Papers by Keyword: Bearing Capacity

Abstract: In order to manage urbanization in a responsible way, it is even more critical to perform either a prior geotechnical study or a geological study before the projects are started. However, performing these investigations usually brings about some extra expenditure which can raise the cost of the project by ten times the original budget. This case study is on the city of Casablanca, Morocco and aims at carrying out geotechnical and geological survey of soil and rocks using GIS and geostatical approaches. Its primary aim is to develop a systematic geotechnical database and relevant geotechnical maps which can be readily used by practitioners across civil and geotechnical engineering sectors without undertaking new geotechnical exploration. For this purpose, geological and geotechnical maps as well as data gathered from 100 region surveys were collected and processed. It has been demonstrated that the substratum of the located area in Casablanca, contains the deposits of silt, calcarenites, marls, graywackes, and siltstones. The oldest deposits date to the Middle Cambrian while the youngest to the Holocene. Two important maps one of material bearing capacity and other of substratum for accurate depiction on geotechnical data was prepared by integrating geostatistical concepts into GIS. The soil bearing capacity at the study site was found to range between 2 bars to 4 bars with moderate bearing grade structure in the area.

Abstract: The depth of the induced stresses of a rigid foundation known as significant depth, is related to the width of the foundation. The conventional bearing capacity equations can lead to significant inaccuracies if the top layer thickness is less than the significant depth of the foundation. In this study, series of 3D numerical simulation analysis on various sizes of foundation are performed. Two different soil profiles with same top layer underlain by, a) harder soil layers (Soil Profile A) and, b) weaker soil layers (Soil Profile B), were used in this study. The settlement profile showed that the settlement occurred to greater depth in soil profile B. The bearing capacity decreased significantly with increased foundation size. The bearing capacity was decreased by 85% from 108 to 16 kN/m², and by 93% from 97 to 7 kN/m² for foundation size of 2m×2m and 20m×20m in soil profile A, and B, respectively. The soil layers effect was more significant for large foundation size where the bearing capacity was decreased by 10 and 57 % in soil profile B for 2m×2m and 20m×20m foundation sizes respectively. The study emphasizes the need of incorporating the soil proper up to depth equal two times the foundation size.

Abstract: The results of experimental studies and computer modeling of reinforced concrete and fiber concrete cross-beam systems are presented. The authors have made a special stand, the design of which allows to carry out researches of bearing capacity and deformability of such systems under the concentrated and distributed static loads. Samples made of reinforced concrete and steel fiber concrete and consisting of four mutually perpendicular beams of rectangular cross-section were tested. The specimens were reinforced in the lower zone with longitudinal reinforcement of 8 mm in diameter, two rods in each beam. Steel-fiber concrete specimens have an additional dispersed reinforcement of steel fiber with bent ends in an amount of 1% by volume of concrete. A procedure of finite-element modeling and calculation of cross-beam systems in the licensed program ANSYS 17.1 was developed, and a comparison of the results obtained experimentally and on the basis of computer modeling was performed. The tests showed that dispersed reinforcement of the cross-beam system with steel fiber leads to an increase in its bearing capacity by 1.23 times. During modeling and finite-element analysis in the ANSYS 17.1 program, the increase in bearing capacity was 1.18 times. At the same time, the load-carrying capacity of the reinforced concrete cross-beam system obtained by the finite-element method was 13% lower than in the experiment, and that of the fiber-reinforced concrete system was 15% lower. At the same time, the discrepancy in the approaches considering torsion and not taking it into account is about 5% for all the samples studied in the work.

Abstract: The methodology of experimental research of long cylindrical shells to determine their stress-strain state, carrying capacity and crack resistance is proposed. To implement the task, the authors have developed a special stand. Eight cylindrical shell models were made for testing - four of reinforced concrete and four of fiber concrete. Fibro-concrete specimens-shells had additional dispersed reinforcement by steel fiber with bent ends in an amount of 1% by volume of concrete. All specimens-shells had a constant length and cross-sectional radius, and varied the thickness of the shell and the size of the cross-sectional section of the board elements. The paper presents the results of tests of reinforced concrete cylindrical shell, which showed that the carrying capacity of the shell was 96.4 kN, and the first crack formed with a load of 42.9 kN, which is 44.5 % of the carrying capacity. Up to the moment of bearing capacity loss, 8 cracks with the same initial opening width of 0.05 mm and maximum final opening width of 0.8 mm had formed in the shell. Computer modeling of the shell and calculations with ANSYS 17.1 licensed software were performed. The bearing capacity determined in ANSYS was 93.0 kN, which is 3.6 % less than in the experiment. The test methodology and the developed stand are universal and will be used for further research.

Abstract: Based on the flow equation of the ferromagnetic liquid lubricant for the “thin layer”, the continuity equation and the Darcy equation describing the flow of a lubricant in a porous body, the paper presents an accurate self-similar solution of the V-shaped sliding support with a porous coating of the base ring surface taking into account the rheological properties of the lubricant with ferromagnetic properties when the working gap is partially filled at the laminar flow mode. Analytical dependencies were obtained for the field of velocities and pressures in lubricating and porous layers. Besides, the main working characteristics of the studied friction pair are determined: bearing capacity and friction force. The paper provides the assessment of the influence of parameters characterizing ferromagnetic rheological properties, length of the loaded region of the Hartmann number and parameter characterizing the presence of electromagnetic field on the bearing capacity and friction force.

Abstract: The churches of the Broumov region are renowned for their unique baroque architecture, their distinct shapes, and sizes. They are an integral part of the Czech cultural heritage. If you analyze the churches, it becomes evident that both the local geological conditions and the municipal economic situation have played an important role in their current condition. Moreover, the local construction industry has been significantly affected by historical events. In this article we would like to present the effects of those factors on the current state of selected churches, namely on the bearing capacity of their walls. Besides being very interesting, it also plays a key role in the maintenance and the potential reconstruction of the churches.

Abstract: In this paper, performance of gravelly silty sand soil reinforced with geogrid are present and analyzed to improve the carrying capacity. For this, the geogrid was elaborated with a renewable material like bamboo with the same dimensions of polymer geogrids biaxial. This type of soil can be used for the construction of the sub-base and base of a pavement. California Bearing Ratio (CBR) tests was carried out to obtain the bearing capacity of the silty sand soil with and without bamboo geogrid. In addition, laboratory tests were carried out to obtain the mechanical properties of the bamboo. When comparing CBR results, an improvement in the bearing capacity was evidenced with the use of bamboo geogrid with a 20% increase in the carrying capacity. Finally, maximum tensile and bending strength of bamboo were 2000 kgf/cm² and approximately 0.018 kgf/cm, respectively.

Abstract: The paper presents the results of the study of the stress-strain state of polygonal shells of positive and negative curvature with different geometric shape of the plan, taking into account the influence of the prehistory of a high loading level. To derive the resolving equation, equation, a mixed-type equation of the moment theory of shells was used. The calculation of the investigated out according to the moment theory, taking into account the influence of a complex stress state edge effect. The numerical implementation of this solution is carried out in relation to hinged and restrained shells. The bearing capacity of short-term and long-term loaded reinforced concrete polygonal shells was investigated by the method of limiting equilibrium.

Abstract: Broumov Region and its group of churches represent a perfect example of symbiosis between Baroque architecture and countryside landscape. This peculiar heritage site requires specialized analysis to preserve its uniqueness. St. Barbara Church in Otovice, the one investigated in this thesis, was built by Christoph and Kilian Dientzenhofer. Nowadays, concerns about its stability and degradation process led to the necessity to investigate more deeply its current condition. Therefore, the main objective of the article consists in the FEM modeling and the evaluation of the bearing capacity of enclosure walls, with particular attention on the influence of the soil deterioration. In conclusion, technical advices are recommended.

Abstract: Two models of hollow core slabs were tested: reinforced concrete and steel fiber concrete. When designing slab models, the proportions of full-sized structures were preserved for the further possibility of correct data comparison. As a result of testing models of hollow core slabs, it was found that the bearing capacity of a slab with combined reinforcement is 24% higher than that of reinforced concrete, the deflection is 36% less, and the crack resistance is 18% higher. The use of steel fiber made it possible to avoid the brittle fracture of a steel fiber reinforced concrete slab, which was observed in the model of a conventional reinforced concrete slab.