An experimental study on the within-member variability of in situ concrete strength in RC building structures

Masi, Angelo; Chiauzzi, Leonardo

doi:10.1016/j.conbuildmat.2013.05.102

Cited by 48 publications

(34 citation statements)

References 6 publications

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“…As shown in previous studies [18][19], estimating the CoV fc |N using a small sample of results from concrete core tests may lead to estimates that do not reflect the real variability of the concrete strength. This fact is even more relevant due to the high value of the concrete strength CoV fc |N that is usually found in existing buildings [20][21][22][23], often exceeding a value of 0.20 [24]. A methodology improving the accuracy of the estimate of CoV fc |N by using rebound hammer tests was proposed in [18].…”

Section: Comparison Between the Ec8/3 Cf Values And The Proposed Valuesmentioning

confidence: 99%

“…Given the range of values reported in the literature (e.g. see [20][21][22][23][24]), a CoV fc |N of 0.30 can be considered to be a conservative estimate of the concrete strength variability. According to For the case of reinforcing steel, common values for the CoV|N of the rebar yield strength are generally less than 0.10.…”

Section: Comparison Between the Ec8/3 Cf Values And The Proposed Valuesmentioning

confidence: 99%

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Material strength safety factors for the seismic safety assessment of existing RC buildings

Pereira

Romão

2016

Construction and Building Materials

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h i g h l i g h t sSafety factors are proposed to characterize material strength in existing buildings. The uncertainty due to the number of tests and strength variability are considered. The safety factors are compatible with EC8/3 seismic safety assessment methods. Safety factors and survey plans are defined for concrete compressive strength. Safety factors and survey plans are defined for reinforcing steel yield strength. a r t i c l e i n f o b s t r a c tNew material safety factors (CF mat ) are proposed to characterize material strength in existing buildings. These safety factors are developed in order to be compatible with seismic safety assessment procedures defined by current standards such as Eurocode 8 Part 3. The general theory behind the development of the CF mat safety factors considers the uncertainty associated to the number of surveyed structural elements and the inherent variability of the material strength under analysis. The CF mat safety factors are developed using a finite population approach where the material properties in a building are discretized by considering one value per element. The proposed theory is used to define specific CF mat values and survey plans for the concrete compressive strength and for the reinforcing steel yield strength.

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Section: Comparison Between the Ec8/3 Cf Values And The Proposed Valuesmentioning

confidence: 99%

Section: Comparison Between the Ec8/3 Cf Values And The Proposed Valuesmentioning

confidence: 99%

Material strength safety factors for the seismic safety assessment of existing RC buildings

Pereira

Romão

2016

Construction and Building Materials

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“…Systematic between-member (3) variability and batch-to-batch variability (4) were assumed to be dominant when compared with the other two components [3], despite their known effects (e.g. see [9,14,16]). This fact allows for the definition of a concrete strength discretization criterion where it is assumed that each structural member of the building is represented by a single concrete strength value.…”

Section: Discretizing the Concrete Strength And Disaggregating Its Vamentioning

confidence: 99%

“…Variations of the concrete strength can also be expected within each structural member due to the previously mentioned factors. Moreover, a recent study [9] also described cracking, damage and the selection of the testing positions within the length of a structural element as sources of potential variability.…”

Section: Introductionmentioning

confidence: 99%

Assessment of the concrete strength in existing buildings using a finite population approach

Pereira

Romão

2016

Construction and Building Materials

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h i g h l i g h t sA new method to assess concrete strength in existing building is presented. The method disaggregates the concrete variability into finite populations. The CoV of the concrete strength is evaluated using the CoV of rebound hammer tests. The method controls the uncertainty in the estimate of concrete strength variability. The method controls the uncertainty in the estimate of the mean concrete strength. a r t i c l e i n f o b s t r a c tA framework is defined to evaluate the concrete compressive strength in existing buildings and control the uncertainty associated to the survey planning and to the concrete strength randomness. The framework proposes the discretization and disaggregation of the concrete strength in a building into finite populations of elements. Finite population statistics are used to correlate the number of tests performed in each population with the uncertainty about the mean and the coefficient of variation (CoV) of the concrete strength. A method to estimate the CoV of the concrete strength using the CoV of rebound hammer test results is also proposed to overcome the need for a high number of destructive tests. Results show that the proposed approach effectively controls the uncertainty in the estimate of the variability of the concrete strength in a population as well as the uncertainty in the estimate of the mean value of the concrete strength.

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“…In-situ non-destructive testing (NDT) of concrete structures may target strength estimation of structural concrete either to complete destructive testing or in the absence of drilled cores for laboratory testing [17][18][19][20]. In-situ assessment is frequently initiated by corrosion problems [21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Variability case study based on in-situ rebound hardness testing of concrete. Part 2. Statistical analysis of spatial variability parameters

Borosnyói¹

2014

Epitoanyag - JSBCM

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spatial variographic analysis has been performed on rebound index data collected in-situ at the bottom surface of a concrete floor over 130 m 2 of testing area. Possible use of geostatistical methods in terms of semivariogram, madogram and rodogram analysis was demonstrated. it has been revealed that the classical methods of geostatistics may be further refined for more satisfactory use in the spatial variability analysis of in-situ rebound hardness test results on concrete structures and a possible direction toward the use of empirical estimation of extremal coefficient functions is proposed. keywords: structural concrete; nondestructive testing (nDt); rebound index; spatial variability; variogram Adorján Borosnyói civil engineer (msc), PhD, Associate Professor at Bme Dept. of construction materials and engineering Geology. main fields of interest: cracking and deflection of reinforced concrete, application of non-metallic (FrP) reinforcements for concrete structures, bond in concrete, nondestructive testing of concrete, supplementary cementing materials for high performance concretes, concrete technology. member of the fib task Group 4.1 "serviceability models", corresponding member of riLem technical committee 249-isc "non destructive in situ strength assessment of concrete" and chairman of the szte concrete Division.

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An experimental study on the within-member variability of in situ concrete strength in RC building structures

Cited by 48 publications

References 6 publications

Material strength safety factors for the seismic safety assessment of existing RC buildings

Material strength safety factors for the seismic safety assessment of existing RC buildings

Assessment of the concrete strength in existing buildings using a finite population approach

Variability case study based on in-situ rebound hardness testing of concrete. Part 2. Statistical analysis of spatial variability parameters

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