DYNAMIC STRENGTH CRITERIA OF PRESTRESSED REINFORCED CONCRETE STRUCTURES WITH COMBINED STRENGTH

2021 ◽  
Vol 97 (5) ◽  
pp. 51-61
Author(s):  
T.A. ILIUSHCHENKO ◽  
◽  
N.V. FEDOROVA ◽  
◽  
Keyword(s):  
Reinforced Concrete ◽  
Crack Resistance ◽  
Dynamic Strength ◽  
Dynamic Effect ◽  
Reinforced Concrete Frame ◽  
Concrete Element ◽  
Strength Criteria ◽  
Concrete Frame ◽  
General Terms ◽  
Principal Axes

Dynamic strength criteria and crack resistance criteria are given for a typical plane-stressed reinforced concrete element with prestressed reinforcement in one direction. The criteria are constructed by generalizing the theory of plasticity of concrete and reinforced concrete G.A. Geniev on the area of existence of tensile stresses: "tension- tension" and "compression- tension". In general terms, the crack resistance condition and strength condition of a prestressed reinforced concrete plane-stressed element are presented in the form of an ellipse in the coordinates of the main stresses. In this case, in contrast to the criteria of crack resistance of a flat unstressed element, the principal axes of the ellipse don’t pass through the origin. The results of a comparative analysis of the calculated and experimental data on crack resistance and strength for prestressed reinforced concrete in the support zone of the beam of a monolithic reinforced concrete frame tested for a given design load and a special dynamic effect are given.

scholarly journals COMPUTER TECHNOLOGIES IN THE FORMATION OF COMPUTED MODELS OF MONOLITHIC REINFORCED CONCRETE STRUCTURES

2017 ◽  
Vol 13 (4) ◽  
pp. 37-46 ◽  
Author(s):  
Anatoliy I. Bedov ◽  
Aleksandr S. Salov ◽  
Azat I. Gabitov ◽  
Dmitriy М. Kuznetsov ◽  
Elza A. Sadykova
Keyword(s):  
Reinforced Concrete ◽  
Analytical Models ◽  
Structural Elements ◽  
Reinforced Concrete Frame ◽  
Concrete Element ◽  
Concrete Frame ◽  
Numerical Studies ◽  
Deformation State ◽  
Rational Combination ◽  
The Relationship

The areas of application of concrete and reinforcement of higher grades for strength in structural elements of a monolithic reinforced concrete frame are considered. Analytic dependencies, criteria and boundary conditions are proposed that numerically describe the relationship between increasing the strength of concrete and reducing the consumption of reinforcing steel for bent and compressed-bent elements. Calculation-analytical models of the deformation state of overlaps of a monolithic reinforced concrete multi-storey frame have been developed on the basis of multifactor numerical studies carried out for various values of the thicknesses of ceilings, spans, operating loads, classes of concrete and reinforcement. Calculated parameters of slabs are determined, which determine their bearing capacity. On the basis of computer technology, the optimum section of a reinforced concrete element is modeled according to the criterion of reducing the material consumption and rational combination of classes of concrete and reinforcement.

scholarly journals Determination of dynamic durabilities and dynamic strength of armature in the elements of the constructive system at its flash structural restructuring

2018 ◽  
Vol 251 ◽  
pp. 02009
Author(s):  
Nataliya Fedorova
Keyword(s):  
Reinforced Concrete ◽  
Dynamic Strength ◽  
Structural System ◽  
Reinforced Concrete Frame ◽  
Structural Reorganization ◽  
Concrete Frame ◽  
Half Wave ◽  
Rod System ◽  
Emergency Actions

The results of modeling and computational analysis of the static-dynamic deformation of the reinforced concrete frame-and-rod system are presented for special emergency actions caused by the sudden removal of one of the supporting elements. On the basis of energy, without the apparatus of the dynamics of structures, analytical dependences are constructed to determine the increments of the dynamic extensions in the stretched armature and the dynamic strength of the reinforcement in the sections of the frame elements under the indicated effects on the first half-wave of the structure's oscillations. Verification of the proposed analytical dependencies is performed by comparing the theoretical values of the calculated parameters with the experimental data. It is shown that the constructed analytical dependencies allow to determine quite strictly the investigated dynamic parameters of deformation of the loaded reinforced concrete framed structural systems of buildings and structures under their dynamic overloading by special emergency action associated with sudden structural reorganization of the structural system.

CRACK RESISTANCE OF PRESTRESSED REINFORCED CONCRETE FRAME STRUCTURE SYSTEMS UNDER SPECIAL IMPACT

2021 ◽  
Vol 93 (1) ◽  
pp. 74-84
Author(s):  
T.A. ILIUSHCHENKO ◽  
◽  
V.I. KOLCHUNOV ◽  
S.S. FEDOROV ◽  
◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Crack Resistance ◽  
Impact Analysis ◽  
Progressive Collapse ◽  
Frame Structure ◽  
Frame Structures ◽  
Reinforced Concrete Frame ◽  
Resistance Development ◽  
Concrete Frame ◽  
Before And After

The results of experimental and theoretical researches of crack resistance, development and growth of cracks of a fragment of a reinforced concrete multi-storey frame of a monolithic building with prestressed beams for a special emergency impact caused by a sudden removal of one of the load-bearing elements are presented. Removal of the middle column of the frame was considered as an emergency impact. Analysis of the pattern cracking in the frames with a prestressed beam before and after a special impact is carried out against the pattern cracking in an unstressed frame structure. Based on the increments of cracks width in the beam, the coefficient of dynamic additional loading in prestressed frame structures from a special impact was calculated. The obtained results of experimental and theoretical researches of the crack resistance of frame structures in considered influences can be used in the development of methods for protecting the frames of monolithic multi-storey buildings against progressive collapse.

scholarly journals Shear Behavior of a Reinforced Concrete Frame Retrofitted with a Hinged Steel Damping System

2020 ◽  
Vol 12 (24) ◽  
pp. 10360
Author(s):  
Hyun-Do Yun ◽  
Sun-Woong Kim ◽  
Wan-Shin Park ◽  
Sun-Woo Kim
Keyword(s):  
Reinforced Concrete ◽  
Shear Behavior ◽  
Seismic Retrofitting ◽  
Reinforced Concrete Frame ◽  
Main Research ◽  
Torsion Spring ◽  
Concrete Frame ◽  
Energy Dissipation Capacity ◽  
Research Questions ◽  
Torsion Springs

The purpose of this study was to experimentally evaluate the effect of a hinged steel damping system on the shear behavior of a nonductile reinforced concrete frame with an opening. For the experimental test, a total of three full-scale reinforced concrete frame specimens were planned, based on the “no retrofitting” (NR) specimens with non-seismic details. The main research questions were whether the hinged steel damping system is reinforced and whether torsion springs are installed in the hinged steel damping system. From the results of the experiment, the hinged steel damping system (DR specimen) was found to be effective in seismic retrofitting, while isolating the opening of the reinforced concrete (RC) frame, and the torsion spring installed at the hinged connection (DSR specimen) was evaluated to be effective in controlling the amount of deformation of the upper and lower dampers. The strength, stiffness, and energy dissipation capacity of the DSR specimen were slightly improved compared to the DR specimen, and it was confirmed that stress redistribution was induced by the rotational stiffness of the torsion spring installed in the hinge connection between the upper and lower frames.

Deformation Characteristics of Reinforced Concrete Beam-Column Joint Cores under Earthquake Loading

2003 ◽  
Vol 6 (1) ◽  
pp. 15-21 ◽  
Author(s):  
Sayed A. Attaalla ◽  
Mehran Agbabian
Keyword(s):  
Reinforced Concrete ◽  
Shear Deformation ◽  
Concrete Beam ◽  
Reinforced Concrete Beam ◽  
Reinforced Concrete Frame ◽  
Bond Failure ◽  
Strain Compatibility ◽  
Concrete Frame ◽  
Column Joint ◽  
Reinforced Concrete Frame Structures

The characteristics of the shear deformation inside the beam-column joint core of reinforced concrete frame structures subjected to seismic loading are discussed in this paper. The paper presents the formulation of an analytical model based on experimental observations. The model is intended to predict the expansions of beam-column joint core in the horizontal and vertical directions. The model describes the strain compatibility inside the joint in an average sense. Its predictions are verified utilizing experimental measurements obtained from tests conducted on beam-column connections. The model is found to adequately predict the components of shear deformation in the joint core and satisfactorily estimates the average strains in the joint hoops up to bond failure. The model may be considered as a simple, yet, important step towards analytical understanding of the sophisticated shear mechanism inside the joint and may be implemented in a controlled-deformation design technique of the joint.

Resistance of Reinforced Concrete Frames with Masonry Infill Walls to In-Plane Vertical Loading

2016 ◽  
Vol 711 ◽  
pp. 982-988
Author(s):  
Alex Brodsky ◽  
David Z. Yankelevsky
Keyword(s):  
Reinforced Concrete ◽  
Failure Modes ◽  
Progressive Collapse ◽  
Lateral Loading ◽  
Masonry Walls ◽  
Reinforced Concrete Frame ◽  
Masonry Infill ◽  
Concrete Frame ◽  
Vertical Loading ◽  
Infill Masonry

Numerous studies have been conducted on the in plane behavior of masonry infill walls to lateral loading simulating earthquake action on buildings. The present study is focused on a problem that has almost not been studied regarding the vertical (opposed to lateral) in-plane action on these walls. This may be of concern when a supporting column of a multi-storey reinforced concrete frame with infill masonry walls undergoes a severe damage due to an extreme loading such as a strong earthquake, car impact or military or terror action in proximity to the column. The loss of the supporting column may cause a fully or partly progressive collapse to a bare reinforced concrete frame, without infill masonry walls. The presence of the infill masonry walls may restrain the process and prevent the development of a progressive collapse. The aim of the present study is to test the in-plane composite action of Reinforced Concrete (RC) frames with infill masonry walls under vertical loading through laboratory experiments and evaluate the contributions of infill masonry walls, in an attempt to examine the infill masonry wall added resistance to the bare frame under these circumstances. Preliminary results of laboratory tests that have been conducted on reinforced concrete infilled frames without a support at their end, under monotonic vertical loading along that column axis will be presented. The observed damages and failure modes under vertical loading are clearly different from the already known failure modes observed in the case of lateral loading.

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