امید بامشاد

Several studies have been conducted in the field of construction and project management to define criteria for assessing the success of construction projects. One of the most important applications of these studies is evaluating the performance of construction projects. These criteria are vital, due to the constraints on resources and the vital need for construction worldwide. Considering the importance of the subject, especially in terms of evaluating the success of the project, this paper reviewed and evaluated the most prominent studies and novel approaches, including 45 papers with an average of 528 citations. In total, four approaches were identified, introduced, and evaluated. The achievements of this study can provide a good perspective for a better understanding of the concept of success for construction industry professionals, including leaders and project managers of construction projects, and pave the way for researchers and scholars in the realm of construction industry and project management.

With the increasing population and decreasing of earth's resources and the pollution of water, soil and air in the last few decades, environmental problems have become more visible than before. One of these problems is the excessive use of resources and excessive production of waste. Therefore, important measures have been taken in this field in recent decades, which are mostly offered in engineering and waste management. One of the important management strategies that have been implemented in this field is source reduction (reduction of produced waste in order to preserve resources and reduce waste) as the main goal and in the next stages recycling waste into the life cycle and preventing its burial through Material-energy recycling. WARM model (waste reduction model) is a tool for managers in this field, which is a road map for managers who make decisions for the future of waste management of a city or a country. This model is able to compare different management scenarios with the current situation. In this study, a proposed plan for the waste management of Tehran province for a 20-year perspective is presented in order to reduce the landfill by 30%. All input items are the default WARM model, and according to the available information and schematically, after examining several scenarios with regard to the composition of Tehran's waste and comparing them, a decision has been made about the optimal scenario.

One of the solutions for architecture sustainable development is industrial implementation of buildings systems with sustainable architecture principles. Industrialization is increasing the use of human resources, raw materials and capital in order to respond to the housing needs of the society and economic productivity by using new and sustainable technologies that are organized and coherent in a regular and modular structure. Today, with the development in the construction industry and the ever-increasing need to buildings, we need solutions with the goal of sustainable architecture planning, management and coordinated growth of related industries. In this research, the introduction of Tronco system, its construction method and technical specifications including structural elements, architectural features, safety and its strengths and weaknesses have been discussed. With regard to sustainable urban development, it can be concluded that the Tronco system has the ability to become a sustainable system. Also, this system has a favorable level of energy consumption optimization and brings sustainable development in architecture.

Leadership inefficiency was detected as one of the most important factors for project failure. On the other hand, despite the development of various theoretical concepts and theories in the field of leadership, many questions remain unresolved in this category. This has attracted the attention of many researchers and scholars in recent decades. In this way, a review of studies conducted in the field of leadership shows that all studies in this field, can be divided into six clusters. It can be seen that a total of two types of research are exists: the first type is understanding the term leadership, the nature of leadership and its relationship with followers, competencies, models and theories of leadership. The second type has also analyzed the effect of leadership role in the pillars of the project. Analysis of these studies provides a first step towards receiving new ideas and important research gaps in the field of leadership studies in construction projects. In this article, after library studies in the field of construction industry (challenges and problems), project leadership and management and general studies in the field of construction project leadership, two new approaches are identified and introduced. These approaches, which include the "horizontal leadership and balanced leadership" and "effective leadership", are analyzed in this article. The studies conducted in this article can provide new ideas for research to those researchers who beside quantitative research, are interested in qualitative research in the field of human resource management in construction projects.

In addition to higher carrying capacity, ballastless railways require lower maintenance costs than ballasted ones. Nevertheless, the rail seat abrasion (RSA) is one of the most important factors of damage to the slab railways. In this study, the effect of RSA on the performance of prestressed concrete slabs has been investigated using finite element method. For this purpose, the loss of prestressing force without considering abrasion, abrasion of 5.12, 25 and 37.5 mm with different values of loss of prestressing force, abrasion of 5.37 mm with different values of compressive strength and different values of abrasion along with the removal of prestressing force in the longitudinal direction in the structure has been checked. The results showed that due to the linear behavior of concrete under the range of loading and the absence of cracks in the structure, changes in prestressing force, removal of prestressing force in the longitudinal direction have minor effect on the mid-span displacement (<2%). However, with increasing the prestressing force drop from 10% to 20%, the displacement is reduced by 50%. In general, it can be found that increased abrasion reduces the capacity of railway. The effect of increasing the abrasion on the maximum mid-span displacement in prestressed concrete slab line is not linear and the higher the amount of abrasion, the greater the amount of displacement increases.

The steel plate shear wall (SPSW) as a lateral bearing system in high-rise buildings has been focused in recent decades. Today, these lateral bearing members with high ductility, high energy absorption, and high initial stiffness are used in new buildings as well as rehabilitation of existing buildings, especially in earthquake-prone countries. The use of stiffeners in the SPSW reduces the thickness of the infill plate, and increases the strength and stiffness of the SPSW. The aim of this study is to present a new arrangement for stiffeners with high performance in order to achieve higher shear strength and lateral stiffness. For this purpose, after validating the numerical modeling, several SPSWs with common (horizontal-vertical and diagonal arrangement) and proposed arrangement (diagonally along with horizontal-vertical) of stiffeners were modeled in Abaqus finite element software and were subjected under monotonic and cyclic loads. The results showed that the suggested arrangement provided more confinement for the infill plate and enhanced the final shear strength of the SPSW by 47.5%.

The use of concrete in construction projects is increasing day by day. Making concrete with different properties, compatible with the conditions of each project, is necessary and unavoidable. So far, researchers have conducted research on the characteristics of this type of concrete. However, the role of water consumption in the mixing and curing of this type of concrete has not been studied much. Also, in some countries, studies are being conducted on the use of magnetic water and its effect on concrete. The purpose of this article is to investigate the changes in the properties of self-compacting mortars in the fresh state, due to the use of magnetic water in the construction phase, and therefore small slump tests and small v-shaped funnels are used as important criteria using normal and processed waters. It has been done for 5, 10, 15 and 20 minutes. The results of the tests show that magnetic water improves the rheological properties of fresh mortar.

Under acid rain conditions, physical and chemical reactions occur in the concrete structure, which leads to a change in pH. As these reactions continue, the concrete begins to lose its mechanical strength, leading to cracking, weight loss, and eventual structural damage. Since the control of acid rain and its effects on the environment is inevitable in some cases, researchers have done many studies on this topic and have proposed solutions to eliminate or control its effects. One of the new solutions in this field is the use of nanoparticles. In recent years, studies have focused on silica nanoparticles, with the aim of using this material to further enhance the properties of concrete. The addition of nanosilica to concrete reduces the water permeability of the concrete as well as higher resistance to chemical attacks. In this paper, the mechanical properties and durability of nanosilica-containing concrete including weight loss, compressive strength, electrical resistance and water absorption under acidic conditions are investigated. By increasing nanosilica to concrete under normal conditions, the mechanical properties of concrete are improved, but according to the observed results, when the samples are placed in acidic conditions, the nanosilica in the samples reacts with acid and the performance of nanosilica improves the properties. The mechanical properties of the concrete deteriorate due to the mechanical replacement of the percentage of cement with nanosilica.

Self-compacting concrete is one of the most important and significant achievements of concrete technology. In some countries, studies are being conducted on the use of magnetic water and its effect on concrete. According to the results of this research, by applying a magnetic field to ordinary water, the structure of its molecules changes so that it can be said that as water molecules pass through a magnetic field, there is a significant change in the arrangement of them in the liquid. In this paper, changes in the properties of hardened self-compacting mortars due to the use of magnetic water in the fabrication and processing stage have been investigated. It has been done for 5, 10, 15 and 20 minutes using ordinary water as well as processed water. The results of the experiments show that magnetic water improves the strength standards of hardened concrete. Therefore, in order to achieve a certain level of efficiency and strength, if the magnetic water is used, the ratio of water to concrete or superplasticizer can be reduced.

Nowadays, Steel Plate Shear Wall (SPSW) is considered as a suitable alternative to conventional lateral load resisting systems that used for earthquake resistant design of structures, because of high post buckling strength, significant ductility, stable hysteresis characteristics and high initial stiffness. Also, steel plate shear wall has lighter weight of structures, increased floor area, quicker speed of construction, significant economically affordable and high quality control compared to a traditional reinforced concrete shear walls. Study on behavior of steel plate shear wall was began in 1970s with the aim of providing an easy method for the analysis and design. The initial experimental and analytical researches clarified varies aspects of seismic behavior of steel plate shear wall, but it is still unknown, because of its complex behavior and design. Although some researches on steel plate shear wall has been done since the early 1980s, the appropriate performance of structures that had steel plate shear wall as lateral load resisting systems in the Northridge, USA (1994) and Kobe, Japan (1995) earthquakes caused researchers and working engineers to investigate and implement the steel plate shear wall system to a greater extent. Analytical and experimental research works and studies, provided primarily in Canadian, US and UK universities on steel plate shear wall considered different facets of the seismic behavior of steel plate shear wall and flourished the essential procedures for its application as an effective lateral load resisting system. However, in order to investigate the performance of steel plate shear wall comprehensively, wide range of nonlinear behavior has to be assessed and predicted and it requires hysteresis models that are capable to consider all deterioration modes. One of the comprehensive analytical hysteresis models is the modified Ibarra-Krawinkler (IK) deterioration model that provides four deterioration models including basic strength deterioration, post-cap strength deterioration, unloading stiffness deterioration and accelerated reloading stiffness deterioration for systems with bilinear, peak oriented and pinching behavior. In this study, by calibrating the modified Ibarra-Krawinkler deterioration model parameters for steel plate shear walls with different properties, some equations are proposed to determine modified Ibarra-Krawinkler deterioration model parameters. First, one of the experimental specimens was modeled and analyzed in ABAQUS software and accuracy of results was measured. Then, 60 number of pinned joints-one story steel plate shear walls with different infill plate thickness and bay length, using two types of steel for infill plate are numerically modeled and analyzed by ABAQUS software. Also, the height of steel plate shear walls was kept constant equal to 3500 mm. Using OpenSees software numerical analysis results, the modified Ibarra-Krawinkler deterioration model parameters are calibrated. Then, by identifying the effective factors, some statistics equations are suggested. According to the results, effective parameters on lateral load resisting capacity, elastic stiffness and post capping stiffness were thickness of infill plate and its steel type and ratio of bay length to height of steel plate shear wall. Also according to the results, the and ratio of bay length to height of steel plate shear wall had more influence on modified Ibarra-Krawinkler deterioration model parameters.

In the conditions of acid rain, chemical reactions occur in the concrete structure, which leads to a change in pH. When these reactions continue, concrete begins to lose its mechanical strength, which leads to cracking, weight loss, and finally the destruction of the structure. Since the control of acid rain and its effects on the surrounding environment is unavoidable in some cases, so far researchers have conducted many studies on this category and have provided solutions to eliminate or control its effects. One of the new solutions in this field is the use of nanoparticles. In recent years, studies have been focused on silica nanoparticles, with the aim of increasing the properties of concrete by using this material. Adding nano-silica to concrete in non-acidic (neutral) conditions reduces water permeability in concrete and also increases resistance against chemical attacks. In this article, the mechanical characteristics and durability of concrete containing nano-silica, including weight loss, compressive strength, electrical resistance, and water absorption rate under acidic conditions are investigated. According to the obtained results, with the increase of nano-silica in concrete, the mechanical properties and durability of concrete improve, but with the increase of water acidity, the durability and mechanical properties of concrete decrease.

In recent years, self-compacting mortar is widely used in various parts of construction projects due to its high efficiency. The efficiency of self-compacting mortars depends on the composition used in the mixing plan and the characteristics of its components, such as the type of aggregates, super-lubricating quality, additives, etc. Also, to improve the properties of cement mortars, the use of additives such as fly ash, nano particles, etc. has become popular. Considering the importance of examining the mechanical properties and efficiency of cement mortars, in this study, the effect of microsilica and super-lubricant on the efficiency and compressive strength of self-compacting mortars has been investigated. The research results show that the addition of microsilica increases the compressive strength and reduces the small slump flow in the mortar. Also, the ratio of water to cement is one of the important parameters in increasing the short-term compressive strength, which has a greater effect than other parameters, and by reducing the ratio of water to cement, more compressive strength was obtained.