Extended Abstracts of the 16th International Probabilistic Workshop 2018 in Vienna

Strauß, Alfred; Bergmeister, Konrad; Proske, Dirk; Bergmann, Sarah; Hegger, Josef; Ricker, Marcus; Rempel, Sergej; Kalogeraki, C.; Gakis, Angelos; Landi, Filippo; Friedman, Noémi; Croce, Pietro; Pan, Lixia; Lehký, David; Novák, Drahomı́r; Slowik, Ondřej; Spyridis, Panagiotis; Stephani, Alexander; Coile, Ruben Van; Khorasani, Negar Elhami; Gernay, Thomas; Hopkin, Danny; Marsili, Francesca; Bödefeld, Jörg; Daduna, Hans; Talarico, Luca; Reniers, Genserik; Gelder, Pieter van; Sousa, Hélder S.; Matos, José C.; Branco, Jorge M.; Lourenço, Paulo B.; Machado, José S.; Pereira, Filipe; Tran, Ngoc Linh; Graubner, Carl‐Alexander; Šomodíková, Martina; Hopkin, Charlie; Fu, Ian; Spearpoint, Michael; Molod, Mohammad Amin; Barthold, Franz‐Joseph; Šimonová, Hana; Lipowczan, Martin; Kucharczyková, Barbara; Keršner, Zbyněk; Sauer, Axel; Olfert, Alfred; Körte, Lisa; Ortlepp, Regine; Mold, Lisa; Krug, Bernhard; Frangopol, Dan M.; Jung, Karel; Marková, Jana; Sýkora, Milan; Zou, Guang Ping; Banisoleiman, Kian; González, Arturo Galán; Márföldi, Monika; Sokol, Milan; Lamperová, Katarína; Venglár, Michal

doi:10.1002/best.201800059

Cited by 5 publications

(5 citation statements)

References 5 publications

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“…with adequate aggregate proportioning, proper aggregate quality and proper water/cement ratio. Looking at the test results from the scientific literature [18,[35][36][37][38][39][40][41] we can see that test data show a dispersion similar to the one showed in figures 7 and 8.…”

Section: Discussionmentioning

confidence: 56%

“…This is an unexpected outcome since most of the references (see [18] and [35] for a comprehensive review and [20] and [36] for an up-to-date code approach) on modern concrete shows that the core-to-cubic strength ratio increases as the concrete class increases, such as in figure 7 for [38] among the others. In figures 7 and 8 other data are represented: in [36] the core-to-cubic strength is reported to lie in-between 0.8 and 0.87, in [39], on the basis of a data set of 640 tests, the average ratio is identified as 0.84 (ranging from 0.60 to 1.00) independent on the concrete strength. The line set at the level 0.70 originates simply from two common code provisions [20, 36 and 37]: cylindrical strength as 0.83 times the cubic one and the core strength 0.85 times the cylindrical one, so that 0.03x0.85=0.705≅0.70.…”

Section: Test Resultsmentioning

confidence: 99%

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Core-to-Cubic Strength Ratio for Historical-Like Concrete

Brencich¹,

Hasweh²,

Pera³

2021

cea

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Coring is considered to provide the best estimate of concrete compressive strength in existing structures and is commonly used to calibrate Non-Destructive and Moderately Destructive Techniques. Historical concrete, produced in the pre-code period until the '20s, significantly differs from modern concrete due to lack of standardization, improper rules of thumbs and to aggregate shape (round, smooth and often excessively large aggregates) and proportioning. Therefore, the applicability of the procedures calibrated on modern concrete to a historical one, also coring, is an issue that needs to be discussed. In this paper, an experimental campaign on historical-like concrete, i.e. with the same defects as historical concrete, aims at identifying the reliability of drilled cores due to the effect of round aggregates. The results show that standard procedures commonly used on modern concrete cannot be directly applied to historical concrete: drilled cores suffer from scale effects (core diameter) and from cutting damage of the material much more than modern concrete. In detail, the core-to-cubic ratio, that modern codes assume in the range 0.70-0.85, due to the dimension and shape of the aggregates is found inside a larger range, 0.70-1.00, and, as opposed to modern concrete, is found to be decreasing as concrete strength increases. Besides, the diameter of the core is found to have a relevant effect on the estimate of the material compressive strength and on the core-to-cubic strength ratio, pointing out that the dimension of the core affects the results much more than for modern concrete. This latter result, which needs further research, points out that historical concretes may be rather different from modern ones and probably need larger cores to be drilled than modern concrete due to the larger dimension of aggregates that are often found in pre-code concrete.

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Section: Discussionmentioning

confidence: 56%

Section: Test Resultsmentioning

confidence: 99%

Core-to-Cubic Strength Ratio for Historical-Like Concrete

Brencich¹,

Hasweh²,

Pera³

2021

cea

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“…Table 1 provides the weights b i of elements according to ISO 9224, the representative compositions of mild steels and grey cast irons and respective regression coefficients b in eqn (2). The negative values of b-coefficient for the two representative compositions of grey cast irons [4,5] clearly demonstrate that eqn (2) along with the weights b i recommended in ISO 9224 cannot be used to predict corrosion losses of grey cast irons. Negative b-values lead to the unrealistic predictions when corrosion loss decreases with time.…”

Section: Corrosion Rates Based On the Models For Mild Steelsmentioning

confidence: 99%

“…In the second example, a thin-walled short cast iron column supporting a roof of a historic arbour [4,14] is analysed (Ø = 114 mm, thickness of 12.5 mm, Ø in = 89 mm). In this case, the uncertainty in resistance slightly increases due to uncertainty in corrosion losses that is taken into account in reliability analysis.…”

Section: Thin-walled Columnmentioning

confidence: 99%

Corrosion of historic grey cast irons: indicative rates , significance, and protection

Sýkora¹,

Kreislová²,

Pokorný³

2020

Int. J. CMEM

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In Europe many buildings and machinery in industrial sites are recognised as cultural heritage. These structures, often made from various types of irons or historic steels, have been for decades or centuries exposed to aggressive atmospheric environments and suffered from corrosion attack. The contribution discusses corrosion rates, the effects of corrosion on structural reliability, and the efficiency of surface treatments. The model for corrosion rates of historic metals cannot be based on the degradation model for mild steels even though specific features of historic alloys such as increased content of carbon and different chemical composition would be taken into account. realistic estimates of corrosion rates need additionally account for different micro-structure with inputs and different surface properties of historic alloys. This is why the presented model is based on a limited experimental data, considering the corrosivity of environment. The model assumes no corrosion during first seven years of service life and the same type of regression function for the progress period as is provided in ISO 9224 for mild steels and other metals. The effects of repeated applications of paintings are discussed. four principal strategies to the corrosion protection of industrial heritage structures include 'leave as it is', apply temporary protection to reduce degradation progress, apply long term protection, or undertake a complex restoration with replacement of damaged elements. Numerical example indicates that corrosion is normally insignificant for load-bearing iron structures, but may lead to severe problems for thin secondary structural and non-structural members such as railing or decorative elements. The proposed model estimates degradation progress in a mid-term perspective and supports decisions on maintenance of industrial heritage structures.

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“…In order to speed up the computations, a proxy model for the predicted measurable u replacing the G map can be of great use. Taking advantage of functional approximations of the random variables by means of the generalized polynomial chaos (gPC) expansion, the construction of response surfaces is significantly facilitated and a computationally cheap proxy model is obtained [38]. For an extensive review of this topic, please refer to [39].…”

Section: Response Surface Via Generalized Polynomial Chaos Expansionmentioning

confidence: 99%

Probabilistic Seismic Assessment of Existing Masonry Buildings

2019

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The evaluation of seismic performance of existing masonry buildings is a critical issue in assessing the seismic vulnerability of the built environment. With this aim, non-linear static analysis is commonly used, but results are influenced significantly by the collapse criteria adopted, as well as by the assumptions about material properties and drift capacity of masonry walls. A methodology for the probabilistic assessment of the seismic risk index is proposed by means of an original non-linear pushover type algorithm developed by the authors. The main sources of uncertainties related to masonry parameters and their influence on seismic risk indices are identified by means of sensitivity analysis. Response surfaces for the seismic risk indices are thus defined through general polynomial chaos expansion in order to quantify the uncertainties in the resulting seismic risk index. Finally, a seismic performance classification is presented to help stakeholders to manage risks and define priorities for seismic retrofit. The methodology together with the outcomes is illustrated for a set of existing masonry buildings that are part of the school system in the Municipality of Florence.

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Extended Abstracts of the 16th International Probabilistic Workshop 2018 in Vienna

Cited by 5 publications

References 5 publications

Core-to-Cubic Strength Ratio for Historical-Like Concrete

Core-to-Cubic Strength Ratio for Historical-Like Concrete

Corrosion of historic grey cast irons: indicative rates , significance, and protection

Probabilistic Seismic Assessment of Existing Masonry Buildings

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