نشریه عمران و پروژه
سال ششم شماره 2 (پیاپی 50، اردیبهشت 1403)

Over the past four thousand years, the history of transportation began with pack animals and sailing boats and evolved with the invention of the wheel and steam engine. Air transport, with the ability to quickly cover long distances, has its own advantages and challenges. The volume of air freight transportation in Iran is relatively low compared to overall transportation, and there is a need to reduce costs and increase innovation. Air transport plays a crucial role in transporting valuable or time-sensitive goods in global trade. The status of air freight transportation in Iran has been examined in three main sections. First, the trend of transported volume, both domestically and internationally, has been recounted over the past decade, and consequently, information regarding the performance and market share of airlines in this sector has been discussed. Additionally, the role of airports (cities) in air freight transportation has been scrutinized, and data related to the volume of incoming and outgoing cargo from airports have been highlighted. Finally, a comparison between domestic and international air freight transportation has been conducted, providing an analysis of the performance of airlines in these two domains. To develop air freight transportation in Iran and enhance the efficiency of this industry, suggested solutions include attracting domestic and foreign investors, developing open skies agreements with other countries, leveraging Iran's unique geographical position to establish north-south and east-west corridors in the region, and reducing cargo transportation costs by outsourcing the airport transportation sector to airline companies.

The purpose of this research is to analyze the role of integrated components of sustainability in the construction industry in the construction projects of Imam Khomeini Port. For this purpose, a main hypothesis and three sub-hypotheses were developed. From the point of view of the purpose of this research, it is a development-oriented applied research, and from the point of view of methodology, it is descriptive-analytical (quantitative). The statistical population of this research includes specialists and construction experts of the Imam Khomeini Port Engineering System Organization, and the sample size was selected according to Kersey and Morgan's table by simple random sampling method of 120 people. The method of collecting information is library and field methods. Data analysis was done in two parts, descriptive statistics and inferential statistics using Pearson correlation coefficient, regression analysis and Friedman test by spss software. The findings indicate the confirmation of research hypotheses at a significance level of less than 0.05. Based on this, indicators of economic sustainability, social sustainability and environmental sustainability affect the success of construction projects.

The global increase in construction activity has resulted in a significant rise in construction-related accidents. Tunnel construction projects are particularly complex, which increases the risks involved. Numerous studies have been conducted on the subject to reduce the risks and improve safety. These studies have explored safety standards and regulations, methods of safety assessment, and environmental factors that can affect safety. Proper identification and management of these risks are crucial to ensure the safety of labourers and the successful completion of the project. The purpose of this study is to provide a comprehensive review of the risk factors that can affect construction safety in tunnels. A better understanding of tunnel safety can be achieved through the identification and analysis of risk factors, leading to improved workplace safety management strategies in the tunnelling industry.

Concrete Damaging and reduction of durability characteristics under sulfate attack is one of the important matters. Compared to the situation where concrete is always immersed in sulfate environments, the damages caused in dry and wet conditions are more complex. The dry and wet cycle is a significant factor that affects on the sulfate attack of concrete. Some concrete structures such as piers, are subject to wet and dry cycles due to sea tides, which causes a continuous process of destructive ions entering to the concrete matrix during wetting, and increasing cracks during the drying process. Considering the wide using of high-strength concrete and the weaknesses of this concrete in the mentioned conditions, the present study has investigated the compressive strength, tensile strength, separation and shrinkage test of HS, FRHSC concrete reinforced with polypropylene (PP), steel (ST) and hybrid fibers under the conditions of dry and wet cycles in the environment containing magnesium sulfate for 6 months. The results of this study show that although dry and wet cycles reduce the strength of concrete containing steel fibers, the effect of these fibers in increasing the compressive and tensile strength of HS concrete is much greater compared to PP fibers. The use of steel fibers, polypropylene and a combination of steel fibers and polypropylene has reduced the shrinkage of high-strength concrete samples by 13, 24 and 33%, respectively (compared to HS concrete without fibers).