Experimental Studies of Reinforced Concrete Beams Using Embedded Steel Trusses

2016 ◽  
Vol 113 (4) ◽  
Author(s):  
Nan Zhang ◽  
Chung C. Fu ◽  
Liang Chen ◽  
Lu He
Author(s):  
O. Radaikin ◽  
L. Sharafutdinov

The purpose of the study is to experimentally study the joint work of steel fiber reinforced concrete (SFB) reinforcement jacket and reinforced concrete beams at all stages of loading to further develop a methodology for calculating this method of reinforcing bending elements. The main results of the study consist in assessing the strength, stiffness, fracture toughness, as well as the nature of fracture with a picture of the development of cracks for the examined 4 samples (two with a jacket of reinforcement, two - control - without reinforcement). It has been established that the use of SFB jacket with a thickness of 45 mm and with a fiber content percentage of 2,5% (at a flow rate of 196 kg/m3) increases the breaking load by 20 %, stiffness from 3,4 to 11 times as it is loaded, crack resistance 2,4-2,8 times. The results are compared with computer modeling in ANSYS PC: the discrepancy in the load of crack formation, fracture and deflection values for full-scale samples and a computer model are within 6,3 %, which indicates the reliability of the numerical results and the possibility of using the proposed computer models in further studies on topic of the article.


2019 ◽  
pp. 4-12 ◽  
Author(s):  
V. V. Bardakov ◽  
A. I. Sagaydak ◽  
S. V. Elizarov

The paper presents the results of the conducted experimental studies on three-point bend testing of over-reinforced concrete beams with incremental cyclic load, up to destruction, using the acoustic emission method. In total 3 RC beams differ from each other in reinforcement type, concrete composition and ultimate load were tested. Special attention is paid to the investigation of the relationship between destructive processes occurring during the testing of reinforced concrete beams and the evolution of acoustic emission data registered during the test. The analysis described in the article makes it possible, on the basis of acoustic emission data, recorded during the tests, to distinguish the stages corresponding to the different technical state of over-reinforced concrete structures.


2012 ◽  
Vol 5 (3) ◽  
pp. 343-361
Author(s):  
M. R. Garcez ◽  
G. L. C. P. Silva Filho ◽  
Urs Meier

Different FPR post-strengthening techniques have been developed and applied in existing structures aiming to increase their load capacity. Most of the FRP systems used nowadays consist of carbon fibers embedded in epoxy matrices (CFRP). Regardless of the advantages and the good results shown by the CFRP post-strengthen technique, experimental studies show that, in most cases, the failure of post-strengthened structures is premature. Aiming to better use the tensile strength of the carbon fiber strips used as post-strengthening material, the application of prestressed CFRP strips started to be investigated. The main purpose of this paper is to analyze the effects of the composite prestressing in the performance of the CFRP post strengthening technique. The experimental program was based on flexural tests on post-strengthened reinforced concrete beams subjected to static - part 1 and cyclic - part 2 loading. Experimental results allowed the analysis of the quality and shortcomings of post-strengthen system studied, which resulted in valuable considerations about the analyzed post-strengthened beams.


2017 ◽  
Vol 7 (4) ◽  
pp. 9-13
Author(s):  
Denis A. PANFILOV ◽  
Vladimir Yu. CHEGLINTSEV ◽  
Vyacheslav V. ROMANCHIKOV ◽  
Yury V. ZHILTSOV

In this paper theoretical studies of statically determinated bending reinforced concrete beams of rectangular cross-section on deformation indexes under the eff ect of a short-time uniformly distributed load are viewed. These theoretical studies are based on the main points of the nonlinear deformation model that takes into account the nonlinear work of concrete and fi tments taking into account discrete cracking. The results of calculating the deformation of beams by the method of SP 63.13330.2012 and by authors’ method are proposed as well as the results of a numerical experiment with the identifi cation of the stress-strain state of statically determinated beams in the form of a fi nite element model in the program complex «Lira CAD-2017R3» using a linear and non-linear sett ing of characteristics of concrete and reinforcement. Based on the results of theoretical studies, the calculation results by the methodology of the current standard with a numerical experiment, as well as with the authors’ calculation methodology are compared. All calculations and loading schemes in this technique are given taking into account the possibility of further experimental studies.


2021 ◽  
Vol 243 ◽  
pp. 112539
Author(s):  
Xiaoxia Yang ◽  
Haotian Yuan ◽  
Chao Li ◽  
Lei Wu ◽  
Peijun Wang ◽  
...  

2021 ◽  
Vol 3 (72) ◽  
pp. 34-37
Author(s):  
A. Abdullaev .

Experimental studies have been carried out to study the effect of longitudinal compression on the strength of the wall of I-beams of reinforced concrete beams.It has been established that with the central application of a longitudinal compressive force, the strength of the wall of I-beams of reinforced concrete beams with an alternating diagram of bending moments in the zone of action of transverse forces practically depends little on the degree of longitudinal compression.A comparative analysis of the results obtained with the results of similar experimental studies carried out on I-beam reinforced concrete beams with an unambiguous diagram of bending moments in the zone of action of shear forces is carried out.


2020 ◽  
Vol 4 (157) ◽  
pp. 18-24
Author(s):  
O. Romashko-Maistruk

This article is devoted to the study of the main patterns of normal cracks multilevel formation in reinforced concrete elements and structures. A critical analysis of the latest publications related to the theme of these studies is carried out. The classification is carried out and the main shortcomings of the known works on the four identified areas of research are identified. The most important elements of the method of reinforced concrete beams experimental research are developed and briefly described. The main characteristics of the prototypes, the conditions for their manufacture and storage are given. The most important results of testing reinforced concrete beams, concerning the main parameters and characteristics of level formation and crack disclosure are highlighted. It was confirmed that the process of normal cracks formation is indeed multilevel and is accompanied by a gradual disruption of the bond between reinforcement and concrete. According to the results of experimental studies, it has been established that in the real design of bending reinforced concrete elements, when calculating their crack resistance, it is possible to restrict oneself to only 2 levels of normal cracking. The calculation of the step and normal cracks opening width in beams research was carried out according to the real multilevel and traditional "one-level" schemes of their formation. These calculations were carried out according to the author's general and simplified methods, according to a method that uses a linear function of the average adhesion stresses of reinforcement with concrete, according to the methods of current domestic and European standards and building rules. Their statistical comparison with the experimental studies results confirmed the effectiveness of those calculation methods in which the crack formation step is directly related to the basic laws and parameters of reinforcement to concrete adhesion. The results of this comparison showed that the author's general method, based on the use of a nonlinear function of the reinforcement with concrete average adhesion stresses, turned out to be the most accurate. Keywords: reinforced concrete, elements, adhesion, reinforcement, cracks, levels of formation, step, width.


2021 ◽  
Vol 27 (4) ◽  
pp. 242-247
Author(s):  
Nadiia Kopiika ◽  
Pavlo Vegera ◽  
Rostyslav Vashkevych ◽  
Zinoviy Blikharskyy

Abstract Each structure is exposed to different influences during operation. As a result, there are various defects and damages of these elements that affect their safe operation. The article presents the results of experimental studies of reinforced concrete beams with damages to stretched reinforcement made with and without initial load application. As the damages were accepted one or five Ø5.6 mm holes. In one case, the damage was made until the beam destruction (up to the 8.4 mm opening) Control samples of both series were destroyed due to crushing of the compressed zone of concrete. Samples that were damaged without initial loading collapsed due to rupture of the stretched reinforcement. The same type of failure was identified for damages at the operational load level.


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