DEFORMATION CRITERIA FOR SPECIAL LIMIT STATE OF RC FRAME BAR ELEMENTS IN COMPRESSION

2020 ◽  
Vol 91 (5) ◽  
pp. 59-69
Author(s):  
S.Yu. SAVIN ◽  
Keyword(s):  
Reinforced Concrete ◽  
Strain State ◽  
Limit State ◽  
Normal Operation ◽  
Deformation Analysis ◽  
Concrete Element ◽  
Stress Strain ◽  
Limiting State ◽  
Emergency Situations ◽  
Stress Strain State

At emergency situations caused by the sudden removal of one of the load-bearing elements from the building frame, a stress-strain state is more disadvantageous in comparison with their stress-strain state at the stage of normal operation. In cases where the eccentrically compressed elements have an "elegant" section, or have acquired environmental (corrosion) or mechanical (chips) damages during operation, as a possible scenario for the exhaustion of their bearing capacity is buckling. The paper proposes an approach to the construction of deformation criteria for assessing the special limiting state of eccentrically compressed bar elements of reinforced concrete frames. The approach is based on the use of a combination of nonlinear deformation analysis and nonlinear form stability analysis. It is shown that the limiting values of deformations for the considered reinforced concrete element can be determined by the criteria of strength or stability, depending on the ratio of the sizes and structure of sections of the bar elements, as well as the ratio of the forces acting in them.

scholarly journals DEFORMATION ANALYSIS OF LAYERED REINFORCED CONCRETE - FOAM CONCRETE FLOOR SLABS

2020 ◽  
Vol 60 (4) ◽  
pp. 324-337
Author(s):  
Oksana Lytvyniak
Keyword(s):  
Reinforced Concrete ◽  
Cross Section ◽  
Strain State ◽  
Deformation Analysis ◽  
Calculated Cross Section ◽  
Foam Concrete ◽  
Deformation Method ◽  
Stress Strain ◽  
Stress Strain State ◽  
Floor Slabs

This article presents a theoretical study of a stress-strain state of layered reinforced concrete - foam concrete floor slabs (hereinafter called as the LRFCS), with the use of a deformation analysis. Compressive and tensile diagrams of the foam concrete, a tensile diagram of the reinforced concrete and compressive and tensile diagrams of the reinforcement rod are used for the estimation of the stress-strain state of the calculated cross-section of the LRFCS. It should be noted that this article presents the deformation method of loading by the scheme of pure bending for the LRFCS. This deformation method of loading is determined by six shapes of the stress-strain state. These shapes of the stress-strain state are represented by the corresponding distribution diagrams of the relative deformations and the distribution diagrams of internal stresses in the calculated cross-section of the floor slab. Also, this article presents the corresponding equilibrium equations of internal efforts and moments, which act in the calculated cross-section of the floor slab for all shapes of its stress-strain state. Consequently, the mentioned recommendations and mathematical dependencies allow to evaluate the stress-strain state of the LRFCS from its initial loading to its destruction.

scholarly journals ASSESSMENT OF CARRYING CAPACITY OF THE ROUND IN PLAN REINFORCED CONCRETE FOUNDATION FOR THE SILO

2021 ◽  
pp. 28-37
Author(s):  
Yu. Vybranets ◽  
◽  
S. Vikhot ◽  
S. Burchenya ◽  
I. Babyak ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Strain State ◽  
Technical Condition ◽  
Normal Operation ◽  
Structural Safety ◽  
Building Structures ◽  
Structural Elements ◽  
Safe Operation ◽  
Stress Strain ◽  
Stress Strain State

During the design, installation and operation of silos, they have defects and damage of various kinds, which affect the stress-strain state and durability of structural elements. Timely inspections and determination of technical conditions of structural elements of the structure and the site as a whole, will establish the possibility of its further safe operation or the need to restore operational properties by ensuring structural safety and reliability of structures. Therefore, the development of design schemes, methods of calculating the stress-strain state, life expectancy and further reinforcement for round reinforced concrete elements of silos with local damage, is quite relevant. Improper maintenance and operation of structural elements, as well as errors in the design and installation in the future lead to unusable for normal operation and sometimes an emergency. The development of projects to strengthen existing structures is a very responsible matter. The most common solution for strengthening existing foundations is to increase the area of support of the foundation cushion, which is not always possible in a compact building. The purpose of the work is to determine the technical condition of the building structures of the silo and the results of calculations performed in the PC Lira, to offer options for strengthening the foundation on a specific example. Structural solutions of the reinforced concrete monolithic foundation of the silo, the main defects and damages determined by the technical condition of the structure are given. For further safe operation of the structure, it is recommended to reinforce the wall foundations by gluing composite tapes and perform reinforcement of the foundations by controlling the growth of piles in accordance with the additional working design of the structure reinforcement. If the latest recommendations on strengthening and adhering to the safe and reliable operation of construction and structures are followed, further operation of building structures will be safe.

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 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.

Sign in / Sign up

Export Citation Format

Share Document