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Abstract

Most of the railway lines in Slovakia were built in the second half of the 19th century, or until 1918 (the establishment of Czechoslovakia). Except for the post-World War II period, when approximately 71 % of the Slovak lines had to be renewed, limited funds have been spent on repair and reconstruction works on the lines located in the Slovak territory. As some trans-European corridors cross the Slovak territory and the Slovak Republic assumed obligations arising from the AGC and AGTC agreements, the line modernization is more than desirable. The primary objective of the modernisation of railway lines in the territory of Slovakia is to ensure a high-quality and safe railway, which by its qualitative parameters corresponds to the standards of developed European countries. In this context, the paper deals with a section of the modernised corridor no. Va, specifically the section Považská Teplá - Žilina. During the period 2014-2017, quality diagnostics of the performed work was carried out on the sub-ballast layers of the above-mentioned line. Consequently, we carried out an analysis of the obtained values of the deformation resistance of the subgrade surface, as the weakest element in the construction of the sub-ballast layers.

Abstract

This paper depends on a test examination on basalt fibres which started from volcanic shakes and were dissolved at high temperatures. These stones were accessible from the world’s profound hull. M30 evaluation of concrete was structured according to is 10262:2009 with basalt fibres. The fibres alongside mineral admixtures were utilized in three distinct extents, that is 0 %, 1 %, 2 %, 3 % by heaviness of cement. The goal was to decide the characteristics of fibre reinforced concrete with various fibre extents. The strength properties, for example, compressive strength, split tensile strength, flexural strength, shear strength and the impact on strength of concrete when it was unprotected to sulphate attack after stipulated extended ages of curing were contemplated and thought about. From the examination, it was discovered that the basalt fibre expanded the strength of concrete notwithstanding when unprotected to sulphate attack bit by bit when compared with consistent concrete. The ideal strength of concrete was accomplished with an enlargement of 2 % basalt fibre.

Abstract

Considering that the unevenness of the road surface is the primary source of the kinematic excitation of the vehicle, it is necessary to map the unevenness, and then to describe it mathematically. The data sets thus obtained represent an important input for numerical simulations of the motion of vehicles on the road. This paper deals with the analysis and comparison of results from two methods of mapping the surface of the road - exact levelling and spatial scanning. The obtained results are evaluated qualitatively and quantitatively by methods of mathematical statistics and probability theory.

Abstract

This article is a dimensioning study of the landfill locker dike of the city of Casablanca, where the geotechnical parameters of waste have particular limitations, theses limitation are a common characteristic for most developing countries. Considering the very small available land area in general, the objective is to achieve an optimal dimensioning of the locker to maximize the volume to be buried, while respecting the requirements of stability of the structure; namely, the model whose safety factor will be greater than 1.5. The Factor Of Safety (FoS) was calculated by the Finite Element Method (FEM) using “PLAXIS 2D” software. The results show that, for both cases (with and without final cover), FoS, as obtained from both the analysis, show a similar pattern, with the maximum FoS for low inclinations, especially those lower than 15.95°. The critical FoS (< 1), was obtained for slopes strictly greater than 21.80°. The study also demonstrated that the 3.5H 1V model could be considered as the optimal one that satisfies the structural stability requirements (FoS> 1.5) and maximizes the volume to be buried. Nevertheless, the validation of this model is conditioned by a geometric modification (weakening the lateral slope of the landfill, by moving the dikes by 3 m) and the improvement of the mechanical characteristics of the soil of the peripheral dike, through replacing the material with the compacted clay. This model was validated by PLAXIS, which showed that the FoS for the phase preceding the anchoring of the final cover is 1.577, which reaches 1.604 after anchoring.

Abstract

The paper deals with the determination of mechanical properties of fiber reinforced concrete in dependence on various dosages and recipe of concrete. The mechanical properties were determined for the default recipe of concrete, where the individual variants differ in the amount of fibers. The fibers dosing was 0, 25, 50 and 75 kg/m3. At the highest dosage of 75 kg/m3, the recipe is optimized with regard to the microstructure of the concrete. In the experimental program were determined compressive strength, modulus of elasticity, split tensile strength, flexural tensile strength and load-displacement diagram. The flexural tensile strength was determined based on a three-point and four-point bending test. Based on the evaluated data, the uniaxial tensile strength and the functional dependence for the resultant recipe of concrete with a dosage of 75 kg/m3 is with respect of the increasing importance and application of numerical modelling of building structures, the analysis is performed using non-linear calculation. The aim was to simulate the performed laboratory test and appropriately approximate the specific input parameters of the fiber reinforced concrete for nonlinear analysis.

Abstract

Degradation and disintegration of concrete depend on the formation of cracks and micro cracks intensively. With increase loading, micro cracks are linked together and form cracks. To solve the problem and to provide the homogenous condition, a series of thin fibers having been spread through the volume of concrete are used in the several last decades and they are called as fibers. In the study, the steel fibers integrated in the different percentages of weight have been investigated. The performance of fibers has been studied how to increase compressive strength, tensile strength, and bending strength. To survey compressive strength, tensile strength, and bending strength in the produced concrete, three plans of mixtures including the different percentages of the steel fibers have been examined. The results show that compressive strength in the concrete reinforced with steel fibers relies mainly on the quality of mortar. The added steel fibers cause the inconsiderable changes in the compressive strength of concrete. The results demonstrate that the concrete reinforced with steel fibers increase tensile strength considerably. The more the volume of steel fibers is, the more tensile strength is. Pozzolanic materials used in the specimens reinforced in steel fibers improve tensile strength. To investigate bending strength of the specimens reinforced with steel fibers, the study has used 4-point loading system. Generally, steel fibers used in the concrete increase bending strength of the concrete. The results indicate the increased steel fibers enhance bending strength in three plans of mixtures. Among the specimen reinforced with steel fibres, the most mechanical properties are related to the plans including 1, 1.5, and 2 percentages of dramix hooked steel fibers in the study. To examine crack pattern of the matrix tensile specimen reinforced with the different percentages of fibers, parameters such as the number of cracks, width of cracks, and distance between them are investigated.

Abstract

The paper presents the influence of Key Performance Indicators (KPI) on decision making during the architectural design process. In the beginning, the researcher selected a functional complex of industrial nature for the test and defined five criteria for evaluating the architectural design and then created two categories of result and process indicators to explore the decision making during the design process through Verbal Protocol Analysis (VPA). Two groups of subjects attended the VPA, while one group received the indicators; the other one did not receive the indicators. The protocols were transcribed and encoded to make the comparison more efficient. At the same time, the jury evaluated the sketches separately to check the previous results. The study indicates that the indicators were affecting the decision making and design process and design product simultaneously. First of all, framing decisions were made more organized and mature and at the same time increased in numbers, the key decisions were evaluated easier and in some cases divided into smaller decisions related to one or more criteria and then merged into a final concept, the enabler decision making was done more efficiently and faster because of better thought key decisions and the use of indicators for control. The design process, although still has iterative nature. However, iteration was done in smaller cycles due to the use of result indicators for evaluation and process indicators to lead the process. Indicators facilitate idea generation, and the whole process is without difficulties. The design quality assessment by the jury shows the improvement in the final quality of design outcome in specific aspects related to indicators.

Abstract

Concrete has today requesting execution prerequisites. The concrete strength emergency which started to pull in open consideration constrained the specialists to investigate the strength of concrete. Legitimate mix design and cautious development utilizing the best accessible materials and developments are significant to finish quality concrete structures. In the utmost current decade, the usage of Additional Cementing Materials (ACMs) has become a vital piece of high quality and superior concrete mix design. One of the significant changes is the presentation of small-scale innovation for concrete with fine and ultrafine cementitious materials. It is currently believable to achieve astounding molecule pressing and subsequently conform to the exhibition requests both in new and in the solidified states. In the prevailing examination the ACMs utilized are Fly ash, silica fume, Ground Granulated Blast Furnace Slag and Metakaolin which are prescribed by IS 456:2000 to recover the strength and durability of concrete. This paper shows the presentation of M30 to M90 grade of concrete with superplasticizer utilizing Rapid Chloride Permeability Test. Suitable mix of these ACMs can be utilized practically to advancement the chloride opposition of standard to high strength concrete mixes.

Abstract

The purpose of this paper is to justify that it is necessary to take account of physical and mechanical properties of soil and different materials of erected structure for damping vibrations in dynamic loads; to suggest tools for modelling the damping effect (natural or engineering induced) between foundation and soil. Certain technique is suggested for modelling behaviour of structure in time history analysis with account of material damping. In the software, the damping effect is modelled in two variants: Rayleigh damping (for structure) and finite element of viscous damping. When solving this problem, the following results were obtained: physical meaning of material damping is described; Rayleigh damping coefficients were computed through modal damping coefficients. Numerical analysis is carried out for the structure together with soil in earthquake load using developed FE of viscous damping. Time history analysis was carried out for the problem. Peak values of displacement, speed and acceleration at the floor levels were compared. Analysis results are compared (with and without account of material damping). Significant influence of damping on the stress-strain state of the structure is confirmed. Scientific novelty of the paper is in the following: the damping effect is proved to happen regardless of the presence of installed structural damping equipment; technique for account of damping with Rayleigh damping coefficients is developed; new damping element is developed – FE of viscous damping (FE 62), its behaviour is described as linear mathematical model. Practical implications of the paper: developed technique and new FE enables the user to carry out numerical analysis properly and work out a set of measures on seismic safety for buildings and structures.

Abstract

This research estimates the extent of using teleworking to mean the feasibility and appropriateness of this method of work for employees and professors according to their characteristics and features of career. The study population included university staff and professors in Tehran, and data collection was carried out through 447 questionnaires. A logistic regression model was used to investigate the transport demand caused by teleworking. The results showed that various factors, including history and percentage of telework, and after that, the time delay of home-to-work and travel distance, affected the model of transportation demand of professor’s members. For the staffing community, it had the most significant impact on teleworking, history and percentage of telework, followed by travel distances, latency from work to home, and latency from home to work.