1,720,964 research outputs found
TO RECORDING OF CRACKS AVAILABILITY IN EVALUATION OF STRESS-DEFORMED PAVEMENT CONDITION
No full textThe paper shows the methods for determination of border conditions in transferring for the limited sphere in the problem of stressed deformed condition of multilayer pavement with single vertical crack. With the purpose of the increase for the density of finite element grid in the close approximation to the top of a single crack the problem is solved for two stages. For the first stage the whole sphere has been considered, which consists of multilayer pavement on the ground foundation. The investigated sphere contains single vertical crack, located in the bottom part of the structural layer the third from the above. Then from the obtained solution the sphere of limited sizes has been cut imaginatively, which contains the crack, allowing application of smaller finite element breakdown in it, and the results of the first stage for the solution has been used as the border conditions for the limited sphere.
Meanwhile, the method of piecewise nonlinear interpolation has been used during interpolation of horizontal transferring for side boundaries due to their high gradients. For example, to interpolate the horizontal transferring of the right boundary for the limited sphere the interpolation sphere had to be divided into 5 segments, where the polynoms of the 1st, 2nd and 3rd orders have been used. To interpolate the transferring of left boundary of the limited sphere the similar polynoms, multiplied to (-1) will be used.
Quadratic eight-node solid elements have been used to investigate the flat deformed condition of pavement structure with the crack under the impact of single automobile wheel.
By means of the method for problem solving regarding the stressed-deformed condition of the multilayer pavement with the single vertical crack one can:
- study in details the regularities for the variation of stresses and deformations in the close approximation from the crack edge and crack tip;
- using the data regarding the stresses evaluate the strength characteristics of the pavement structure by the stress intensity coefficients and (or) J-integrals, which allows prediction for the possibility of further crack extension
ABOUT STRESSED DEFORMED CONDITION OF FLEXIBLE PAVEMENT WITH CRACK
No full textPaper shows the results for construction of mathematical model for multilayer pavement structure, in one layer of which the single vertical crack is initiated.
During problem solving for mechanics of solid deformed body, to which the problem of stressed deformed condition of multilayer pavement relates, one can use program complex ANSYS, which showed itself to good advantage in world practice, where finite element method is used. However, the availability of cracks of various length and spatial orientation makes the use of ANSYS not very efficient, as at variations of geometrical parameters for cracks, it is required to introduce changes into leading program, which is not very convenient to make in the program on ANSYS, as many operations have been performed secretly from the researcher.
Based on the above JSC “KazdorNII” has developed the calculation program BASIC_MKE in terms of MATLAB. As the singularity is available in crack points, calculations should be made with high accuracy, for that reason quadratic elements with eight nodes have been used in the developed program.
To imitate the availability of a single crack the imaginary void is introduced into calculation scheme with initial zero area, which allows considering of adhesion conditions between asphalt concrete layer with crack and underlying gravel layer. For approbation of the created calculation program, the formulated problem is solved in parallel in program complex ANSYS, and components of tensor deformation, obtained by two programs, are compared among themselves. Comparison of the results for problem solution according to program BASIC_MKE with the results of solution of the same problem according to program in ANSYS shows that the developed calculation program in terms of MATLAB is functionally operative
TO MODIFICATION OF ROAD CLIMATIC ZONING OF KAZAKHSTAN
No full textPaper shows short information regarding meteorological stations for weather observation in Kazakhstan. Data are represented regarding maximum and minimum values of air temperature for the period from 2006 to 2011, obtained by data processing of 40 meteorological stations of Kazakhstan. The results are represented in the form of climatic map of the Republic for minimum air temperature values for the specific period of time. Adjusted map is represented regarding soil frosting depth throughout Kazakhstan, constructed on the basis of frosting depth data, determined by calculation according to empiric formula, developed in JSC KazdorNII. Information is shown regarding automatic sets for temperature and moisture measurement in points of pavement and subgrade of highways, installed by JSC KazdorNII in five regions of Kazakhstan. Aiming at the performance of long-term monitoring for temperature and moisture variation in points of pavement and subgrade of highways 3 special measurement sets, equipped with sensors of temperature and moisture (on road sections of the highways with asphalt concrete and cement concrete pavements) in different climatic conditions were installed close to Astana city in 2010. Then similar sets were installed close to Oskemen, Almaty, Shymkent, Atyrau cities in 2013.
Information is contained regarding construction of climatic maps by other specialists. Empiric ratios have been used, which are based on meteorological data regarding air temperature variation, during mapping on frosting depths of subgrade of the highways. It is noted that together with the increase of stations number for experimental research of temperature and moisture variations in road structure in time, it is required to develop widely the works on investigation of processes for non-stationary temperature field variation and moisture regime in road structure by mathematical modeling methods
Analysis of pavement condition survey data for effective implementation of a network level pavement management program for Kazakhstan
Get PDFPavement roads and transportation systems are crucial assets for promoting political stability, as well as economic and sustainable growth in developing countries. However, pavement maintenance backlogs and the high capital costs of road rehabilitation require the use of pavement evaluation tools to assure the best value of the investment. This research presents a methodology for analyzing the collected pavement data for the implementation of a network level pavement management program in Kazakhstan. This methodology, which could also be suitable in other developing countries’ road networks, focuses on the survey data processing to determine cost-effective maintenance treatments for each road section. The proposed methodology aims to support a decision-making process for the application of a strategic level business planning analysis, by extracting information from the survey data
Analysis of natural stone block pavements in urban shared areas
No full textThis paper analysed and verified an existing block stone pavement in an urban shared area. Fatigue and rutting verification was performed respectively for bound and unbound pavement materials using analytical curves available in the literature. The commercial finite element (FE) software Abaqus® was used to calculate the response of the pavement when subjected to different loading, construction and geometrical configurations (i.e. type of analysis, shape and size of meshes, boundary conditions, and bonding contacts between the pavements layers). At the end of this study, a static model of a structure with hexahedral blocks having sides of 0.02 m, with full bonded layers and restrained horizontal displacements on the model sides, was implemented to evaluate the maximum tensile stress induced in a block when the load is applied at its centre. This analysis highlighted the need for rigorous criteria for a correct design, in order to avoid inappropriate and expensive use of road materials. Keywords: Block pavement, Commercial vehicle loads, Finite element model, Hexagonal Stone block, Pedestrian pavement, Shared are
Temperature and moisture distribution in a highway in south-eastern Kazakhstan
Get PDFThe matters of investigation for water thermal regime of pavement and subgrade structures of the highways are especially important as the moisture and temperature distribution in pavement and subgrade layers impact greatly on their deformation and strength indicators. Experimental results, which can be obtained by special measurement devices, are primary ones for establishing of peculiarities and regularities for distribution and migration of heat and moisture in the mentioned structural elements of the highways. Special measurement devices are required to obtain such experimental data. The paper shows the results for analysis of temperature and moisture variation in points of pavement and subgrade of “Almaty-Bishkek” highway. Temperature measurement has been performed by set of special sensors. Regular temperature and moisture measurement have been performed for the period from September 18, 2015 to June 2, 2016. Regularities for temperature regime variation in points of pavement for 24 hours are coordinated with air temperature variations. Amplitude of vibration for temperature is decreased with the depth increase. Moisture in subgrade points is gradually decreased with the reduction of daily average air temperature
MULTI-CRITERIA CHOICE OF THE REGION FOR THE CONSTRUCTION OF A LOGISTICS CENTER BASED ON AHP: CASE STUDY FOR KAZAKHSTAN
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Multi-criteria choice of the region for the construction of a logistics center based on AHP: case study for Kazakhstan
No full textThe current state of the regional market of transport and logistics services in Kazakhstan is characterized by a disparity between the increasing demand for Logistics services and the lack of logistics capacity. In this article, the authors propose a method for determining the most promising areas of the Republic of Kazakhstan for the construction of a logistics center, based on the Analytic Hierarchy Process (AHP)
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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