scholarly journals Influence of house bearing construction rigidi-ty of precast reinforced concrete on stress-strain state Continuous Flight Auger (CFA) piles foundations

2020 ◽  
pp. 48-57
Author(s):  
Viktor Nosenko ◽  
Oleg Krivenko
Keyword(s):  
Reinforced Concrete ◽  
Strain State ◽  
Residential Buildings ◽  
Precast Concrete ◽  
Relative Deformation ◽  
Construction Time ◽  
Stress Strain ◽  
Stress Strain State ◽  
Basement Floor ◽  
The Difference

At present, the tendency to build multi-storey residential buildings has become widespread in Ukraine. This is due to a number of reasons: significant increase in land prices in cities, dense urban development and the availability of appropriate equipment for the construction of such structures. One of the most common materials for multi-storey buildings is monolithic reinforced concrete. The main advantage of monolithic structures is the possibility of free spatial planning and the possibility of uniform redistribution of forces in the elements of the frame - the house works as one rigid entire structure. On the other hand, such structures require a long construction time and appropriate highly qualified control of monolithic works. Therefore, as an alternative, prefabricated reinforced concrete structures are used to accelerate the pace of construction. In this work, the influence of the rigidity of a precast reinforced concrete house on the stress-strain state of CFA piles foundation is investigated. The stress-strain state of a precast reinforced concrete building with two basement options is analyzed: precast and monolithic.                                                 The numerical modeling of the interaction of the system elements is used as a research method: soil base - foundation - aboveground structure. It was found that the replacement in a prefabricated house only one basement floor of precast concrete on a monolithic one affects the redistribution of forces, so the self-supporting wall is loaded 2.6 times, and the busiest wall, which rests on both sides of the floor slab, is unloaded to 2.1 times.  It was found that in the case of a basement made of precast reinforced concrete with a precast basement the difference efforts in pile heads (under the load-bearing walls) can differ 1.98 times, and in the case of a monolithic one 1.17 times. So it is mean, the monolithic foundation redistributed of efforts between the piles is more uniform. It is established that the monolithic reinforced concrete basement, in comparison with the prefabricated one, reduces the uneven settlement of the foundation by 2.4 times. When designing large-panel houses, it is advisable to provide a basement floor monolithic - this will allow to load the fundamental constructions more evenly, which in its reduction reduces the relative deformation of buildings and reduces their cost.

scholarly journals The Stress–Strain State of Three-Layer Precast Flexural Concrete Enclosure Structures with the Contact Interlayers

Buildings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 88
Author(s):  
Vu Dinh Tho ◽  
Elena Anatolyevna Korol ◽  
Nikolai Ivanovich Vatin ◽  
Hoang Minh Duc
Keyword(s):  
Reinforced Concrete ◽  
Strain State ◽  
Crack Formation ◽  
Concrete Beams ◽  
Precast Concrete ◽  
Concrete Structures ◽  
Reinforced Concrete Beams ◽  
Stress Strain ◽  
Stress Strain State ◽  
The Moment

The research object was three-layer reinforced precast concrete enclosure structures. The structures consist of heavy concrete B25 in the external layers and polystyrene concrete B1 in the internal layer. The stress–strain state of precast concrete structures during crack formation was studied by considering the influence of contact interlayers between different types of concretes. Stereoscopic microscopy and scanning electron microscopy were used in the experimental study of multilayer concrete blocks. Samples were made with a varied break time from 30 min to two hours between the previous and the next concrete layer placings. The experimental results showed that the contact interlayer with mutual penetration of aggregates into the adjacent concrete layers is formed in the successive layer-by-layer placing of various concretes. The thickness of the contact interlayer was up to 1 cm. The contact interlayer affects the solidity of the concrete layers’ connection and the structure’s stress–strain state. A model and method for calculating cracking in three-layer reinforced concrete structures with contact interlayers based on analytical and numerical calculations are proposed. Experimental data confirm the proposed calculation method. The results of three-layer reinforced concrete beams calculations show that: (i) the difference of the moment during crack formation in three-layer reinforced concrete beams schemes with and without taking into account the contact interlayer can reach 9.9%; (ii) the moment during crack formation obtained according to the proposed method is greater than that obtained according to the scheme of the cross-section conversion from 7.4% to 9.1%.

scholarly journals Investigation of hydrogeomechanical parameters of loess massifs in conditions of technogenic underflooding and development of technical recommendations for strengthening of bases of foundations

2019 ◽  
Vol 28 (1) ◽  
pp. 173-179 ◽  
Author(s):  
I. O. Sadovenko ◽  
A. M. Puhach ◽  
N. I. Dereviahina
Keyword(s):  
Strain State ◽  
Quantitative Estimation ◽  
Residential Buildings ◽  
Finite Element Approximation ◽  
Element Approximation ◽  
Soil Base ◽  
Stress Strain ◽  
Elastic Mode ◽  
Stress Strain State ◽  
Water Saturated

Based on the analysis of actual data and the results of numerical modeling, dependencies of deformations of the investigated residential complex due to technogenic moistening of a loess massif of soils are investigated. It was established that a dynamics of subsidence of bench marks in time is closely correlated with a moistening mode. In order to form a picture of dynamics of development of moistening phases of the massif and a quantitative estimation of main factors of their formation, a numerical model of the loess massif was built, based on the finite element approximation of the section of built-up area of the residential complex. Stability of a soil massif was estimated by the character of development of plastic deformation zones. Analysis of a stress-strain state of a rock massif indicated that water-saturated soils are partially in a state of plastic flow in a base. The development of shear deformations is most characteristic within a zone of the main moistening, as well as a boundary of its front. Development of rupture disturbances at the edge of the contour of buildings corresponds with the formation of tear cracks. An intensification of subsidence of buildings with simultaneous frontal and subvertical technogenic moistening of loess soils can be noted. Model estimations of a stress-strain state of the pile foundation, considering the uneven subsidence that occurred along the perimeter of residential buildings, show that the elastic mode of their deformation has not been exhausted. Options of redistribution of loads from residential sections onto an additional pile field, regulated base moistening and grouting of soils are considered as engineering measures to prevent further deformation of the residential complex. Stabilization of a soil base by means of high-pressure cementation is the most acceptable in the present conditions. Technological scheme of cementation of the soil base is recommended, as well as measures after the base stabilization, such as monitoring of further deformations of the complex itself and parking structures, and possibilities of constructing auxiliary drainage.

Investigation of the Stress-Strain State of a Steel Column Base Connection for Seismic Regions

2022 ◽  
Vol 906 ◽  
pp. 93-98
Author(s):  
Tigran Dadayan ◽  
Lusine Karapetyan
Keyword(s):  
Reinforced Concrete ◽  
Strain State ◽  
Main Type ◽  
Industrial Building ◽  
Stress Strain ◽  
Concrete Foundation ◽  
Stress Strain State ◽  
Steel Base ◽  
Steel Column ◽  
Seismic Regions

Currently, the main type of connection between a steel column and a reinforced concrete foundation is a steel base, which is often economically unprofitable due to its size, number or diameter of anchor bolts. Not only in Armenia, but also in most countries, a steel base is the main type of connection between a steel column and a reinforced concrete foundation. The usage of other types of connections is associated with both new calculation methods and technological problems. The possibility of computation and design of the connection of a steel column with a reinforced concrete foundation in seismically active regions using shear studs is considered in this work, a reinforced concrete section with longitudinal reinforcement is used for this type of connection which ensures a smooth transfer of forces from the column to the foundation. Based on the example of the connection of a single-story industrial building column shows the change in the stress-strain state of the connection under axial force and bending moments for seismic regions. Not only the feature and construction technology of the connection considered in the work, but also proposes a calculation method with future possibility of its subsequent inclusion in the building codes of the Republic of Armenia.

scholarly journals Mathematical model of the stress-strain state of a rod with an inhomogeneous layered structure

2021 ◽  
Vol 82 (4) ◽  
pp. 14-22
Author(s):  
S. M. Akhmetov ◽  
◽  
M. T. Userbayev ◽  
Zh. U. Iklasova ◽  
A. B. Bolatova ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Layered Structure ◽  
Strain State ◽  
Stress Strain ◽  
Stress Strain State ◽  
Current State ◽  
Tension And Compression ◽  
The Difference ◽  
State Of Research ◽  
Wooden Structures

The stress-strain state (SSS) of a rod with an inhomogeneous layered structure is considered. On the basis of a brief review and analysis of the current state of research of rod systems, the relevance of the study of the SSS of layered-heterogeneous wooden structures is substantiated, taking into account the presence of different resistance of layers to tension and compression. On this basis, the authors solve the problem of determining the SSS of layered-heterogeneous wooden rods in creep conditions, where factors such as humidity and temperature, as well as the difference in the resistance of wood layers to stretching and compression are taken into account. When solving the problem, the mechanical-sorption creep of wood is also taken into account.

scholarly journals Structural solution of the horizontal joint of floor slabs in girderless frame

2021 ◽  
Vol 274 ◽  
pp. 03017
Author(s):  
Juliya Mironova
Keyword(s):  
Strain State ◽  
Precast Concrete ◽  
Stress Strain ◽  
Stress Strain State ◽  
Floor Slabs ◽  
Speed Up ◽  
Shear Compliance ◽  
Horizontal Joint ◽  
Structural Solution

Despite the widespread use of monolithic construction, precast concrete remains in demand in the construction of residential and administrative buildings. Regardless of the advantages in technology and the quality of work, it is necessary and appropriate to modernize the existing design solutions, which allows you to simplify and speed up the technological operations during construction. Moreover, in the construction of complex nodes and joints, the qualification of workers is important, so simplifying the work without losing the quality of construction and ensuring strength, stability and durability is an important task. This problem can be solved by using modern embedded parts in the joints that do not require welding and other complex technological operations. In this paper, a constructive solution of the horizontal joint of the floor slabs located in the zone of action of minimal forces is proposed on the example of a girderless frame. The purpose of the study is to determine the stress-strain state of the proposed structural solution of the horizontal joint of floor slabs using loopshaped embedded parts «PFEIFER» and to develop recommendations for determining the shear compliance. Based on the analysis of the results of numerical modeling, the features of the stress-strain state of the joint during shear operation are revealed. The results obtained can be used in the design of buildings with precast-monolithic ringless frames, in the modernization of existing standard solutions of precast-monolithic frames, as well as other load-bearing systems made of precast concrete.

scholarly journals Consideration of the loading of the traffic lines in the design of automobile roads

2021 ◽  
Vol 274 ◽  
pp. 02009
Author(s):  
Denis Nikolenko ◽  
Maxim Nikolenko ◽  
Anastasiya Filippova
Keyword(s):  
Traffic Flow ◽  
Strain State ◽  
Dynamic Deformation ◽  
Uneven Distribution ◽  
Stress Strain ◽  
Stress Strain State ◽  
Freight Traffic ◽  
Design Solutions ◽  
The Difference ◽  
Strength And Durability

The article focuses on the importance of the strength and durability of highways due to the projected increase in freight traffic. It also describes the consequences of uneven distribution of loads in traffic lanes, depending on the prevailing traffic in each lane. The studies, that were carried out earlier by various scientists, were taken into account, thankfully to which results were obtained on the composition of the traffic flow, the difference in the loading of road pavements, as well as the stress-strain state of road structures. As a result, a model that reflects the dependence of the influence of the speed of movement of vehicles on the dynamic deformation of structures, was developed. Consequently, a number of design solutions were established to ensure the required strength of all structures.

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