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considering the benefits of "sense of place for the individual and society, the growth of the aging process in Iran, the importance of their presence in urban spaces as social equity and the impact of the environment on the level of performance and their sense of place, it is important to consider  environmental preferences of this population group. The aim of this research is to improve the relationship between the place and elderly and identifying the effective factors on the formation of sense of place in them. This study is in the context of qualitative methodology and content analysis. The data has been collected using a semi-structured in-depth interview technique and the sample size was determined by the theoretical saturation of the participants.
The research case is Tehran Railway Square; This square is one of the key gates of the Iranian capital. The collected data is encoded in 19 identifiers, 5 concepts and 3 categories. Categories including communicating with people, space efficiency, and space identity. Major concepts include the space-user community, space management, space facilities, space coherence, and space history. The results of this study also indicated that the view of the elderly is not limited to the form of the space, the space-users also affect their sense of place. Thus, the proposed model of this research can be a guide for urban designers and planners to have a positive effect on the sense of place of this population group according to the extracted identities.

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Ballasted track are of the most common species of railway in our country. The aim of this paper is study of three-dimensional models suitable for railway ballasted track and Dynamic analysis of those using numerical method Runge-Kutta 4th Order Method, after the dynamic analysis is performed and finally responses related to railway components be determined. To analyze the effect of passing under the railway train, a function of loading time on the railway line is applied and the effect of dynamic response under loading is evaluated. Previous researchers in the field activities of the railway system modeling and analysis of the dynamics on the two-dimensional models have been done. But this article is trying to consider the transverse nodes, on previous models and comes in three-dimensional dynamic analysis of the numerical method to be done. In other words, a new perspective in this article, consider nodes for transverse railroad modeling and numerical analysis of it. Brief description of the numerical methods mentioned along with the solving algorithm is mentioned in this article. In this research, simulation and modeling for rails, tie, connections and railway superstructure layers, is considered as elements of lump mass, spring and damper is used. Traditional methods used for the design of rail lines, based on static loading and quasi-dynamic analysis, the line components are analyzed, but in this article, according to the theories discussed in relation to rail component vibration, and study of dynamic load effects on track components into the issue to be more realistic. Responses obtained from dynamic analysis can be as input and issues designed to optimize rail components.

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To prevent unpleasant incidents, preservation high-speed railway vehicle stability has vital importance. For this purpose, the Railway vehicle dynamic is modeled using a 38-DOF includes the longitudinal, lateral and vertical displacements, roll, pitch and yaw angles. A heuristic nonlinear creep model and the elastic rail are used for simulation of the wheel and rail contact. To solve coupled and nonlinear differential equations, Matlab software and Runge Kutta methods are used. In order to study stability, bifurcation analyses are performed. In bifurcation analysis, speed is considered as the bifurcation parameter. These analyses are carried out for different wheel conicity and radius of the curved track. It is revealed that critical hunting speed decreases by increasing the wheel conicity or decreasing the radius of the curved track. Keywords: railway vehicle dynamics, nonlinear creep model, critical hunting speed, numerical simulation, bifurcation analysis Keywords: railway vehicle dynamics, nonlinear creep model, critical hunting speed, numerical simulation, bifurcation analysis

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In order to avoid unpleasant incidents, it is crucial to maintain the stability for a high-speed railway vehicle. In this research, a high-speed railway vehicle dynamics with 38 degrees of freedom was investigated, adding longitudinal movement equations. Another innovation of this investigation is to determine the critical velocity for the studied railway vehicle and using nonlinear elastic rail for the wheel and rail contact. In this study, the stable and hunting behavior of the system was investigated. To identify the chaotic motion of the system, frequency analysis has been performed. Also, by plotting the Poincaré map, dynamic behavior of the system is illustrated in a discrete state space, which could be a good criteria for the chaotic or periodic behavior of the system. Long-term behavior reveals that at Speeds lower than the critical speed, the system oscillates until it reaches the steady-state of the system. In steady motion, the oscillation continues until the critical speed When the system reaches the critical velocity, the motion on the limit cycle occurs for the first time and when the speed is higher than critical speed, the vibration amplitude increased smoothly. It was observed from the frequency response plot that the hunting frequency evaluated via the linear elastic rail is higher than that of derived using a nonlinear model.

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The Study on the Accelerometers of the past earthquake indicates that the vertical acceleration can reach values comparable to (and sometimes even higher than) the horizontal accelerations. This study investigates the effect of vertical component of earthquakes on the railway bridges with box girders cross section. Results of bridge analyses when vertical motions of earthquake are included in earthquake effects are compared to the case when vertical motions are excluded. Comparison of the results show that the vertical components of ground motions cause significant amplification in the axial force demand in the columns and moment demands in the box girder at both the midspan and at the face of the joints to column. Another finding from the linear analytical study is the fact that the effect of vertical component is completely uncoupled to the horizontal effects. With the results obtained, the comparison of the results with SDC-2006 suggestions shows that a unit multiplier of the dead load effect for compensation of vertical effect of earthquake. Finally, for considering the effect of an earthquake's vertical component, Dead Load Multipliers have been suggested; they are used in designing bridges.

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Electrification is one of the appropriate solutions to increase the railway network capacity. However, use of this solution without provision of the sufficient capacity and required infrastructure through the whole of the network, may not acceptably increase the attracted railway demand. In such cases, the electrification project may be uneconomical. This research aims to propose an algorithm to identify which bottlenecks of the network must be removed, in order to justify the electrification of a specific railway corridor. We investigated the electrification of the railway corridor at north of Iran. This corridor has a substantial capability for absorption of the freight transportation demand. The railway freight demand related to all of the origin-destination pairs of Iranian railway network, along with the capacities of all block sections of the network are considered as inputs of the problem. for freight assignment in the railway network, FARS (Freight Assignment in Railway System) software was used. This Iranian software is developed by transportation research center of Isfahan University of Technology (IUT), in 2013. The assignment method used in this software is based on Incremental assignment. Different scenarios are considered and two main criteria are employed to compare the scenarios: tonnage of increase in railway freight demand, and economic index of benefit to cost called Net Present Value. According to the results, the electrification of the railway corridor at north of Iran, with no resolution of the bottlenecks in other locations of the network, cannot absorb a remarkable demand. The individual electrification of the mentioned corridor can only increase the absorbed freight demand from 1.65 million tons to 1.95 million tons, which is not considered an impressive progress. In this scenario, the Net Present Value (NPV) index and Net Uniform Annual (NUA) index are negative, which implies that the execution of this scenario is uneconomical. The low increase of the demand absorption is due to the existence of the capacity bottlenecks in other parts of the railway network. The existence of these bottlenecks prevents the complete usage of the added capacity potential emerged from the electrification. Consequently, the possibility of handling the transportation demand at north of Iran would be limited. By using the algorithm proposed in the present study, the main bottlenecks which prevent the load flow through the network, were identified. Then, by execution of the capacity increase scenarios for the identified bottlenecks, the absorption of the railway freight demand was increased to 3.97 million tons, with positive values for both NPV and NUA indices, which imply the economic justification of the railway electrification at north of Iran, simultaneously with improvements for capacity bottlenecks at other parts of the railway network. In other words, to achieve the absorption of the freight demand of the railway corridor in north part of Iran, it is not adequate to merely increase the capacity of this corridor itself. The railway electrification project in a specified part of the network is preferred to be performed simultaneously by the capacity improvement projects in other parts of the network. The proposed algorithm can be used in decision making for justifying the railway electrification projects.

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Nowday, slab track is widely used in the world as railway supresturture because its advantages in comprison with conventioanl ballasted railway superstureure. So, design and analysis process of railway slab track is one the main issues in recent researches.  One of the main factor in the design and analysis of slab track is distrubtion of vertical load on longitudinal direction of the track (load distribution factor). In this paper, a 2D numerical model is developed in FORTRAN to investigate the effect of slab track properties on the load distribution factor. In this model, the slab track is comprised of rail, fastening system, concrete slab, elastic layer, concrete base and subgrade. Rail, concrete slab and concrete base are modeled as two nodeded beam element and fastening system, elastic layer and subgrade are simulated as spring element. According to the elements stiffness matrices, slab track stiffness matrix is developed. A wheel load is applied on the rail (in the middle of the model). Based on the two noded beam element shape functions, load vector of the model is developed. The equlibrium equation of the model is solved and load distribution factor is derived. To investigate the validity of the results obtained from the model, a comparsion is made between results obtained from the model and those of ABAQUS as a commercial finite element software. Rail displacement, concrete slab displacement, concrete base displacement and load disribution factor obtained from the ABAQUS are compared with those of the model developed in this paper and a very good agreement was illustrated between results. A parametric study was performed to investigate the effects of rail flexural rigidity, fastening system stiffness, concrete slab flexural rigidity, elastic layer stiffness, concrete base flexural rigidity and subgrade stiffness on the load distribtion factor. The results obtaine from the parametric study indicate that as the slab track element stiffness or flexural rigidity is decreased, the load distribution factor is decreased and vertical load is distributed widely in the longitudinal direction of the track. Rail pad stiffness has the maximum effect on the load distribution factor reletive to the other parameters. As the rail pad stiffness is changed from lowest to highest magnitude, the load distribution factor is varied from 0.3 to 0.7. The results obtained in this research indicate that propeties of lower slab track elements have lower effects on the load distribution factor compared to the upper slab track elements. So when the flexural rigidity of the concrete slab is changed from low to high, load distribution factor is changed from 0.52 to 0.54. Moreover, when the elastic layer stiffness, concrete base flexural rigidity and subgrade stiffness are changed from low to high, the load distibution factor are almost unchanged and is roughly 0.54. This shows that elastic layer stiffness, concrete base flexural rigidity and subgrade stiffness do not have any significant effects on the load distribution factor. So when a model is developed to calculate the load distribution factor and dcrease of analysis computation cost, elastic layer stiffness, concrete base flexural rigidity and subgrade stiffness could be ignored in the model. 
 

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In the present study, the results of two numerical finite element models prepared for the dynamic behavior of a concrete bridge in the rail transport network have been modified using the GP algorithm compared to the field data. In this research, taking into account the logical error for the data obtained from the two numerical models and field survey, in addition to modifying the results of models in the field of frequency, acceleration and displacement, the assumed values in the analyses in the error range should be corrected. The results of the GP algorithm showed the success of the algorithm in reducing errors between numerical and field results; so that the errors are limited in the range of %. The bridge studied in this paper is the Arroyo Bracea Bridge in Spain that is made of concrete beams and slabs. This is a bridge with two 15.25 m spans and a 45-degree angle with I-shaped beams crossing two railways. This bridge is modeled with two finite element methods and then is measured via a field survey to evaluate the results of the both models. Then, the difference between the results of the two numerical models and field survey is reduced by proposing the GP algorithm. This bridge is modeled by SAP2000 using orthotropic plate, isotropic plate and beams model. In both models, 6 degrees of freedom are considered for each point, and the interaction between the train and the bridge is neglected. The values of mass, modulus of elasticity, cross-sectional specifications, and degree of stiffness of the support are determined for each model. Accuracy of dynamic parameters was obtained from the studied bridge and experimental samplings are conducted from two finite element models. In addition to surveying the dynamic specifications of the soil around the bridge, in this study, the natural frequency of the bridge is obtained with analysis of modals and values of acceleration and displacement in traffic load conditions by installing the piezoelectric accelerometers at 11 points of the bridge. In this study, the soil characteristics around the bridge were also examined. First, by explaining the basics of the GP algorithm, the algorithm prepared in this article was introduced. The data on cross-sectional values, modulus of elasticity, and mass were selected as effective parameters from the initial data of the models and were randomly recorded along with field data in the error range of 1000. For having data with the same level, the values of parameters were normally distributed. Then, by implementing the algorithm proposed for the initial data of each model, a mathematical equation was presented per field data. These equations, in addition to reducing the error of the results of the model, also modify the initial data by providing correction coefficients. The proposed algorithm reduces the error data by 20.31% for acceleration on the part of the bridge deck.  Given the importance of dynamic behavior of the bridges in high-speed or heavy-load lines, the high accuracy of the results of the analyses related to this behavior is very important. However, the use of GP algorithm for calibration in analysis of bridge dynamic behavior is very restricted and there is still a possibility of development and improvement. One of the achievements of this paper is that it can be used in similar issues by providing mathematical equations, modifying initial parameters with correction coefficients, and significant reduction in error values. For further research, it is also suggested to investigate the matching factor in specific vectors in the modal analysis via this method. Determining the optimal values of the proposed algorithm parameters using the other methods and sensitivity analysis of GP algorithm compared to the changes in parameters are among the other proper suggestions for subsequent research.

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