جستجوی مقالات مرتبط با کلیدواژه "w" در نشریات گروه "عمران"

In recent years, the surge in pollutants from fossil fuels has prompted a heightened emphasis on transitioning to clean and renewable energies, with a particular focus on wind power. The deployment of offshore wind turbines stands out as a prominent approach to harnessing wind energy. However, these turbines consistently endure cyclic loading induced by wind, waves, and ocean currents, necessitating foundations that exhibit robust resistance to such repeated stress. Offshore wind turbines are commonly mounted on monopiles, singular tubular structures with diameters ranging from 2 to 8 meters. While these turbines were initially deployed in Europe, their utilization has expanded to seismically active regions such as USA, China and Japan in recent years, owing to their numerous advantages. As a result, their seismic behavior has become a subject of interest. The seismic design of these turbines, similar to other structures, should be based on past earthquakes in the region and adapted to saturated conditions. Until now, a multitude of studies has delved into these turbines, predominantly through numerical research. However, the scarcity of experimental investigations into their seismic behavior has left the impacts of acceleration and frequency of input motion on their design not thoroughly explored. Furthermore, in certain instances, the design of these turbines makes reference to regulations designed for dry conditions. This research investigates the impact of acceleration and frequency of input motion on the seismic response of offshore wind turbines through 9 experiments conducted on samples using a 1g shaking table. Various input motion with different acceleration and frequencies were applied under both dry and saturated conditions, allowing for a comprehensive comparison of turbine behavior. The modeling process included creating a soil environment with specific dimensions through dry deposition and compaction, followed by the embedding of sensors for measuring acceleration and pore water pressure. After these initial steps, the monopile was vertically drove into the soil, and the superstructure was assembled. Displacement sensors were installed to capture the superstructure's displacement at different heights and to measure the settlement of the soil surface on the samples. Then the sample started to be saturated from the bottom of the box and water was placed on the soil surface up to 10 cm to model sea water. Subsequently, harmonic sinusoidal loading was applied, with 9 loadings featuring frequencies of 10 Hz, 5 Hz, and 3 Hz, along with maximum accelerations of 0.2 g, 0.3 g, and 0.4 g, respectively. As indicated by the findings of this research, turbine seismic behavior becomes significantly more critical during resonance phenomena in the most critical state, with the impact of other factors on seismic performance proving negligible in such instances. Moreover, the seismic behavior of these turbines consistently exhibits more critical behavior in saturated conditions compared to dry conditions. In saturated conditions, acceleration amplification in surface soil layers is up to 5 times, profoundly influencing seismic performance, whereas in dry conditions, amplification is limited to 1.2 times. Additionally, as excitation acceleration rises and excitation frequency decreases, the superstructure's maximum acceleration and the turbine's maximum and permanent displacement all increase, signifying a more critical behavior of this structure.

Prior research has not explored the creation of concrete with superior thermal insulation properties using calcium oxide-activated materials. Furthermore, the impact of substituting large proportions of sand with worn rubber powder and PET on the mechanical and thermal characteristics of high-performance geopolymer concrete remains uninvestigated. This study addresses these gaps by examining the development of geopolymeric concrete with enhanced thermal insulation properties using calcium oxide-activated materials. A novel mixing method has been devised to improve the compaction of thermally insulating concrete, which includes calcium oxide-activated slag. For the purposes of this research, worn rubber powder and PET powder have replaced 10%, 20%, 30%, 40%, and 50% of the aggregates. The mechanical properties of the concrete were determined through compressive strength, four-point bending, and tensile strength tests. Lastly, the thermal conductivity coefficient was tested to ascertain the thermal properties of the developed concrete.The findings revealed that in the developed concrete, substituting 10% of the aggregates with worn rubber powder or PET powder increased the energy absorption capacity of the concrete by 143% and 107%, respectively, while its mechanical properties decreased by 10% and 7%, respectively. Moreover, using 50% worn rubber powder and PET as aggregate substitutes reduced the samples’ thermal conductivity by 70% and 60%, respectively.

Recently, the modification of bearing capacity and the reduction in settlement of existing foundations and buildings has become one of the important topics in the field of geotechnical engineering. Also, the foundation of the buildings on the problematic and flowing sand bed, especially in the coastal strips is inevitable. In general, when faced with problematic soils such as loose soils with low load-bearing capacity, high settlement, liquefaction, disturbed soils, etc., there are two ways for geotechnical engineers, one of which is to use bearing elements in the soil and the other is to improve and modify the physical-mechanical properties of the soil mass. In addition to acting as a bearing and settlement-resistant element, the micro pile also improves the bearing strength of the surrounding soil due to the injection of cement slurry. In many projects, micro piles are used as structural elements. In fact, micro piles are small replacement piles (usually less than 300 mm in diameter) that are often accompanied by steel reinforcement and cement grout injection. Micro piles can be designed and used at any angle and for different purposes, including bearing axial and lateral loads, replacing conventional piles, or as part of a soil-pile system, depending on the purpose of the design. In this study, by physical modeling, the effect of using micro piles on the edge the foundation on sand bed was investigated. For this purpose, the effect of the boundary conditions of the chamber was first investigated. The parameters included the width of the foundation (B), the distance of the foundation from the end surface of the tank (Z), the distance of the foundation from the right/left wall of the chamber (X, X'), unreinforced bearing capacity (Q0) and unreinforced sand settlement (S0). Also, the investigation of the effect of the distance of the foundation from the lower surface of the steel chamber to the width of the foundation (B) showed that when the distance of the foundation from the lower surface of the chamber was less than twice the width of the foundation, the lower boundary affected the results of physical modeling. The evaluation of the lateral boundaries given the distance of the foundation from the chamber wall (X) to the width of the foundation showed that for X/B≥5, the lateral boundary had no effect on the results. Influences of various micropile skirt configurations were investigated, including micropile length (L) and spacing between two consecutive micropiles (S) on bearing capacity-settlement. The micropile skirts improved the bearing capacity of shallow foundations, depending on the L/B ratio and spacing between micropiles depending on the S/D ratio. Analysis of the results indicated that improved bearing capacity upon increasing the length of micropile skirt and reducing the spacing between two consecutive micropiles. Comparison of the pressure-settlement curves showed that in constant micropile lengths, the optimum Bearing Capacity Ratio (BCR) was in S/D=2. Further, the skirt piles reduced the settlement of strip footing. The Micropile Skirted Strip Footing (MSSF) led to increased failure surface and, depending on the pile length and spacing micropiles, it changed the failure pattern of the soil.

Retaining structure or retaining wall is a wall that acts as supporting structure and the stability of another structure. This wall is used for preventing collapse of soil and generally wherever lateral support is needed. The retaining wall can be designed as gravity, cantilever and supported. Considering that the retaining walls are essential in protecting the related structures to them, therefore, studying the dynamic behavior of these structures is very important due to the financial and human damages. Such structures should be stable against the forces acting on the wall. In addition to static loads, which are always an inseparable part of the calculations of such walls, forces such as cyclic forces caused by the movement of machinery and also dynamic forces caused by earthquake occur on the wall during the period of operation. These forces can be effected on retaining walls and should be investigated and evaluated. Trying to investigate and analyze the dynamic behavior of different retaining walls is one of the most challenging for different researchers. The wavelet theory in the dynamic analysis of the issues related to civil engineering is going to be widespread. This research aims to investigate the effect of using wavelet theory in the dynamic analyses of concrete retaining walls. For this purpose, a soil medium along with concrete retaining walls with different dimensions (heights) are considered. Dynamic analyses are performed based on the finite element method. In the first stage of modeling, the Sarpol-e Zahab earthquake record is filtered during four steps using the discrete wavelet theory. The numerical models are prepared and subjected to the available records. The percentage of the difference in the results of the analyses done with the records obtained from the different steps of filtering record with wavelet compared to the analyses done with the main record, along with the reduction of the time consumption, is evaluated. As expected, the best match of the post-filtering results to the main earthquake results is for the first-step filter. It can be seen that even the first step filter reduces the analysis time by about 60%. Based on the obtained results, the difference between the results obtained with the filtered records becomes less compared to the main earthquake with the increase in the height of the wall. It has also been observed that acceptable results are still obtained, and the analysis time is reduced by almost 80% until the third step filter. It should be noted that the Mohr-Coulomb behavioral model is used in the conducted analyzes in this research. This behavioral model is not inherently able to model hysteresis damping behavior at low strains. Therefore, this issue can affect the results of deformations and stresses obtained from dynamic analysis. However, the purpose of this research is to evaluate the performance of the wavelet in the dynamic analysis of the retaining wall. Considering that in all the analyses (both the performed analysis with the main earthquake and the performed analyzes with the wavelet filtered records) the same structure and trend are used, it can be concluded that the effect of using the wavelet compared to the main earthquake gives an acceptable overview and quality

Most of the noise pollution in big cities is related to traffic, and the construction of highways and traffic flow with high volume and speed creates problems for the nearby residents. Calculating the amount of noise pollution through modeling makes it possible to reduce the effects of noise pollution in the design of highways and surrounding uses. This research, which was conducted on the Hashemi Rafsanjani highway (Misthaq) in Mashhad, by measuring the volume of sound, traffic information, weather information and surrounding uses, using the American federal highway management model (FHWA) with TNM 2.5 software models the emission of noise pollution and compares the obtained results with the measurements made through statistical analysis. The following steps were implemented for this research: 1- collecting information about the volume and speed of traffic, 2- collecting information and characteristics related to the road such as road width, road type, surrounding land use map, green space around the highway, height and density of buildings around the highway, meteorological information such as temperature and humidity, 4- determining sensitive points around the area in terms of noise pollution, such as residential, medical, educational centers, etc., and measuring sound in sensitive points as sound receptors, 5- modeling by TNM 2.5 software, AutoCAD map or GIS layers for the scope of the project should be prepared and converted to DXF format, 6- statistical analysis and comparison of the results obtained through the model and measurements and comparison with the standards, and 7- testing the hypotheses through SPSS statistical software and analyzing the results in the Excel environment. The estimated results of the FHWA model were very close to the observed values (The highest value is 85 db and the lowest value is 55 db), therefore, according to the results of this model, it is reasonably accurate for predicting noise pollution, and the average difference of the Leq values ​​calculated with the measured values ​​is ±3.5 dB. The regression coefficient between the measured values ​​and the values ​​calculated by the model was reported as 0.685. The amount of difference of the predicted values ​​is relatively high only in three stations 1, 7 and 24 and is equal to 14.8, 10.7 and 10.7 dB respectively. In examining the cause of this issue, it can be stated that two stations 1 and 7 are located in a position where, in addition to the sound they receive from the studied highway, they are affected by the traffic of vehicles on other routes near them and receive sound. In the study area, due to the fact that the majority of uses are residential, which is considered as a sensitive area, all measured values ​​in the stations were higher than the standard of the Environmental Protection Organization (55 db). The lowest recorded sound is related to station number 36 with a level of 55.4 dB. This station is located inside the barren lands and is connected to the agricultural lands located between Amirieh and Esmatiye boulevards. The average amount of noise pollution in all stations is 74. The highest sound value is related to station number 24 and is equal to 85.1 dB, which is located at the beginning of Hashemi Street 45 and the dominant use around it is residential. Due to the large number of vehicles, including cars, heavy vehicles, buses, semi-heavy and motorcycles, all areas show high noise pollution that can endanger the health of citizens. The effect of car type was investigated by Pearson's test, and there was the highest correlation between motorcycles and noise pollution, as the number of motorcycles increased, the value of the two noise indices LAeq and LAFmn increased with correlation coefficients of 83% and 84%. In this regard, it is necessary to take necessary measures such as replacing with new electric motorcycles. Allocation of land around highways to sensitive uses, including medical and educational centers, has not been approved, and the effects of noise pollution can be reduced through appropriate planning. There are several solutions to reduce the effects of noise pollution, based on priority, it is possible to correctly locate the uses, consider the distance between highways and sensitive uses, assign this distance to uses such as linear green space, footpaths and bicycles, the creation of barriers that reduce sound waves such as embankment, trees and finally the last priority of using technical equipment such as acoustic wall.

Reduced Beam Section (RBS) connections are extensively used within seismic resistant steel moment frames in order to deal with the risk of brittle fractures in the connections, absorbing seismic energy through yielding and protect columns from damage. In this connection, at specific locations the beams flanges are trimmed back to provide weakened sections, in order to shift the plastic deformations away from beam-column connections and into the beam. Consequently, adequate ductility is provided by the frame to absorb the seismic energy and avoid the risk of brittle fractures occurring. The seismic performance of steel structures has been studied widely by many researchers. In general, the results of these studies indicate the good capability of RBS connections achieving these targets. In a reduced beam section (RBS) moment connection, in the region adjacent to the beam-to-column connection, a part of the beam flanges is trimmed selectively. Yielding and hinge formation are intended to take place primarily in the reduced section of the beam. Currently, in the design of RBS connections, the effect of RBS cutting parameters on the cyclic performance of the beam elements are not taken into account. However, using different RBS geometries for any beam with different sections can have different results in cyclic performance of the connections. In order to evaluate the effects of geometric parameters of RBS connection on the cyclic behavior of these connections, a parametric study is carried out on forty different European I-shaped steel cross-section specimens. These specimens are analyzed using ABAQUS finite element software under cyclic loading and the moment-rotation hysteresis curve was extracted for each of the specimens. In order to validate the FE model, a full-scale beam–column sub-assemblies were modelled in the general finite element (FE) software ABAQUS. An ideal curve was extracted from each of the hysteresis curves and using the curves, five parameters including Yield Moment (My), Peak Moment (Mc), Ultimate Rotation (θu), Ductility (μ) and Energy Dissipated Capacity (EDC) were extracted as the key design parameters for each sample. variation of the above-mentioned seismic design parameters in respect to the changes of RBS dimensions are analyzed. The results clearly illustrate that geometric features c do have most effect on the moment parameters. the parameters a and b have very little influence on moments which can be considered negligible, whereas these parameters have a small effect on the ultimate rotation, ductility and energy dissipated capacity. Increasing the value of c between its lower and upper limits, reduces the My more than 20% and Mc more than 17%. The effect of the distance of the cut area from the column face (a) and the length of the cut area (b) on the moment is close to zero and can be ignored. The effect of a and b on the ultimate rotation, ductility and energy dissipated capacity is less than five percent. However, the parameter c has significant influence over all the five seismic design parameters considered. Investigating the graphs of the variation of the key seismic design parameters respect to the changes of RBS dimensions shows that there is not enough correlation between the RBS parameters and the key seismic design parameters to propose a single equation between the key seismic design parameters and RBS parameters. Investigating the relationship between RBS dimensions, moment of inertia of RBS and full section characteristics showed that a relationship can be established between these parameters and the key seismic design parameters. At the end, the results of the investigation and relationships for calculating the key seismic design parameters were presented. This relationship was presented as a single equation, which includes the effect of all the above parameters. Using the obtained equation, the value of each of the key seismic design parameters can be calculated based on the dimensions and geometric characteristics of the section and the beam cutting dimensions.

Cyanide is a highly toxic and hazardous pollutant commonly found in the wastewater generated by mining, electroplating, and petrochemical industries. The current research aims to evaluate the efficiency of advanced oxidation techniques such as UV, O3, and UV/O3 combination, to eliminate cyanide from synthetic wastewater. All experiments were conducted in a semi-continuous reactor to investigate the impact of various operating conditions, such as initial cyanide concentration, reaction time, reaction kinetics, and pH. In this study, degradation tests were conducted on cyanide at four different concentrations (50, 100, 200, and 250 mg/L) and two pH levels (10 and 11). The reaction duration ranged from 0 to 90 minutes, with varying lengths. All experiments maintained constant operational parameters for the process, except for the variable being tested. The UV process alone is not very effective in removing cyanide from wastewater. This is because the low absorption coefficient of cyanide in the ultraviolet region limits the performance of UV in cyanide degradation. Additionally, cyanide is a relatively stable compound that requires a high amount of energy to break bonds and destroy them. Therefore, the use of the UV process alone is insufficient for the complete and safe destruction of cyanide from wastewater. It is necessary to combine it with other advanced oxidation processes to effectively remove cyanide from wastewater. According to the results, it was found that the effectiveness of removing cyanide through a single ozonation process was higher at pH 11 as compared to pH 10. The optimal conditions for achieving the highest level of cyanide removal, which is 68%, were found to be a single ozonation process with an initial concentration of 50 mg/L and a reaction time of 80 minutes. The higher efficiency of cyanide degradation at higher pH can be attributed to the greater production of hydroxyl radicals, resulting in an increase in the oxidizing power of the process. The efficiency of cyanide degradation in synthetic wastewater can be greatly improved by using the combined UV/O3 process. In this method, the rate of cyanide degradation is higher when the pH value is lower. This is because the integrated UV/O3 method is strongly dependent on the concentration of hydroxide ions and hydroxyl radicals, which are affected by the pH value. Therefore, the effect of pH value on the efficiency of cyanide degradation by the combined UV/O3 method is significant. When UV and O3 were combined, over 50% degradation occurred in 40 minutes due to increased degradation rate. The highest efficiency for cyanide degradation was achieved at pH 10 and an initial concentration of 50 mg/L using the combined UV/O3 method. The reaction time was 50 minutes and the efficiency was 100%. First and second-order kinetic analyses were conducted for UV, ozone, and combined processes to study their effectiveness in cyanide degradation. The results showed that the combination of UV and ozone was the most effective method for total cyanide degradation from wastewater compared to the other processes studied. Therefore, UV/O3 can be considered as the optimal analytical method for cyanide degradation from wastewater.

In this article, MMA which is a mathematical programing method is utilized for solving truss optimization problem. Although this method has been widely used in topology optimization problems of continuous structures, it has received less attention in the case of truss structures. The optimization problem considered here is the problem of minimizing the strain energy of the structure by considering the volume constraint. For the first time, the basics of the SIMP method and the application of the penalty exponent of the density function have been used for simultaneous optimization of topology and size of the truss members.To solve the optimization problem, analytical sensitivity analysis has been performed. Various problems have been solved at the end of the paper and the results have been discussed. The results show that if the appropriate penalty exponent is chosen, the correct optimal solution is obtained for the benchmark problems. Also, some more practical problems have been solved and the results have been discussed.

One of the common ways to increase the life of concrete is the use of pozzolans, some pozzolans that have higher reactivity than ordinary cement lead to greater resistance and less permeability of concrete by reducing concrete pores. Structures made with ordinary Portland concrete generally do not have proper performance in harsh environmental conditions and destructive aggressive factors. Sulfate attack is the process of concrete destruction due to the expansion caused by sulfate reactions inside the concrete, and in the long term, it causes a decrease in cohesion, occurrence of cracks and collapse in the concrete structure, one of the effects of which is the reduction of concrete strength. The addition of metakaolin reduces the porosity in concrete, as a result, concretes containing metakaolin have lower permeability compared to normal concrete. In this research, calcined clay was used as pozzolan, first the soil was heated to a temperature of 700 degrees Celsius for 3 hours so that the calcination process takes place, then calcined clay along with a percentage of limestone powder and microsilica was replaced by cement. The purpose of this combination for cement materials is to achieve a mixture design that the concretes made by it have better resistance than normal concretes against aggressive and corrosive environmental conditions. In this study, ettringite crystals were formed on the samples processed in sodium sulfate solution, which were less in the pozzolanic samples than in the control sample. At early ages, the capillary absorption coefficient for samples containing calcined clay is higher than the control samples, but this difference is greatly reduced as the samples age and the pozzolanic reactions become more complete. The electrical resistance values of the samples also increased with the passage of time and the increase in pozzolan replacement percentage. Also, in all the experiments, the addition of microsilica fills the empty spaces in the concrete, because the microsilica particles, being smaller than the pozzolan particles of the clay used and the faster reactivity of microsilica produces more silicate gel in a shorter period of time than clay pozzolan and makes the concrete denser. In this research, 10 mixed designs were used in 2 ratios of water to cement materials: 0.35 and 0.4. In each proportion of clay in percentages of 10 and 20%, limestone powder in percentages of 30 and 20%, respectively, and microsilica along with the combination of soil and lime in 7% by weight as powder materials were replaced by cement. In order to check the properties of the prepared soil, XRD test was performed to ensure the amorphousness of the soil particles and the presence of pozzolanic compounds on it. Also, to check and analyze the durability of concrete, sulfate resistance, capillary absorption and electrical resistance tests were used on 10 cm cube samples at the age of 28 and 90 days. In this research, designs containing 20% calcined clay, 20% lime, and 7% microsilica have the best performance in pozzolanic designs and are introduced as optimal pozzolanic designs in the conducted experiments.

The semi-closed geometry of the Persian Gulf and its location in a dry and desert area have caused evaporation as one of the most important climatic parameters affecting the water salinity and water exchange between Oman Sea and Persian Gulf. Since the global warming as well as the decrease of precipitation will increase the evaporation in future, it is very important to investigate the effect of this phenomenon on the salinity of the Persian Gulf and its effect on the facilities, especially the desalination plants in the Persian Gulf. Therefore, this research have been carried out with the aim of investigating the circulation of water in the Persian Gulf and evaluating the direct effect of water evaporation on salinity and water exchange with the Sea of Oman. In this regard, the hydrodynamic modeling by considering the effect of evaporation in the Oman Sea and the Persian Gulf has been done using the three-dimensional Mike3-Flow Model. The input hydrodynamic data is extracted from the HYCOM model and the required atmospheric data is extracted from the ECMWF model. To evaluate and validate the model, numerical results have been compared with TPXO data and tidal levels by means of statistical parameters. The results of this study show that the amount of cumulative water entering the Persian Gulf has a relatively linear relationship with the percentage of evaporation. Also, the increase in water evaporation from the surface of the Persian Gulf has a strong effect on the salinity of the Persian Gulf, and this effect is widespread but variable in the surface of the Persian Gulf, so that the areas closer to the Strait of Hormuz are less affected by the increase in evaporation, and the increase in salinity in the shallow northern as well as in the southern coasts have caused an increase in the average salinity of the Persian Gulf. On average, a 50% increase in evaporation increases the water salinity by 3 psu and a 100% increase in evaporation causes an increase in water salinity by 6 psu.

Air transportation has always been of interest to national managers and planners due to its positive features, including high speed, safety, and large capacity. However, various constraints affect the efficiency of this system. In this research, the resilience of the air transportation network is examined. Constraints are divided into two categories: natural events and sabotage events. In this study, data from domestic flights in Iran were used to analyze the resilience of the air transportation network. For this purpose, the number of serviced flights was considered as an indicator of network performance, and the cascade failure diagram method was used to analyze resilience. The results show that in the most pessimistic scenario, with the removal of three airports, network performance drops below 10%, as indicated by the cascade failure diagram. Additionally, the ideal scenario of network performance decline was examined, and the results show that in this scenario, with the removal of 90% of airports, network performance remains above 45%. Based on the conducted analysis, the biggest problem in Iran's air network is the excessive concentration of flights in a few specific and high-demand airports, which greatly affects network resilience in case of any issues occurring for them.

Rail transport is one of the important and vital infrastructures of any country. Building rail transport infrastructure requires a relatively high cost; But this cost is justified against its advantages, including high safety, cost-effectiveness, environmental friendliness and suitable for mass transportation. On the other hand, the use of the rail network, in addition to creating dependence on this mode of transportation, is also dependent on other infrastructures and its surrounding environment. These dependencies are more visible during the crisis and may, in addition to creating a crisis in the network itself, cause chain and cascade crises and increase the damages caused by the crisis. In this research, by examining different models of crisis management, laws and regulations and upstream documents and identifying the railway network of Yazd province and its dependencies, while finding the most important dependencies, we will present and propose a model of crisis management according to this infrastructure, and in this way, from the opinions of elites and Interviews and surveys have been used. The primary results of the research, which is the goal and basis of the design of the model, can be expressed as facilitating crisis management, maintaining the continuity of work and managing dependencies, and therefore, a suitable model has been proposed in three managerial, technical and human dimensions. Finally, the most important actions that should be taken in order to implement the model are given in the form of suggestions and implementation solutions.

Rail transport industry an handle a large amount of products, goods or passengers during a wide, scattered and diverse geography, which is accessible and penetrated by intruders and attackers and is also vulnerable to all kinds of physical and cyber attacks; move Therefore, it is not possible to strengthen and improve the level of security in this vast network against various types of attacks and intrusions, and it faces many obstacles and challenges. In this study, an attempt has been made to investigate the position and strategic importance of cross-border railways for the transportation of goods and passengers in the United States and investigate an unclassified set of seemingly simple attacks that have had destructive and complex effects on the traffic of the railway network and the health of citizens in the United States. be paid Also, the range of security measures of the rail transport industry and the American government, as well as the decision-makers and active activists in this field, were analyzed to reduce the risk factor and manage the crisis in complex, ambiguous and uncertain situations and when there are intrusions and structured attacks on the rail network of this country. take In this case study, the consequences of some successful attacks as well as the weaknesses and shortcomings of the American government system to ensure the security and safety of the rail transportation network in the implementation of programs and protective measures

Road networks are considered as the backbone of transportation systems that play an important role in the social and economic prosperity of societies. For this reason, it is very important to develop road networks with a higher resilience rate for normal operation during an earthquake. Earthquake damage to road networks cannot be accurately predicted because of various factors such as: age, condition of buildings, population density and unavailability of resources to reduce the risk. District 2 of District 16 of Tehran is actually the same neighborhood as Nazi Abad and is one of the oldest structures in Tehran, which is located in the south of the city. The main goal of this research is to compile the transportation strategies of district 2 of district 16 of Tehran by analyzing the documentary-field information and using the shapefile of the studied area in ArcGIS 10.3 software and with the help of SWOT technique and IE matrix. The prioritization of strategies has been done using the QSPM matrix. The findings and results of the research indicate that due to the concentration of commercial users and travel absorbers in the center of the district and the degree of wear and tear, the high fineness of the parts, the low permeability of the road network has increased the vulnerability of the road network in critical conditions.

In this research, soil stabilization has been done by an optimal combination of fibers and traditional stabilizers, as well as using the results obtained in the analysis of the stability of the roofs and finally simulating the results in the environment of genetic programming. A numerical model was obtained by simulating slopes in the OptumG2 software environment. Numerical simulation modeling environment was used by two famous artificial neural networks, the feed forward and genetic programming neural networks. For slopes with an angle of 75 degrees, the maximum vertical stress applied on the foundations is equal to 8, 285, 499, 808 and 1516 kilopascals for soils with a shear resistance of 25 kilopascals (or unstabilized soil), 100, 200, 300 and it was 400 kilopascals. It is worth mentioning that the relationship between the undrained bond strength and the slope reliability factor (for a constant condition of the slope geometry and the location of the foundation relative to the crest of the slope) is a linear relationship. Metal fibers showed the greatest effect on the strength of the fixed samples. Cement stabilizers showed more results than lime stabilizers. The increase in undrained soil resistance can greatly affect the stability of these slopes and also the maximum stress that can be applied to the crest of these slopes. In predicting the maximum amount of stress on the slopes, the artificial neural network analysis was a good representative of this issue.

The management of subway construction projects is very important due to the high cost and long duration and the economic, social and environmental impact. In order to properly and systematically monitor these projects, the critical factors of success in these projects must be identified, Prioritized and supervised them. For this purpose, in this research, the critical success factors in the projects are identified and categorized by reviewing the literature, then these factors are refined for metro construction projects with the fuzzy Delphi method. In the next step, the fuzzy DANP method is used to understand the interaction of the factors and obtain their weights. In the stage of identification of factors, 21 factors were identified and categorized in the four dimensions of finance, quality, sustainability, and organization, and 12 factors remained by performing two rounds of fuzzy Delphi. results show that The quality dimension affects the other three dimensions, which means the need to invest in quality to improve the performance of the project in all dimensions. Finally, the weights of the factors were obtained, which results shows the importance of the factors of ecological value and adaptation to weather conditions. These two factors are in the dimension of sustainability and it is important to pay attention to environmental issues in the success and sustainability of the project in the long term. The results of this research can be a guide for managers to effectively monitor subway construction projects to achieve success of various dimensions.

The purpose of this paper is to evaluate the effect of additives on the stabilization of divergent debris soils with poor geotechnical properties. This article gives special priority to our industrial materials such as fly ash and slag of steel furnace, and their effect is compared with conventional additives such as lime milk. Although the cost of lime milk is higher than live lime, it is preferred to live lime in agricultural fields for better efficiency and ease of use. The study of divergence in crops seems important because due to their increase and abundance in nature, they must be appropriately used with the help of measures. The loan source near the earthen dam, which contains divergent soils, can not be ignored and used in the clay core. In the past, clay soils were thought to have a high resistance to water erosion, but in recent years, the generalization of this issue has been limited. Because observations have been very confirming that in nature, there are clay soils that are highly vulnerable to erosion due to the existence of such soils in most parts of our country, measures such as stabilization of divergent soils or its improvement can be of great help to use these soils in engineering projects. This article will identify and study divergent soils and the phenomenon of divergence and evaluate the effect of additives on the stabilization of divergent soils.

Road safety has long been a major social concern for people and officials, and numerous treatments (or interventions) have been implemented to improve road safety. In general, road safety remedies can be policies, legislation and enforcement, physical changes to roads or networks, and other public-purpose measures that directly or indirectly affect traffic conditions, driving behaviors, and the travel environment. In recent years, researchers and decision makers have paid a lot of attention to drivers affecting the safety of transportation routes as a treatment, and in this research, the identification and prioritization of the drivers affecting the safety of transportation routes in the geographical area of Yazd province were investigated and analyzed. This research is practical from the point of view of the goal, and from the point of view of the control of the variables and the method of data collection, it is analytical-descriptive of the survey type. Data collection in this research is a combination of library and field methods, and a large amount of information was obtained using a questionnaire. The statistical community of this research is made up of experts and specialists. The data in this study were tested using the SWARA Cresolin, Zavadskas and Torxis method. The results show that according to the calculations in Swara's algorithm, among the main drivers, the vehicle criterion with a weight of 0.2462 is the first, the increase in road safety (roadside safety) with a weight of 0.2028 is in the second place, and the criterion of the role of supervising and governing institutions on the roads is in the third place with a weight of 0.2028. , the criterion of road geometric plan with a weight of 0.1813 is in the fourth place and finally the criterion of self-representation and expressiveness of the road is in the fifth place with a weight of 0.1674.

Overturn crashes are one of the most important road hazards. Due to the high severity and significant contribution of these types of accidents, it has created a set of preventive measures to reduce the consequences of these types of accidents. Therefore, the present study aims to provide a statistical model using two-dimensional logistic regression, in order to identify the variables that affect the probability of occurrence of overturned crashes in suburban roads. For this research, information from Form 114, traffic volumetric information and meteorological information in the years 92, 93 and 94 were used for Zanjan-Qazvin and Zanjan-Tabriz freeways. The results of this study showed that the probability model of free overturn crashes of Zanjan-Tabriz freeway was achieved by three independent variables of gender, driver's occupation and geometric status with an accuracy of 81%. While the probability occurrence model, the overturn crashes in Zanjan-Qazvin freeway were only achieved using two independent variables of driver occupation and load type with a percentage accuracy of 71%. Given to Zanjan-Tabriz model (the superior model), it can be concluded as a general result that overturned accidents are more dependent on human factors.

In recent years, the need for an accurate identification of the conditions of the earth has become apparent, in response to the growing need for larger and more deep underground spaces., underground excavations can be classified into three groups of tunnels, caverns and mines. The new township tunnels of the Pardis are part of the Phase 5, 8.9, and 11 new Pardis projects, which aim at providing access to these phases independently to the highway and the large Pardis of Tehran, and the arterial axis of the first phase of the 3.2 phase 1 and 4 new Pardis cities. The purpose of this research is to use different numerical methods for studying and analyzing the stability of Pardis tunnels in Karaj Formation using numerical methods of finite difference in continuous environment (FLAC software) and separate element in the discontinuous environment (UDEC software). In this research, the sustainability analysis of the tunnels of the Pardis was first performed and optimized by applying a variety of numerical methods. Finally, the results of different methods were compared with the results of the instrumentation. The results show that the model made by UDEC software is closer to real Earth conditions compared to the FLAC software. According to the results obtained from the comparison of the amount of displacement occurring around the drilled space, this environment has a discontinuous behavior.