Energetic damage analysis regarding the fatigue of concrete

Bode, Matthias; Marx, Steffen

doi:10.1002/suco.202000416

Cited by 10 publications

(4 citation statements)

References 17 publications

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“…The energy dissipation for the loading (H) is assumed higher than for (L) in agreement with experimental results presented, e.g. in [47,71]. The left figure outlines a postulate that when the cyclic load changes from the higher level (H) to the lower level (L), the further dissipation profile of the (H-L) scenario can be predicted by switching to the branch observed for the uniform scenario (L).…”

Section: Sequence Of Two Loading Ranges (Ls6)supporting

confidence: 82%

Experimental and theoretical evidence for the load sequence effect in the compressive fatigue behavior of concrete

Baktheer

Chudoba

2021

Mater Struct

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A realistic prediction of the concrete fatigue life exposed to high-cycle loading scenarios with variable amplitudes is of utmost importance for a reliable and economically efficient design of civil engineering infrastructure for transport and energy supply. Current design codes estimate the fatigue life under variable amplitudes using the Palmgren–Miner rule, which assumes a linear scaling between lifetimes measured for uniform cyclic loading scenarios. Several experimental series conducted in the past, however, indicate that this assumption is not valid and that it may lead to unsafe design. In this paper, an experimental and theoretical investigations of the fatigue loading sequence effect in normal- and high-strength concrete behavior are presented, which confirm this observation. In particular, a test campaign with 135 cylinder specimens, including three concrete grades and six different loading scenarios has been conducted. Several response characteristics of the fatigue behavior including Wöhler curves, fatigue creep curves and evolving shapes of hysteretic loops have been evaluated. To substantiate the experimental results, a theoretical explanation of the observed sequence effect is formulated based on the assumption, that energy is dissipated uniformly within the volume of a test specimen during subcritical, compressive cyclic loading. Then, superposition of energy dissipation profiles along the lifetime measured for constant amplitudes becomes possible and a theoretical justification of the experimentally observed sequence effect can be provided. Moreover, a reverse sequence effect reported in the literature for bending fatigue of concrete can then be explained by an unevenly distributed energy dissipation over a cracked specimen. Supported by the theoretical consideration, the processed experimental data is used to validate existing fatigue life assessment rules by testing their ability to reflect the load sequence effect.

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Section: Sequence Of Two Loading Ranges (Ls6)supporting

confidence: 82%

Experimental and theoretical evidence for the load sequence effect in the compressive fatigue behavior of concrete

Baktheer

Chudoba

2021

Mater Struct

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“…As shown in many investigations, for example, Refs. [6–9], the temperature often rises at high frequencies over the entire test duration. The storage is carried out according to Ref.…”

Section: Discussionmentioning

confidence: 99%

“…[2–5]. Systematic investigations on UHPC and HPC as well as high‐strength grouting mortars showed an influence on the fatigue strength, 6–10 in which the calculated expected values according to the Model Code 2010 11 were partly not achieved. Figure 1 shows test results with HPC and UHPC from Ref.…”

Section: Introductionmentioning

confidence: 99%

Influence of temperature on the compressive strength of high performance and ultra‐high performance concretes

Deutscher

Markert

Scheerer

2021

Structural Concrete

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The heating up of high-performance concretes under fatigue load in cyclic pressure threshold test raises the question of the mechanisms and influences of this heat development. Of particular interest is how the heating affects the fatigue strength and what the causes of this are. In order to be able to answer this basically, two test series-one with an HPC and one with a UHPC-were carried out in which the temperature influence on the static compressive strength in a range of À25 C to 90 C was determined. In addition, different storage conditions are being considered in order to question previous findings. In this article, the state of the art is briefly presented and the test program based on it. Then, the production and storage of the specimen, their preparation and the used measurement technique are explained. The results obtained are presented with regard to concrete strength, type of storage, moisture content and, in the main part, the influence of temperature. A discussion of the results in relation to the state of knowledge follows. General insights are acquired, which will be very helpful for further work in the field of fatigue research on high performance concretes.

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“…In several research papers, a temperature increase in the sample was measured during testing [3][4][5][6][7][8][9], which usually resulted in an earlier failure, compared to the expected values according to fib Model Code 2010 [10] or to slowly cycled attempts [7,9,[11][12][13][14][15]. In the recent past, detailed parameter studies have been carried out in various parallel research projects [11][12][13][14][15][16][17][18]. For one UHPC, the load-related parameters such as the relation between lower and upper stress levels and frequency as well as the parameters of maximum grain size, concrete strength, and concrete age were investigated regarding concrete heating, as in the project presented here and already published in [13,16,[19][20][21].…”

Section: Introductionmentioning

confidence: 99%

Consideration of the Heating of High-Performance Concretes during Cyclic Tests in the Evaluation of Results

Deutscher

2021

Applied Mechanics

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Material-efficient, highly load-bearing members made of high-performance compressive concretes are often exposed to cyclical loads because of their slender construction, which can be relevant to the design. When investigating the fatigue behaviour of high-performance concretes in pressure swell tests, however, the specimen temperature rises strongly owing to the elevated loading rate at frequencies higher than 3 Hz. This leads to a negative influence on the achieved number of load cycles compared to tests carried out at slow speeds and calculated values, for example, according to fib Model Code 2010. This phenomenon, which was already observed, must be considered when generating design formulae or Wöhler lines for component design, as the test conditions with high constant load frequencies as well as sample storage in a climate chamber at constant conditions are prerequisites that cannot be expected in real material applications. Therefore, laboratory testing influences must be eliminated in order to avoid underestimating the material. Instead of adjusting the test conditions to prevent or control temperature development, as was the case in previous approaches, this article shows how the temperature effects can be corrected when analysing the results, considering both the applied stress and the maximum temperature reached. For this purpose, a calculation method was developed that was validated on the basis of a large number of fatigue tests. Thus, in the future, the application of one temperature sensor to the test specimen can effectively advance the extraction of values for Wöhler curves, even with high test frequencies.

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Energetic damage analysis regarding the fatigue of concrete

Cited by 10 publications

References 17 publications

Experimental and theoretical evidence for the load sequence effect in the compressive fatigue behavior of concrete

Experimental and theoretical evidence for the load sequence effect in the compressive fatigue behavior of concrete

Influence of temperature on the compressive strength of high performance and ultra‐high performance concretes

Consideration of the Heating of High-Performance Concretes during Cyclic Tests in the Evaluation of Results

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