of the tehran city. in the end, are provided The right solution of Reducing vulnerability.


Alireza Kazemi, Behnod Barmayehvar,
Volume 7, Issue 4 (2-2021)
Abstract

Due to the insecurity of the construction industry, the purpose of this study is to evaluate safety management and investigate its impact on reducing accidents of sites in urban construction projects in the south of Tehran. Due to the nature and type of research, the present study is descriptive-correlational and practical research. The statistical population in this study is supervising engineers working in the field of urban construction in the south of Tehran (15, 16, 17, 18, 19, and 20 areas). Therefore, according to the latest statistical report published by the Tehran Engineering System Organization (5000 people) and based on the Morgan table, 351 acceptable answer sheets were collected.
In this research, data collection and information were performed using the library-documentary method and field method (with the help of observation tools, interviews, and especially questionnaires) and through a combined method (quantitative-qualitative) with quantitative nature and focus as well as survey strategy. Also in this research, in addition to utilizing the capacities of qualitative content analysis, the methods of quantitative analysis include descriptive statistics including frequency, average, and standard deviation, as well as inferential statistics including Kolmogorov-Smirnov, Friedman, Pearson, T-tests and regression analysis by SPSS 24 software, was used. Questionnaire questions were validated by reviewing previous research, consulting with experts, and validating with factor analysis and reliability using Cronbach's alpha method.
The results show that among the three effective factors in improving safety management and reducing site accidents in urban construction projects in the south of Tehran, the factors of “use of protective equipment”, “compilation of responsibilities” and “risk management” with averages of 4.0864, 4.0741, and 3.9812 are ranked the first, second, and the third rank, respectively. Besides, the average part of various site accidents is 4.0000.
According to the results of the research, from the total types of site accidents of “injuries to people due to non-use of personal protective equipment”, “damage to urban underground facilities during nailing operation”, “life and financial losses due to standard and unsafe construction site equipment”, “occurrence of silent death in workers' rooms due to unsafe gas appliances and lack of proper ventilation, “collapse of structural parts during welding”, “fall of workers, materials, and equipment from a height”, and “collapse of the walls of the pit and adjacent plaques due to lack of standard and standard excavation” are ranked first to seventh with an average of 5.7692, 4.8148, 3.8490, 3.7322, 3.7236, 3.1282, and 2.9829, respectively.
According to previous research, the “policy (compilation of responsibilities)” factor has the first impact on the safety of the construction industry, but in a case where the field of research is limited to construction projects and urban constructions (personalization) in which in such projects safety management is not generally systematic in the site, the prioritization between the factors affecting the safety management of the site has changed and the “policy (compilation of responsibilities)” factor is transferred to the second rank and the “use of protective equipment” factor is placed in the first rank. Therefore, builders and employers, and that project supervisors must be required to closely monitor this carefully formulate safety responsibilities in construction workshops.
Considering that, the factor of “non-use of personal protective equipment” is in the first place as the cause of site accidents and has already been ranked in the fifth place of safety hazards, so it can be concluded that since the last decade, the factor of “non-use of personal protective equipment” has risen from the fifth to the first rank. Therefore, it is necessary to pay more attention to the use of protective equipment in construction sites in Tehran, project supervisors should be stricter in this regard, and engineering organizations and municipalities should enact stricter rules and regulations.
According to the supervising engineers active in the field of research, “damage to urban underground facilities during nailing method” is in the second place in the classification of common types of site accidents in the field of urban construction of Tehran and nailing method for stabilization of deep urban ditches causes legal problems to enter the privacy of adjacent license plaques and obtain notarized consent from the owners of adjacent license plaques, in addition to the risk of damaging underground urban facilities and causing heavy damage to the project and it is necessary to use other modern methods of deep pit stabilization, including the “Top-Down” method.
In this study, “human and financial losses due to non-standard construction site equipment” is classified in the third rank of site accidents. Therefore, the municipalities and organizations of the engineering system must make the issuance of technical inspection certificates for site equipment mandatory and if the employer and the constructor do not provide the necessary documents in this regard or to prevent the continuation of executive operations.
Because accidents due to non-observance of safety issues in construction sites continue to occur for various reasons, it is necessary to establish stricter rules and regulations regarding non-compliance with safety issues in construction sites in the field of urban construction and the use of a safety officer in the site with relevant educational and professional backgrounds and qualifications is mandatory for all construction sites.
The results of this study show that increasing attention and accuracy in the areas of responsibility compilation, risk management, and use of protective equipment improves safety management and reduces accidents in construction sites in the field of urban construction of south of Tehran.

Ms Paniz Ashrafi, Dr Behnod Barmayehvar, Dr Ehsan-Allah Eshtehardian,
Volume 9, Issue 2 (9-2022)
Abstract

Considering the increase in housing construction in developing societies such as Iran, it is necessary to address the issue of reducing construction accidents, especially in metropolises, and related safety measures with the help of emerging technologies. Therefore, the main goal of the current research is to investigate the use of Internet of Things to monitor and control high-risk points in order to reduce accidents and improve safety in the spaces of construction site in Tehran.
In this applied research, first, a library study was conducted regarding the concept and application of Internet of Things in the safety field of the construction industry. Then, high risk points and activities were identified. After that, in the field study phase, this list was corrected and completed by 52 competent building safety consultants. After that, ten semi-structured interviews were conducted with safety experts and knowledgebale in the field of IoT. Therefore, effective solutions based on Internet of Things were extracted to control and monitor high risk points. Also, in this regard, the current situation and required platforms were explained from the aspects of technology, organization, cost and outsourcing.
In fact, the main findings of this research, in the form of a conceptual model, show that paying attention to the stages of choosing the incident, choosing the desired point and activity, determining the appropriate solution for the determined situation (monitoring the amount of movement and health of the structure, monitoring the proximity of flammable materials with other materials, monitoring the proximity of people and machines and preventing the continuation of movement and determining the limits around the openings) and checking the required platforms (infrastructure, support, accreditation, culture, budget, employers and law), respectively, in order to design and implement IoT-based safety systems in the spaces of construction sites is vital.

 
Masoomeh Hashemi, Ezatallah Ghanavati, Ali Ahmadabadi, Oveis Torabi, Abdollah Mozafari,
Volume 10, Issue 2 (9-2023)
Abstract

Introduction
Earthquakes as one of the most important natural disasters on earth, have always caused irreparable damage to human settlements in a short period of time. Severe earthquakes have led to the idea of developing an infrastructure plan to reduce the risks and damages caused by it. The urban water supply system is the most important critical infrastructure that is usually damaged by natural disasters, particularly earthquakes and floods; hence, the function of the pipelines of the water system determines the degree of resilience and design of the infrastructure against multiple natural and man-made hazards. Considering the inability to prevent earthquakes and the inability of experts to accurately predict the time it is necessary to know the status of earthquake-structure and seismicity in Tehran to determine the amount of earthquake risk in order to make the necessary planning for structural reinforcement. Theoretical and field studies of tectonic seismicity in the Tehran area show that this city is located on an earthquake-prone area around the active and important faults of Masha, north of Tehran, Rey and Kahrizak. The occurrence of 20 relatively severe earthquakes illustrates this claim. Regarding the location of faults in Tehran city, it is necessary to assess the vulnerability of Tehran water facilities.
Research Methodology
The present study is a practical-analytic one. Considering the severity of earthquake damages, it is necessary to conduct earthquake hazard zonation studies in different urban areas and to determine important indicators of damage assessment such as maximum ground acceleration, maximum ground speed, maximum ground displacement. Three indices were considered for mapping earthquake seismic zones and their integration into the GIS presented a seismic hazard map. In the analysis of earthquake risk, it is necessary to evaluate two indicators of risk and vulnerability. To prepare the general hazard power mapping the weights obtained from the ANP model were applied to the existing raster layers via the Raster Calculator command. In this way, the standardized layers are multiplied separately by their respective weights and finally overlapped. In order to evaluate the vulnerability, a series of evaluation indices are introduced and ANP techniques are used. The relative value of each index is then calculated using the multivariate approach using the SAW technique. In order to calculate the earthquake risk based on R = H * V relation, the values ​​of these two components were multiplied. This calculation was performed in GIS software on the risk and vulnerability raster layer and the final result of this calculation was displayed on the map.
Description and interpretation of results
In this study, we tried to estimate the relative risk and risk of seismic hazard on the water supply lines in Tehran, using available data and scientific methods, and map the risk level. These lines should be prepared first by the amount of earthquake hazard risk and then by the risk map, to estimate the earthquake risk on the water supply network. first the earthquake risk then the status of the hazard lines should be calculated. The vulnerability of the water supply lines was calculated using the ANP model by multiplying the total potential hazard risk then substrate transfer network vulnerability risk map obtained transmission network. The highest risk was in the west and north of Tehran. The maps showed the risk potential and the vulnerability of the lines. These areas had high seismic potential and the density of the lines was higher in these areas. Water transmission facilities are at risk and earthquake hazards may be affected by damage to the transmission lines, drinking water to a large population will be difficult, as well as performing necessary zoning to prevent future expansion of the facility in place. These analyzes are a prelude to applying corrective techniques to pipelines to reduce their vulnerability and prevent newly created pipelines from locating in vulnerable areas. Since the results of this study are risk maps along the route of the water supply lines, so in order to prepare a risk control program, we can identify the high risk pipeline map and identify the pipeline vulnerability. And, depending on its location, provided an appropriate prevention and control plan for the conditions surrounding the pipeline environment.


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