Showing 32 results for Subject: Special
Mohsen Zahedi, Ali Zarei, Yahya Adineh Far,
Volume 1, Issue 1 (9-2017)
Abstract
The use of various additives including polymer additives to modify the properties of bitumen used in road pavement construction was crucial for researchers to use modified bitumen in the asphalt significantly increased pavement and operational life of them. Accordingly, in this study the effect of lignin derived from waste paper companies Chukka (Wood and Paper industries of Iran) on the performance of bitumen based on laboratory practices have been investigated. Lignin including natural polymers that in the paper production process must be separated from the texture of wood, so papermaking waste treatment plants to be found in large quantities. In this study different weight percentages of lignin polymer (3, 6, 9 and 12%) has been mixed with bitumen 60-70 Isfahan refinery and its impact on the various properties of bitumen was studied. Add this polymer improves the performance characteristics of the bitumen at high temperatures. Increasing lignin reduces the penetration grade, increase viscosity, increase rotary viscosity and softening point of bitumen. Also by increasing lignin, bitumen thermal sensitivity is reduced which indicates better performance is bitumen for road construction.
Mohammad Zarei, Farzad Akbari Nia, Ali Zarei, Hamed Azad Manesh, Mohsen Zahedi,
Volume 1, Issue 1 (9-2017)
Abstract
The main network of roads of the country is asphalted pavement. Finding a way to improve the technical properties of asphalt has attracted the attention of experts in recent years. Nanomaterials can be used to improve the technical properties of asphalt. On the other hand, fibrous materials can also be used to arm the asphalt mix. In this context and in this article by adding different percentages of nano-carbon black marshall experiments, analyze data and plot it was noticed that the addition of these additives increases the resistance of marshall and decrease of flow. On the other hand, resistance was increased by adding industrial polyester fibers to asphalt mixtures and in low percentages. Psychosocial rose as the percentage of industrial fiber polyester increased. Other results also changed. Economically, the results indicated that the use of fibers in general is preferable to nano-materials and its use in asphalt mix is recommended. Finally, by comparing the results, it was concluded that the blend containing black nanocarbon is more rigid than the mixture containing industrial polyester fibers, and it can be used in the regions with tropical weather and so much traffic and with more traffic and limited use.
Hamidreza Ashrafi, Peyman Beiranvand,
Volume 1, Issue 1 (9-2017)
Abstract
The effect of shape memory and super-elastic property are two exclusive features in shape memory alloys. In order to exploit the properties of shape memory effect, alloy needs to be heated but super-elastic property in these alloys will be proposed automatically in case suitable conditions. In case of using shape memory alloys as Longitudinal armatures in reinforced concrete structures considering them buried in concrete, exploitation of shape memory property will have its particular problems that these problems won’t happen about super-elastic property. Considering the high rate of strain capacity 3% to 8% in memory alloys with super-elastic behavior and the limitation of this capacity in concrete, conditions are necessary to be prepared in a way that memory alloy has the opportunity to propose super-elastic property. In this study, with simulating short-square reinforced concrete column experimental model in software ANSYS and in multi-level and increasing process, longitudinal armatures with shape memory alloy material will replace steel armatures with super-elastic behavior will be investigated with making shape memory alloy kind as variable (Copper and nickel-based alloys), the opportunity of super-elastic property emergence in these alloys and with playing the role of longitudinal armature in reinforced concrete column.
Farzad Akbari Nia, Mohammad Haji Jafari,
Volume 1, Issue 1 (9-2017)
Abstract
The VMS is one of the most effective tools in the field of intelligent transport systems, which in addition to the graphical representation of the traffic situation, can provide an appropriate notification platform for essential messages to users. For this purpose, in this paper, introducing the effective parameters in selecting the optimal placement of news message boards with the aim of maximizing the efficiency of this equipment in the distribution of traffic in urban roads, ARCGIS software has been used for this purpose. In this regard, by simulating the city-wide interurban network of Karaj in the software and defining the parameters involved in location selection, it is suggested that the locations are located, while in the optimal visual position, considering the volume of traffic, the decision-making power of users in choosing Other paths are provided after crossing the board.
Manouchehr Basati, Said Saidi Jam,
Volume 1, Issue 1 (9-2017)
Abstract
The main reason of mortality at many roadways of the country is the accidents of heavy vehicles. These accidents cause creating high costs. Lorestan province is the passageway of many heavy vehicles due to its geographical location and being located on the border of the other industrial provinces such as Khoozestan , Markazi, and Esfahan and traffic of such vehicles is very high in the main roads of this province. According to the analysis conducted on the reported accident between the years of 92-93 , the amount of the blamed heavy vehicles increased by 10.69 percent had the highest growth and the fatal and injury accidents of these kinds of vehicles have increased respectively by 6.24 and 14.76 percent. There fore, considering some special measures for controlling the heavy vehicles seems necessary. This research has been provided based on the information and Com 114 records which were recorded by the police of Lorestan province and the analyzes have been performed by using SPSS software. The results of analyzes of heavy vehicle accidents have shown that the axes of the province and a major cause of accidents of this type of vehicles in summary are: 1. Failure to observe the right of way, paying attention to the front, the inability to control vehicle and assault and deviation to the left as the most important factors leading to the accident. 2. collision with a vehicle as most types of accidents 3. overturning, rear-end collision accident occurred and most of the accident 4. drivers aged 25 to 35 years as a high risk group for heavy vehicles Tsadafat 5. Category education diploma and diploma below the literacy level of most of the drivers at fault in the accident 6. The second half of the day as the time when most accidents.
Mohammad Barati, Mohammad Zarei,
Volume 1, Issue 1 (9-2017)
Abstract
Asphalt, this wonderful mixture that all of us deal with it every day. Perhaps the engineers in this domain as one of the solution have placed the modification of technical properties of asphalt on top of their activities for improvement of the features of this wonderful mixture. Modifying the technical properties of bitumen and asphalt has created many study opportunities all around the world. Along with it and in this article at first, with adding carbon nanotube with the amounts of 0.25, 0.50, 1 and 1.5 weight percent of base bitumen, the effect of this additive on mechanical properties of asphalt mixture was studied. In the continuation, the asphalt samples amplified with carbon nanotube for doing the Marshall Test were evaluated and tested. The results indicated that this additive causes to change in the Marshall test parameters such as increase of strength and reduction of flow. On the other hand, the special weight of asphalt mixture has faced with increase and the void space percent of aggregates faced with relative reduction. Also the void space percent of asphalt mixture and the percent of void space filled with bitumen were increased relatively. In the economic study of the effect of carbon nanotube on mixture, it was concluded that with gradual increase of carbon nanotube, the economical advantage of the project is reduced. Finally, with regard to the obtained results and analysis of the effect of this material on the bitumen and asphalt properties, it was concluded that this additive can be used in the regions with warm climate with heavy traffic and in the limited regions.
Korous Nekoufar, Maryam Saghafi, Mehrnaz Roozbahani,
Volume 1, Issue 2 (12-2017)
Abstract
The problem of erosion control and sedimentation in rivers has long been considered by humans. Every year a large number of bridges and flood in the river, at a time when they are most needed, are destroyed. One of the most effective agents of this destruction, scour around the base of the bridge, which creates a lot of human and financial losses. vanes submerged and non-submerged, structures that are at the bottom of the river with an angle to the main flow and in order to prevent the erosion of as rivers and screws and the base structure and morphology of the water and the river bed are correct. The secondary vortex structures cause's changes in the flow pattern of the river bottom sediment and erosion are the result of the transition. System, number, space, geometry and angle of the screen can be effective in the sediment of the front legs. Understanding the flow field plates can help engineers to better use them in rivers. So, in this thesis examined the effect of submerged vanes on the cylinder of the river has been using the software SSIIM and in this regard the placement of three vanes is studied in this research.
Behzad Haseli,
Volume 1, Issue 2 (12-2017)
Abstract
One of the influential factors in the response of the collapse of the bridge and the collage is its modeling. Seismic behavior analysis and bridging modeling are usually performed using simplifying assumptions. This simplification may lead to major changes in the prediction of bridle shaking behavior. In this research, the collapses in three general modes of modeling under the influence of earthquake records in the near field (due to the occurrence of the critical behavior of the bridge under the influence of near-field records in comparison with the far-field domains) were analyzed by nonlinear time-based analysis method in SAP 2000 software and the results in scenarios Different collage modeling is compared. Of noteworthy points in this study is the modeling of the shells as a wall base and the equivalent hardness calculation using static pressure and dynamic pressure of the back of the collar. The results of the analysis show that the modeling of the end nests in addition to the bridge displacement on other seismic parameters including axial force distribution, bending anchor, anchor response, and base cutting effect, in such a way that the results represent the maximum difference of 78% in the longitudinal displacement of the end nests , The 90% difference in the central axis force and the 82% difference in the bending relationship between the middle base based on the collage modeling is simplified, compared to the modeling of the collage as a roller. On the other hand, the results of studies in this study show that with the height of the back of the knoll in the range of 4 to 9 meters in height, with acceptable accuracy (the difference of responses is 29% to 13%), the collateral modeling can be replaced in the base form of Diviara Designed for modeling the shell according to the Caltrance directive (2013).
Farzin Farooghi,
Volume 1, Issue 2 (12-2017)
Abstract
In these studies, the effect of the load types on the stress and the deformation created in the hot-mix asphalt and its lifetime in different qualitative conditions of the surface contact of the layers has been investigated. For this purpose, we have used a set of rules in Iran and France codes. In Iran, the weight of the single-axle load 80 kN and in the French Code the weigh of the dual-axle load is 130 kN. Linear elastic method has been used in structural analysis and fatigue failure and rutting failure has been used to investigate the lifetime of structure. In these studies, the effect of the layer thickness and the two types of contact surface quality (adherence and Non-adherence) are considered. One of the most important results of this study is the significant increase in the vertical strain of the subbase course and horizontal strain of the base course due to single axel load compared to the dual axel load. Inappropriate quality of the layers has increased about 50% of the settlement in the pavement. Also, the effect of single axle load increased about 45% of structural settlement and decreasing of the base and surface courses thicknesse has increased about 30% seattlement in the pavement structure.
Fatemeh Rahimi,
Volume 1, Issue 2 (12-2017)
Abstract
At this paper, Non-linear FE models were used to stimulate strengthened deep beams with opening. Since the regulation, the analysis and designing of deep beams with opening in truss model has doubted, so FE models are the best option in terms of deep beam behavior. One web opening do not turbulent loads transfer path, whereas deep beams with 2 opening can clip the path of strut and decrease shear capacity. The comparison between experimental results and FE model with the ACI outcome, are representing accurate modeling in RC deep beams. Parametric analysis results indicate, when opening cut the strut path, shear strength will be limited. Specimens were retrofitted in perpendicular direction to plastic strain had the most shear strength.
Mohammad Rezaei, Ebrahim Khalilzadeh Vahidi,
Volume 1, Issue 2 (12-2017)
Abstract
Self-sensing concrete (ISSC) refers to a structural material that can be monitored without the need for a sensor or remote control. By measuring the electrical resistance of the ISSC, stress, strain, cracks and damage can be monitored in situ. Compared to conventional structural materials that require additional sensors for monitoring or tracking, ISSC has the advantage of: high sensitivity, good mechanical properties, natural compatibility, durability, easy installation and maintenance. The ISSC can be used to monitor structural health, tracking traffic and border and military security. In this paper, we describe the ISSC research advances in terms of its composition, construction methods, sensory signal testing methods, sensory properties, and manufacturing mechanism and structural applications. future challenges in the development and application of ISSCs will also be discussed.
Majid Abdollahi, Fereydoon Khosravi, Sayyeid Hamed Khalilpor,
Volume 1, Issue 3 (3-2018)
Abstract
A significant portion of the world's energy consumption is spent on heating and cooling, which will increase the demand for energy efficiency improvements. One of the ways to improve energy consumption in buildings is the thermal design of various building components, including walls, ceilings and floors, in accordance with the requirements and principles set forth in the regulations. The main objective of this research is to provide a comprehensive comparison of all types of building insulations and familiarity with the design principles of their construction based on the requirements of section 19 of the National Building Regulations of Iran. In the present paper, after introducing various insulators, five criteria including density, thermal conductivity coefficient, fire resistance, resistance to sunlight and sound properties of insulators have been investigated and compared. In the end, a case study is conducted to get familiar with the thermal design process for a residential building in Tehran. The results show that a thickness of 5.5 cms for rock wool (regardless of the thermal resistance of other layers of the wall) will fullfill the thermal design requirements.
Esmaeil Addollahzadeh,
Volume 1, Issue 3 (3-2018)
Abstract
Appropriate selection of road pavement maintenance options is economically an important process in the pavement maintenance management system. Using appropriate and reasonable models for economic judgment on periodic maintenance Alternative is an important and important point within the framework of the pavement management system, which analyzes the cost of life cycle of one of these methods. On the other hand, the study of failure indicators to identify the weaknesses of communication routes, in addition to improving the transport situation, can lead to preventing bad and bitter driving accidents. In this research, the input information required by RUCKS software was first provided and the basic values for the cost components of users were obtained, then the results of this software, along with other inputs required by Real Cost software, were compiled using Lifecycle cost analysis method, economic evaluation on the periodic options of pavement maintenance and maintenance has been introduced. In this study, the PCI index was used to investigate the structural integrity of the pavement and to achieve the pavement failure status. In order to apply the present research, the Gorgan-Kordkuy axis has been studied and evaluated, and all the parameters introduced in the Gorgan-Kordkuy axis have been presented. The results of the study show that failures in the Gorgan-Kordkuy axis can lead to irreparable damage over time as a result of non-refurbishment and restoration.
Amin Faghrian, Akbar Ghanbari,
Volume 1, Issue 3 (3-2018)
Abstract
Explosion phenomenon has been most attractive subject for researchers during different era, from innovation of gunpowder to these days. The biggest of these researchers has been done during WW2. At last years, many terrorist attacks have been done by using explosion materials and bombs. Explosion is a chemical reaction; it finishes in some mill-second. During reaction a huge amount of energy release in the atmosphere and cause a pressure wave by high speed. Wave attacks building, impacts and forces them. In general, RC buildings have better reaction to explosion wave, because of their high mass. In this study, main goal is to observe the RC building under explosion load and finding ways to reduce or prevent damages. To model the RC building the ABAQUS Finite Element software has been used. For modeling it has been tried to make the model very close to the reality and to cover the proper details. The results show that distance has significant effect on reducing the explosion wave pressure and consequently on applied explosion loading.
Iraj Bargegol, Vahid Najafi Moghaddamgilani, Afsaneh Tahriri Amlashi,
Volume 2, Issue 1 (6-2018)
Abstract
The time values of the saturation flow rate in signalized intersections play a key role in their schedule, and performance. So far, studies have been done to estimate average discharge headway of the nearside legs of intersection. While its values are not the same as far-side legs due to the number of lines, driver behavior and other physical characteristics. In the present paper, with the help of field data acquisition at five signalized intersections in Rasht city. Then estimated and compared the values of the time of discharge and delay time in the nearside and far-side legs of the signalized intersection. The results show that saturation conditions occur between the second and last vehicle in the far-side legs and between the fifth or sixth vehicle in nearside legs intersection. In other words, the number of vehicles with start-up delay is 1 or 2 vehicles and 4 or 5 vehicle in the far-side and nearside legs respectively. Also, the amount of saturation headway of far-side legs is less than the nearside legs.
Shahrad Nosrati, Ehsan Alvani, Mehdi Haghighi, Pooya Naseri Alavi,
Volume 2, Issue 1 (6-2018)
Abstract
In this study, factors of human resource planning, human resource development as well as their impact on yield was evaluated. To achieve this goal, the population of engineers, contractors, employers and consultants were selected from the community, 70 companies cooperated with the investigation. In this study, a questionnaire was used and the results of the questionnaires were analyzed by software SPSS and EXCEL. The results showed that in the implementation of human resource management in a transparent and proper planning, the basic parameters of the project, organizational and managerial capabilities, personal development, group performance, technical performance and creativity, as well as business performance with average coefficients of the 3.8 as well recover.
Mohammad Javad Taheri Amiri, Maedeh Javaheri Barfrooshi,
Volume 2, Issue 1 (6-2018)
Abstract
Monitoring and evaluation are of utmost importance, so that without the creation of a coherent and well-established system, will not have a remarkable efficiency. These oversights are targeted to improve and promote the projects / plan execution quality in the organization while utilize the knowledge and experience of specialists in enhancing the researchers’ activity. Today, the construction sector is encountered many disruptions including low quality constructed buildings. In order to cover the technical inspection services of the building, there is a specific oversight on construction, based on rules and regulations on building subjects. However, due to the number of decision-making centers on building standards such as Construction Engineering Organization, Institute of Standards and Industrial Research, Municipality, and the Ministry of Roads and Urban Development, the supervision and technical inspection of the building sector are in difficulty. In this research, firstly, FMEA method will be used to identify and prioritize the factors affecting the monitoring difficulties in the construction projects of Iran. Then, in order to prevent these problems from occurring in the country's construction projects, some course of actions are presented.
Sina Rezaei, Saman Fathi Koche Tala, Ali Naseri,
Volume 2, Issue 1 (6-2018)
Abstract
In a general category, it is possible to divide the various irregular types of structures in height into two irregular geographic and nonlinear groups. In a geometric disorientation at elevation, the dimensions of the structure plan are significant at significant altitudes. In non-horizontal non-uniformity in height, sudden changes occur in the dynamic properties of the structure, including mass, stiffness and lateral resistance of the structure at height. Progressive breakdowns usually lead to a partial collapse of the entire structure, extending a primary damage within the structure, which is like a chain reaction. Studies on structural system failures In recent years, the importance of the phenomenon-failure phenomenon due to abnormal loading due to sudden damage, earthquake, explosion, earthquake, and so on. In this study, four steel structures with a dual-side duct frame, a special bending frame and specially designed 5, 10, 15, and 20 Story collimator brackets were designed in Etabs 2016 software. Then, using the US Department of Comprehensive Maintenance Manual and the method selection The alternative load transfer route, the well-known structures in OpenSEES software is modeled 3D and uses neonotope dynamic analysis to investigate the irregularities of the damping of the perpendicular system on the structural behavior of the seismic behavior in the progressive failure. After analyzing the results of the analysis, it was observed that the irregularity of the cutoff of the lateral load system reduced the structure and stability of the structure and reduced the structural strength against progressive failure.
Mehdi Atayi, Fereydoon Rezaei,
Volume 2, Issue 2 (9-2018)
Abstract
In an analysis of the seismic behavior of a structure, an excitation applied from the ground to the structure for the case where the structure relies heavily on the earth, it is the same stimulus that existed before the construction of the structure at that point of the earth, However, if the structure depends on the soft soil, significant changes will occur in the seismic input of the structure . Therefore, the structure with the surrounding soil will be in operation and will make changes in the base movements Consequently, taking into account the effects of interaction between the soil and structure can accurately increase the natural periodicity and thus reduce the coefficient of earthquake in design and consequently reduce costs. In this study, the resonant coefficients of displacement of fifteen flexural concrete frame with shear wall were resilient and non-reactive analysis. The studied frames are varied in the number of 5, 10, 15, 20, and 25 in 5 openings And the effect of the soil-structure interaction on the magnitude of the displacement coefficient and its comparison with the stationary foot state has been investigated. Each frame was modeled using nonlinear static analysis using the SAP2000 software . The Springer Wincher method has been used for substructure soil model. The results show that the magnitude of displacement coefficient in states with regard to the interaction of soil and structure is higher, regardless of the interaction of soil and structure.
Tina Jalalzadeh, Majid Barghian,
Volume 2, Issue 2 (9-2018)
Abstract
Earthquakes are the major cause of bridges destruction. It is obvious that the seismic ability of bridges and in general all transportation systems are very important in management of crises. For this reason, the seismic performance and behavior of particular types of bridges have been researched in this study. Skewed bridges are most popular and applicable in the design of highways and inter-city roads. Wherever roads cannot be continued straightly, bridges and in some cases skewed geometry of the bridges are practiced. The design of this kinds of bridges has become a normal practice within engineering communities in recent decades with emphasis on the construction of pre-stressed skewed box-girder bridges due to their characteristics and behavior. In this study three-span pre-stressed box-girder bridges with different skew angles were modeled using CSiBridge software. Seismic analysis was performed on the above-mentioned bridge with different skew angles and demand to capacity ratios for columns and internal forces of deck and columns were extracted from program to find out the general behavior of structure. Results indicate that increasing the skew angle of the bridge decreases the capacity ratio of the columns. An increasing trend is observed for the axial force of columns when increasing the skew angle in first bent columns while the converse is true for the second bent. Shear force in longitudinal direction of the bridge for columns tend to decrease while an increase is noticeable in the transversal direction in first column. Torsional moment in first bent rises in contrast to that of the second bent which declines. Bending moment about transversal axis decreases. For internal forces of deck with increase of skew angle the axial force increases, vertical shear force at beginning of bridge (obtuse corner) increase and at the end (acute angle) decrease. This force reduces on bents and increases in the middle of the bridge. The torsional moment of deck at beginning of bridge increases and at the end of bridge decrease, and at the middle increases. Transversal bending moment of beginning and the end of the bridge decrease and it is increased on bents and in the middle of bridge. Longitudinal bending moment at beginning, end and on bents of bridge decrease and on the middle of bridge increases.
