RELIABILITY ANALYSIS OF REINFORCED CONCRETE FLEXURAL ELEMENT ON CRACKING BASED ON FRACTURE MECHANICS

2020 ◽  
pp. 40-44
Author(s):  
S. A. Solov’ev ◽  
O. V. Yarygina
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
Stress Intensity ◽  
Fracture Mechanics ◽  
Reliability Analysis ◽  
Critical Stress ◽  
Intensity Coefficient ◽  
Concrete Compressive Strength ◽  
Concrete Element ◽  
Stress Intensity Coefficient

The article describes a probabilistic approach to the reliability analysis of a flexural reinforced concrete element by the cracking criterion using the provisions of fracture mechanics. Two mathematical models of limit state are proposed for reliability analysis: with the evaluation of the critical stress intensity coefficient directly and through the design concrete compressive strength. On the basis of regression analysis, the relationship between the critical stress intensity coefficient and the design concrete compressive strength is established which can be used in the inspection of reinforced concrete structural elements. The influence of the design concrete compressive strength on the failure (cracking) probability of the flexural reinforced concrete element is analyzed. The numerical example of reliability analysis is given for the reinforced concrete beam by the criterion of cracking. It is noted that the required level of reliability should be set for each structural object individually based on the acceptable risk value using economic and non-economic losses.

scholarly journals A PROBABLISTIC APPROACH TO EVALUATION OF THE ULTIMATE LOAD ON FLEXURAL RC ELEMENT ON CRACK LENGTH

2020 ◽  
Vol 16 (1) ◽  
pp. 98-105
Author(s):  
Sergey Solovyev
Keyword(s):  
Reinforced Concrete ◽  
Stress Intensity ◽  
Crack Length ◽  
Reliability Analysis ◽  
Critical Stress ◽  
Probabilistic Approach ◽  
Structural Elements ◽  
Intensity Coefficient ◽  
Stress Intensity Coefficient ◽  
Concrete Elements

The fracture mechanics of concrete and reinforced concrete is a promising direction in the development of methods for reinforced concrete structural elements design and inspection. At the same time, probabilistic methods of design and behavior analysis of structural elements are of particular interest. The article describes a probabilistic approach to load-bearing capacity and reliability analysis of flexural reinforced concrete elements based on the crack length criterion. The functional relationship between the critical stress intensity coefficient of concrete and the design compressive strength of concrete is given. The article presents a method for the reliability analysis of flexural reinforced concrete elements at the operational stage with limited statistical data about the critical stress intensity coefficient of concrete. The ultimate value of the failure probability (or reliability index) should be set for each object individually based on the value of the acceptable risk.

Application of the ultrasound control to evaluation of the crack-resistance of low-carbon martensite steel 07Kh3GNMYuA

2021 ◽  
Vol 87 (1) ◽  
pp. 45-51
Author(s):  
R. A. Vorob’ev ◽  
V. N. Litovchenko
Keyword(s):  
Heat Treatment ◽  
Stress Intensity ◽  
Crack Resistance ◽  
Critical Stress ◽  
Mechanical Characteristics ◽  
Intensity Coefficient ◽  
Acoustic Characteristics ◽  
Stress Intensity Coefficient ◽  
The Impact

The goal of the study is to reveal the impact of change in the structural state of steel 07Kh3GNMYuA after heat treatment on the values of the critical stress intensity coefficient (K1c) obtained at a temperature of 50°C and on the velocity of ultrasound wave propagation, as well as to determine a correlation between them for rapid assessment of the crack resistance using acoustic characteristics. The mechanical characteristics of the material and the critical stress intensity coefficient K1c were obtained on the test machine «Inspekt 100 Table». The tangent method is used for determination of K1c. Three samples per K1c value were used in the experiment for a three-point bending scheme at the operating temperature T = –50°C. Acoustic parameters were measured using the echo-pulse method. The results of ultrasonic scanning of heat-strengthened samples made of steel 07Kh3GNMYuA demonstrated the possibility of non-destructive quantitative evaluation of the critical stress intensity coefficient. New data on the mechanical properties of steel 07Kh3GNMYuA and on the correlation between the velocity of longitudinal elastic waves and the values of the critical stress intensity coefficient of structures were obtained. Deviation of the calculated values of K1c obtained using acoustic measurements from the experimental values does not exceed 10%. The proposed model, which explains change in the acoustic characteristics of steel 07Kh3GNMYuA on the basis of phase changes occurring in the steel structure upon tempering, provides conducting of similar studies for other modes of heat treatment and other steel grades. The method is a low labor- and time-consuming procedure for determination of the mechanical characteristics of the products made of steel 07Kh3GNMYuA, since it does not require the manufacturing of samples and their testing. The developed procedure can be proposed for manufacturing application, as the main or additional method for evaluation of the mechanical parameters of materials after various modes of heat treatment.

Critical Stress Intensity Coefficient at Transverse Shear for Nanofibrobeton

2021 ◽  
pp. 41-47
Author(s):  
E.A. SADOVSKAYA ◽  
E.N. POLONINA ◽  
S.N. LEONOVICH ◽  
S.A. ZHDANOK ◽  
V.V. POTAPOV
Keyword(s):  
Stress Intensity ◽  
Transverse Shear ◽  
Critical Stress ◽  
Intensity Coefficient ◽  
Stress Intensity Coefficient

Monte Carlo Simulation of the Torsional Strength due to Concrete Compression of Reinforced Concrete Element

2015 ◽  
Vol 797 ◽  
pp. 27-34 ◽  
Author(s):  
Roman Jaskulski ◽  
Piotr Wiliński
Keyword(s):  
Compressive Strength ◽  
Monte Carlo ◽  
Reinforced Concrete ◽  
Cross Sections ◽  
Safety Margin ◽  
Strength Distribution ◽  
Distribution Functions ◽  
Concrete Compressive Strength ◽  
Concrete Element ◽  
Torsional Resistance

The aim of the work was to assess the safety margin of reinforced concrete element of rectangular cross-sections subjected to torsion. In the performed analyses two models of torsional resistance based on concrete compressive strength was taken into account. Assessment was performed with use of Monte Carlo method. Utilized models of shear resistance were taken from formerly used Polish standards: PN-84/B-03264, PN-B-03264:2002 and the actual Polish standard EN-1992-1-1:2004. From the same standards necessary assumptions related with the models were taken. The safety margin and influence of the differences in assumptions on the obtained results were analyzed. The selected models was also evaluated in terms of their “sensitivity” to changes of basic parameters of distribution functions of selected random variables. Results showed that average torsional resistance differs of about 50% times depending of assumed model. The reliability level, measured with the partial reliability exponent ΔR, differs of 10% if different models are concerned but the differences are much higher (up to 5 times, when the standard deviation of concrete compressive strength distribution changes).

scholarly journals Effect of Slag Particle Size on Fracture Toughness of Concrete

2019 ◽  
Vol 9 (4) ◽  
pp. 805 ◽  
Author(s):  
Chung-Ho Huang ◽  
Chung-Hao Wu ◽  
Shu-Ken Lin ◽  
Tsong Yen
Keyword(s):  
Fracture Toughness ◽  
Particle Size ◽  
Compressive Strength ◽  
Stress Intensity ◽  
Fracture Energy ◽  
Critical Stress ◽  
Critical Stress Intensity Factor ◽  
Cementitious Material ◽  
Test Results ◽  
Unique Effect

The effects of particle size of ground granulated blast furnace slag (GGBS) on the fracture energy, critical stress intensity, and strength of concrete are experimentally studied. Three fineness levels of GGBS of 4000, 5000, 6000 cm2/g were used. In addition to the control mixture without slag, two slag replacement levels of 20% and 40% by weight of the cementitious material were selected for preparing the concrete mixtures. The control mixture was designed to have a target compressive strength at 28 days of 62 MPa, while the water to cementitious material ratio was selected as 0.35 for all mixtures. Test results indicate that using finer slag in concrete may improve the filling effect and the reactivity of slag, resulting in a larger strength enhancement. The compressive strength of slag concrete was found to increase in conjunction with the fineness level of the slag presented in the mixture. Use of finer slag presents a beneficial effect on the fracture energy (GF) of concrete, even at an early age, and attains a higher increment of GF at later age (56 days). This implicates that the finer slag can have a unique effect on the enhancement of the fracture resistance of concrete. The test results of the critical stress intensity factor (KSIC) of the slag concretes have a similar tendency as that of the fracture energy, indicating that the finer slag may present an increase in the fracture toughness of concrete.

Guidelines for flexural design of FRP reinforced concrete beams

2020 ◽  
pp. 002199832097373
Author(s):  
Fares Jnaid
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
Carrying Capacity ◽  
Concrete Beams ◽  
Large Diameter ◽  
Reinforced Concrete Beams ◽  
Load Carrying Capacity ◽  
Concrete Compressive Strength ◽  
Load Carrying ◽  
Multiple Variables

This paper investigates the effects of different parameters on the live load carrying capacity of concrete beams reinforced with FRP bars. The author performed a parametric study utilizing an innovative numerical approach to inspect the effects of multiple variables such as reinforcement ratio, concrete compressive strength, span to depth ratio, FRP type, and bar diameter on load carrying capacity of FRP reinforced concrete beams. This study concluded that unless the span to height ratio is smaller than 8, tension-controlled sections are impractical as they do not meet code requirements for serviceability. In addition, it is recommended to use higher reinforcement ratios when using larger span to depth ratios and/or when using CFRP reinforcing bars. Moreover, larger number of bars with small diameter is more practical than fewer large diameter bars. Furthermore, this research suggests that increasing the concrete compressive strength is associated with a significant increase in the ultimate flexural capacity of FRP reinforced beams.

Analysis and Prospect of Size Effect on Normal Section Bearing Capacity of Reinforced Concrete Column

2013 ◽  
Vol 351-352 ◽  
pp. 422-426
Author(s):  
Yong Ping Xie ◽  
Lei Jia ◽  
Gang Sun
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
Theoretical Analysis ◽  
Size Effect ◽  
Bearing Capacity ◽  
Concrete Column ◽  
Concrete Compressive Strength ◽  
Reinforced Concrete Column ◽  
Normal Section

With the development of modern constructional technique, more attention on the size effect is paid by academics and engineers. The normal section bearing capacity of Reinforced Concrete Column is analyzed by eccentrically compressed theory firstly. The size effect on normal section bearing capacity of reinforced concrete column is obtained by theoretical analysis and experimental summary. The size effect formula of concrete compressive strength is proposed. Finally, a research thinking of size effect on bearing capacity is suggested.

Sign in / Sign up

Export Citation Format

Share Document