نشریه عمران و پروژه
سال چهارم شماره 5 (پیاپی 39، امرداد 1401)

This paper presents an exact formula for considering soil stiffness under the foundation. This formula derived from a 3D modeling of eight strip footings with different foundation widths supported on a soil medium. In the case of an earthquake, the behavior of the substructure soil plays an important role in the response of the structure. Studies show that the dynamic response spectrum of a structure on a flexible foundation is different from the response spectrum of a structure on a rigid foundation. Hence it is important to model the soil medium correctly to reach the best seismic results. There are different methods for modeling soil-structure interaction. These models use a constant value for modeling the soil stiffness. However, the soil stiffness varies along the foundation and should be calculated by analytical studies. This paper provides a simple formula which shows a non-uniform soil stiffness under the strip foundation and can be used for practical purposes.

In today's world, urbanization in all its dimensions is expanding rapidly, and city managers are trying to meet the expectations of citizens and organizations, from the city and urban management, and to manage the city in a changing environment. Today, plan and operate. Administration of cities in the past, due to their small size and population, was possible through government assistance such as tolls. Meanwhile, government budgets are normally limited and inefficient to develop the infrastructure needed by a country. This research identified and prioritized the challenge of such contracts using qualitative and quantitative methods, which can be referred to the challenges of construction and operation, the private sector and the challenges of the public sector. The results of this study include the public sector challenge with a weight of 0.421, the private sector challenge with a weight of 0.391 and the manufacturing and exploitation sector challenge with a weight of 0.188, which were placed in the first to third priorities, respectively. In addition, four key and effective factors in the successful implementation of public-private partnership schemes can be mentioned as follows: Ensuring free access to the market and the possibility of fair and non-discriminatory competition in the economic context of society, protection of the interests of society And maximizing the added value of public-private partnership schemes, defining the optimal level of government assistance both to identify necessary and sustainable projects and to prevent the misuse of government property for windfall profits and to evaluate the most effective type of partnership with regard to The type of project desired.

Some of the important benefits of cold asphalt include conservation of natural resources, cost and energy reduction. Meanwhile, warm asphalt mixtures have higher durability and resistance than cold mixtures, but the use of hot asphalt mixtures causes environmental pollution, the release of toxic and harmful gases, and also reduces the safety of workers. Therefore, today, the use of cold asphalt mixtures is increasing in order to protect the environment and also work risks, which is used with this type of asphalt along with emulsion bitumen. However, the use of cold asphalt produced in factories with emulsion bitumen leads to problems such as rutting, thermal cracks, reduction in strength, etc. Therefore, the need to use additives in order to improve the functional characteristics of this type of asphalt is felt. Considering the importance of the subject, in this research, a review of the studies conducted in the field of the effect of different additives on the functional characteristics of recycled cold asphalt produced with emulsion bitumen has been done. Finally, according to the results of the studies, it can be said that asphalt mixtures produced with emulsion bitumen have very low resistance to environmental factors and humidity, and therefore the use of additives is recommended. The results showed that the use of different additives improves the resistance of the asphalt mixture against moisture, which is more evident in the samples modified by combining polymer with cement and polymer with lime than other additives. shows. Also, due to creating a three-dimensional network in the bitumen and actually reinforcing the bitumen, polymer materials can increase the asphalt resistance and Marshall endurance.

To eliminate the defects of merely systematic materialistic attitudes, one can refer to the divine systematic thinking and benefit from the transcendental teachings of Islam. Non-linear thinking and dynamic view of phenomena and consequences is the neglected point of managers' decisions in businesses and commercial and non-commercial organizations. The employees of the organization always seek to know the results of their performance and are interested in monitoring their performance changes. In all the organizations of the world, managers and organizational leaders seek to improve and improve the performance of their organizations. Organizational performance is an indicator that measures how an organization or institution achieves its goals. With the aim of investigating and evaluating organizational performance through systemic thinking, this article reviews the viewpoints of managerial and organizational performance evaluation criteria, indicators and types of performance evaluation models. The results showed that the design and selection of performance evaluation indicators is one of the basic phases in the design of the organizational performance management system. In the performance evaluation process, the organization excellence model (EFQM) is a self-evaluation process and a comprehensive systematic method to identify the organization's strengths and improvement points. As a result, the organization compares itself with the best in the world or national class.

One of the effective methods in improving the seismic behavior of structures is the use of light steel structures (LSF) systems. The (LSF) system, which is made of cold-rolled steel sections (CFS), has been widely used in the industrial production of commercial and residential buildings for about 20 years, and as a suitable alternative to traditional construction methods. It has found a special place in the construction industry of advanced countries. These types of systems receive a small amount of lateral force during severe earthquakes, and due to two special properties, i.e. prefabricated structural members and suitable thermal insulation, these systems are widely used in The advanced countries of the world are used to build residential houses. Wooden buildings show good resistance against earthquakes. In a wooden structure, low to moderate vulnerability to earthquakes is usually observed. One of the reasons for the good performance of these buildings against earthquakes is their light weight compared to other types. Also, the presence of many non-structural components such as load-bearing walls increases the amount of energy wasted by the building against earthquakes. In addition, the presence of many joints increases the malleability of the building.