Methodology for statistical analysis of squat rail defects

This paper proposes a methodology for statistical analysis of data obtained by visual inspection of squat defects on the rail head. Rail inspection by visual observation, including measurement of the squat defect position and depth was performed in Pančevo Varoš railway station in 2017. The obtained data about the squat rail defect (defect type 227 according to the UIC 712) on the main tracks was analysed in this paper. The rail defect position was determined regarding the position of the nearest sleeper in the track. Statistical analysis of the occurrence of squat rail defect was conducted according to the performed visual inspection in the field. Statistical data processing was performed for tracks zones according to the vertical stiffness of rail support. Furthermore, the impact of traffic load, the type and the arrangement of sleepers on the appearance of the squat rail defect was considered

Methodology for statistical analysis of squat rail defects

This paper proposes a methodology for statistical analysis of data obtained by visual inspection of squat defects on the rail head. Rail inspection by visual observation, including measurement of the squat defect position and depth was performed in Pančevo Varoš railway station in 2017. The obtained data about the squat rail defect (defect type 227 according to the UIC 712) on the main tracks was analysed in this paper. The rail defect position was determined regarding the position of the nearest sleeper in the track. Statistical analysis of the occurrence of squat rail defect was conducted according to the performed visual inspection in the field. Statistical data processing was performed for tracks zones according to the vertical stiffness of rail support. Furthermore, the impact of traffic load, the type and the arrangement of sleepers on the appearance of the squat rail defect was considered

The influence of lithium carbonate on the heat release during the hydration of Portland cement at the temperature 40°C

This work represents the stage of the author's research aimed at identifying the solutions for increasing the energy efficiency of the production of precast concrete and reinforced concrete products and structures in plant conditions due to reducing the temperature of heat treatment, or due to the reduction of duration of this technological process. The work provides results of the research of the influence of the admixture of lithium carbonate (Li2CO3) on the dynamics of hydration process of the binding systems on a cement basis in the conditions of the increased temperature (40°C). The research was performed using the method of isothermal calorimetry on the two various samples of the cement binder, conducted in various countries. The Li2CO3 admixture is accepted in dosages from 0.5% to 2.5%. The graphical dependence of the heat flow of the exothermic reaction of hydration on the used lithium carbonate dosage in the first days of curing of the samples is established and presented

Upravljanje naponima u šinama na železničkim mostovima

This paper analyses the stresses in continuous welded rails on bridges including the aspect of fatigue of rail steel. Furthermore, it examines the possibility to avoid rail expansion joints, while simultaneously exploiting the permissible stress capacity of the rail profile 60E1. Accordingly, general application of permissible values of pressure and tensilestresses prescribed in the current European standards was critically analysed. Paper includes specific application aspects of the prescribed stress values for railway bridges in Serbia. General algorithm for reducing the stresses due to the vehicle/track/bridge interaction, which is presented in this paper, was developed by the authors. This algorithm includes all essential parameters of the bridge structure and railway superstructure, as well as the influence of climate conditions and railway route design.Ovaj rad analizira napone u kontiunualno zavarenim šinama na mostovima, uključujući aspekt zamora šinskog čelika. Pored toga, ispituje se mogućnost izostavljanja šinskih dilatacionih sprava, uz istovremeno iskorišćenje kapaciteta dozvoljenih napona za profil šine 60E1. U skladu sa tim, kritički je analizirana opšta primena dozvoljenih vrednosti napona pritiska i zatezanja koje su propisane u važećim evropskim standardima. Rad uključuje aspekte posebne primene propisanih vrednosti napona za železničke mostove u Srbiji. U radu je predstavljen opšti algoritam za smanjenje napona usled interakcije vozilo/kolosek/most, koji je razvijen od strane autora. Ovaj algoritam uključuje sve bitne parametre konstrukcije mosta i gornjeg stroja železničke pruge, kao i uticaj klimatskih uslova i projekta trase pruge

СУХИЕ СТРОИТЕЛЬНЫЕ СМЕСИ ДЛЯ УСТРОЙСТВА ЗАЩИТНЫХ КОНСТРУКЦИЙ ОТ НЕЙТРОНОВ С ЭНЕРГИЕЙ 14,8 МэВ

Предмет исследования: бетон для устройства защитных конструкций от нейтронов с энергией 14,8 МэВ. При возведении защитных конструкций от ионизирующих излучений в зданиях объектов использования атомной энергии особое внимание уделяется качеству производства работ и оценке соответствия возведенных конструкций требованиям проектной документации. Цель исследования: получение необходимых данных для верификации программ нейтронно-физического расчета защитных характеристик бетонов различного химического состава. Материалы и методы: для достижения целей проведены расчетно-экспериментальные исследования с использованием генератора нейтронов с энергией 14,8 МэВ, комплекса спектрометрического и дозиметрического оборудования и расчетного программного комплекса ANISN. Исследования проводились для двух составов бетонов. Результаты: выявлена удовлетворительная сходимость расчетных и экспериментальных данных. Выводы: полученные результаты расчетно-экспериментальных исследований позволят разработать простые полуэмпирические методики расчета, которые могут быть использованы при проектировании составов бетонов с требуемой защитной эффективностью от нейтронов с энергией 14,8 МэВ и при контроле стабильности химического состава сухих бетонных смесей при их производстве и применении

Validation of the hdm models forcrack initiation and development, rutting and roughness of the pavement

Worldwide practice recommends validation of the HDM models with some other software that can be used for comparison of the forecasting results. The program package MATLAB is used in this case, as it enables for modelling of all the HDM models. A statistic validation of the results of the forecasts concerning the condition of the pavements in HDM with the on-field measuring results was also performed. This paper shall present the results of the validation of the coefficients of calibration of the deterioration models in HDM 4 on the Macedonian highways

Quality assessment of urban areas based on neural network modeling and GIS

In this article the authors carry out the research of the urban development areas structure and propose the system of its characteristics on the basis of sector affiliation of the municipal economy. The authors have developed an algorithm for quality assessment of urban development areas. The results of the research are presented on the example of several central quarters of Arkhangelsk city. The city’s residential development was formed in the periods from 1900-1950, 1950-1980 and from 2002 to date. It is currently presented by low-rise wooden, homestead type residential houses and barracks-type houses; mid-rise and high-rise brick and panel buildings of typical development, buildings of large-panel housing construction. Structural SOM-analysis compiled separate quarters of Arkhangelsk into 5 groups with a high level of characteristic similarity: "Commercial", "Prospective complex development", "Sustainable development", "Perspective renovation of residential development", "Investment-unattractive". Typical development strategies for each group of quarters are determined. Most developed areas characterized by upward height. The development strategies for depressed areas is in a high-rise building, which show the economic, social and environmental benefits of upward growth of the city. Using GIS allows to visually reflect the state and assess the quality of the urban development area by the aggregate of all parameters, and also to assess the quality of the quarters for each sector

Quality assessment of urban areas based on neural network modeling and GIS

In this article the authors carry out the research of the urban development areas structure and propose the system of its characteristics on the basis of sector affiliation of the municipal economy. The authors have developed an algorithm for quality assessment of urban development areas. The results of the research are presented on the example of several central quarters of Arkhangelsk city. The city’s residential development was formed in the periods from 1900-1950, 1950-1980 and from 2002 to date. It is currently presented by low-rise wooden, homestead type residential houses and barracks-type houses; mid-rise and high-rise brick and panel buildings of typical development, buildings of large-panel housing construction. Structural SOM-analysis compiled separate quarters of Arkhangelsk into 5 groups with a high level of characteristic similarity: "Commercial", "Prospective complex development", "Sustainable development", "Perspective renovation of residential development", "Investment-unattractive". Typical development strategies for each group of quarters are determined. Most developed areas characterized by upward height. The development strategies for depressed areas is in a high-rise building, which show the economic, social and environmental benefits of upward growth of the city. Using GIS allows to visually reflect the state and assess the quality of the urban development area by the aggregate of all parameters, and also to assess the quality of the quarters for each sector

Review on the Pavement-repairing Measures as a Condition for the Choice of Road-Maintenance Strategy

The road-maintenance strategies vary from one country to another, and even between the road management authorities within a one single country. It is not surprising, as there is not best maintenance method, nor a universal set of strategies that can be applied equally everywhere. Generally, there are strategies acceptable in certain conditions, but the factors influencing the selection process are diverse and very complex. This paper will present a review of the various measures that can be applied on the roads, which is certainly the basic condition of selection of an appropriate maintenance strategy

Review on the Pavement-repairing Measures as a Condition for the Choice of Road-Maintenance Strategy

The road-maintenance strategies vary from one country to another, and even between the road management authorities within a one single country. It is not surprising, as there is not best maintenance method, nor a universal set of strategies that can be applied equally everywhere. Generally, there are strategies acceptable in certain conditions, but the factors influencing the selection process are diverse and very complex. This paper will present a review of the various measures that can be applied on the roads, which is certainly the basic condition of selection of an appropriate maintenance strategy