scholarly journals Research of stress-deformed state of the rammed monolithic reinforced concrete cone-shaped piles with side and bottom forms from crushed stones

Author(s):  
Elvira R. Kuzhakhmetova

Relevance. In the construction of buildings and structures, driven piles with a square cross section are most widely used. To install them in the working position, the percussion method is used. However, in cramped conditions, shock loads can lead to dangerous conditions and destruction of structures of nearby buildings. In such a situation, it is necessary to use rammed piles, since technological solutions for their construction are not associated with shock effects on the soil. One such solution is the new rammed cone-shaped pile design, which is installed without excavation. The aim of the study is to analyze the influence of the geometric parameters of the pile on its bearing capacity under the action of external loads, in particular, the angle of its taper. Methods. The results of a numerical analysis of the stress-strain state of a pile operating in a soil massif were obtained by the finite element method. Results. In the computational study, a comparative analysis of the state of piles of different lengths and geometries under the action of external loads was carried out. The influence of the angle of inclination of the lateral surface of the pile on its bearing capacity is considered. Rationalization of the pile design was carried out taking into account the total costs of building materials. Variants of geometric and design solutions for piles with a length L from 1 to 10 m are proposed. In subsequent articles, it is proposed to consider the effect on the bearing capacity of the pile of the geometric parameters of the crushed stone shell and the lower crushed stone spherical expansion, as well as to carry out a comparative analysis of the numerical results with experimental data obtained in laboratory and field conditions.

Author(s):  
Svitlana Deryzemlia

The development of modern construction is closely related to the efficient use problemof building materials in terms of rational use materials’ strength properties. The search of rationalstructure in terms of geometric parameters, the materials use and providing the same bearingcapacity is important question in the modern building. The purpose of article is to carry out acomparative analysis of the geometric and strength characteristics of different reinforced concretecross-sections, and consideration of existing methods for calculating the bearing capacity andassessment of the stress-strain state of reinforced concrete beams.The steel-concrete structures using in different building structures is paid much attention in theworld practice. The steel-concrete structures widespread using leads to the economy of materials,reducing the complexity of manufacture, reducing time erection. The using of reinforced concreteleads to significant economy of steel, and set the new tasks for the engineers in the same time: ownweight and geometric parameters reducing of the cross-section without reducing of bearing capacityin whole. With the search for new structures that would meet the building requirements and usage ofdifferent building, nowadays significant attention pays to the improvement and development of thesteel-concrete elements. During the development and improvement of steel-concrete structures,significant changes have been made in terms of ensuring the joint operation of reinforced concreteand steel. Such structures require constant research and improvement in order to reduce their ownweight, financial costs, etc. The question of finding a rational structure in terms of geometricparameters, the materials using, as well as ensuring the same bearing capacity is currently important


2021 ◽  
Vol 2021 (24) ◽  
pp. 48-59
Author(s):  
Anatolii Mudrychenko ◽  
◽  
Ivan Balashov ◽  
Sergey Illyasch ◽  
◽  
...  

ntroduction. Rehabilitation of public roads network requires a comprehensive recovery with strengthening of the bearing capacity of the pavement foundation. Rehabilitation of the foundation bearing capacity performed by arranging layers of road material made by cold recycling technology (hereinafter — CRRM) in accordance with [4] or by arranging a layer of crushed stone — sand mixture reinforced with cement or complex binder (hereinafter — CSSM 20) according to [13]. Purpose. The purpose of the work is to study the feasibility of using acrylic additives for the preparation of mixtures made by cold recycling technology and crushed stone-sand mixtures treated with cement in the layers of pavement foundation. Materials and methods. Experimental comparative tests of CRRM and CSSM 20 with different content of complex binder were performed. Results. Feasibility of acrylic additives use has been established (hereinafter — the additive) for the preparation of CRRM and CSSM 20 in the pavement foundation layers. Recommendations on technological parameters of preparation, transportation, laying and compaction of mentioned mixtures are given. Conclusions. Performed researches have shown that according to physical and mechanical indicators CRRM and CSSM20 meet the requirements of the current normative documents of Ukraine. The advantages of use are noted.


Author(s):  
S.I. Karatushin ◽  
D.A. Khramova ◽  
N.A. Bildyuk

The paper introduces the results of studying the stress-strain state of the Novikov gearing in comparison with the involute gearing, similar in geometric parameters. In both versions, the wheel and gear are selected in size and gear ratio in accordance with the most common recommendations without additional hardening by chemical heat treatment. The zone of multiple contact of mated profiles is analyzed: changes in the geometry of contacts, pressure in the contact and stresses in various phases of gearing.


Author(s):  
Nahla Mohammed Salim ◽  
Shatha Hasan ◽  
Kawther Al-Soudany

Many researchers’ studies have shown that stone column is the best material to use to improve the bearing capacity of clayey soils. There are millions of waste volumes resulting from daily human activities. This excess waste leads to disposal problems and also causes environmental contamination and health risks. Demolished concrete is such one waste material that is produced from building demolition in Baghdad, Iraq. This paper describes experimental work conducted at the University of Technology that was carried out to investigate the improved bearing capacity of soft clay using crushed stone, followed by replacing crushed stone with concrete waste with the same relative density and grain size. The replacement was carried using waste concrete with different percentages corresponding to 25%, 50%, 75%, and 100%. The main conclusion drawn is that the bearing capacity increased to 119% by using crushed stone column, while the bearing capacity increased to 155% by using 100% of crushed concrete waste.


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