Combining the bi-objective approach and conditional coring for a reliable estimation of on-site concrete strength variability

2021 ◽  
Vol 54 (6) ◽  
Author(s):  
Zoubir-Mehdi Sbartaï ◽  
Maitham Alwash ◽  
Denys Breysse ◽  
Xavier Romão ◽  
Vincenza A. M. Luprano
Keyword(s):  
Concrete Strength ◽  
Reliable Estimation ◽  
Strength Variability

Assessing concrete strength variability in existing structures based on the results of NDTs

2018 ◽  
Vol 173 ◽  
pp. 786-800 ◽  
Author(s):  
Nuno Pereira ◽  
Xavier Romão
Keyword(s):  
Concrete Strength ◽  
Existing Structures ◽  
Strength Variability

Concrete Strength Variability in Italian RC Buildings: Analysis of a Large DataBase of Core Tests

2014 ◽  
Vol 597 ◽  
pp. 283-290 ◽  
Author(s):  
Angelo Masi ◽  
Andrea Digrisolo ◽  
Giuseppe Santarsiero
Keyword(s):  
Large Scale ◽  
Seismic Vulnerability ◽  
Concrete Strength ◽  
Discrete Distributions ◽  
Existing Buildings ◽  
Large Database ◽  
Public Buildings ◽  
Rc Structures ◽  
Actual Strength ◽  
Strength Variability

The knowledge of the materials’ mechanical properties is a preliminary and important step in the seismic vulnerability assessment of existing buildings. In RC structures, the compressive strength of concrete can have a crucial role on the seismic performance and is usually difficult to estimate. Major seismic codes prescribe that concrete strength has to be determined essentially from in-situ and laboratory tests. In some cases such estimation can be complemented by default values in accordance to standards at the time of construction, therefore analysing the actual concrete properties typically found in RC existing buildings realized in different periods can make available useful data. To this end, in this paper attention has been addressed to public buildings, namely schools and hospitals. A large database made up of about 1500 test results on concrete cores extracted from about 300 RC public buildings located in Basilicata region (Italy), has been prepared and analysed. The relationships between the actual strength values (mean and dispersion) and the construction period of buildings have been studied. Theoretical distributions to approximate the discrete distributions of strength values in different construction periods have been determined, thus providing relevant data for the structural assessment of individual buildings and, especially, for large scale vulnerability evaluations.

Seismic performance sensitivity to concrete strength variability: a case-study

2015 ◽  
Vol 9 (2) ◽  
pp. 321-337 ◽  
Author(s):  
M. De Stefano ◽  
M. Tanganelli ◽  
S. Viti
Keyword(s):  
Seismic Performance ◽  
Concrete Strength ◽  
Performance Sensitivity ◽  
Strength Variability

scholarly journals Analysis of a Large Database of Concrete Core Tests with Emphasis on Within-Structure Variability

Materials ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 1985 ◽  
Author(s):  
Angelo Masi ◽  
Andrea Digrisolo ◽  
Giuseppe Santarsiero
Keyword(s):  
Concrete Strength ◽  
Mean Value ◽  
Large Database ◽  
Concrete Core ◽  
Usual Practice ◽  
Mean Values ◽  
Rc Structures ◽  
Existing Structures ◽  
Design Values ◽  
Strength Variability

In reinforced concrete (RC) structures, the compressive strength of concrete can play a crucial role in seismic performance and is usually difficult to estimate. Major seismic codes prescribe that concrete strength must be determined essentially from in situ and laboratory tests. Mean values obtained from such tests are the reference design values when assessing existing structures under seismic actions. The variability of concrete strength can also play an important role, generally requiring that various homogeneous domains are identified in a single structure, in each of which a specific mean value should be assumed as representative. This study analyzes the inter- and intra-variability of the concrete strength of existing buildings using a very large database made up of approximately 1600 core tests extracted from RC buildings located in the Basilicata region (Southern Italy). The analysis highlighted that concrete strength variability was dependent on the structures’ dimensions as well as on the number of storeys. Moreover, the concrete strength of cores extracted from columns was found to be, on average, lower than that from beams, thus justifying the usual practice to extract cores mainly from columns, which results in a conservative approach as well as a more feasible one. Finally, some case studies were analyzed, specifically focusing on the effects of the within-storey variability. Conservative strength values, to be used especially in the case of vertical members subjected to high axial loads, are suggested.

Torsional effects due to concrete strength variability in existing buildings

2015 ◽  
Vol 8 (2) ◽  
pp. 379-399 ◽  
Author(s):  
M. De Stefano ◽  
M. Tanganelli ◽  
S. Viti
Keyword(s):  
Concrete Strength ◽  
Existing Buildings ◽  
Strength Variability

A in Vivo Assay for Standardizing Heparin Preparations

1979 ◽  
Vol 41 (03) ◽  
pp. 576-582
Author(s):  
A R Pomeroy
Keyword(s):  
In Vitro Assays ◽  
British Pharmacopoeia ◽  
In Vitro Method ◽  
Standard Preparation ◽  
Reliable Estimation ◽  
Assay Procedure ◽  
Accuracy And Precision ◽  
Heparin Preparation

SummaryThe limitations of currently used in vitro assays of heparin have demonstrated the need for an in vivo method suitable for routine use.The in vivo method which is described in this paper uses, for each heparin preparation, four groups of five mice which are injected intravenously with heparin according to a “2 and 2 dose assay” procedure. The method is relatively rapid, requiring 3 to 4 hours to test five heparin preparations against a standard preparation of heparin. Levels of accuracy and precision acceptable for the requirements of the British Pharmacopoeia are obtained by combining the results of 3 to 4 assays of a heparin preparation.The similarity of results obtained the in vivo method and the in vitro method of the British Pharmacopoeia for heparin preparations of lung and mucosal origin validates this in vivo method and, conversely, demonstrates that the in vitro method of the British Pharmacopoeia gives a reliable estimation of the in vivo activity of heparin.

GROWTH HORMONE AND RADIO-SULFATE INCORPORATION IN COSTAL CARTILAGE

1961 ◽  
Vol 37 (2) ◽  
pp. 176-182 ◽  
Author(s):  
Elliott J. Collins ◽  
Vernon F. Baker
Keyword(s):  
Growth Hormone ◽  
Costal Cartilage ◽  
Time Response ◽  
Hormone Activity ◽  
Reliable Estimation ◽  
Hypophysectomized Rats ◽  
Related Response ◽  
Sulfate Incorporation

ABSTRACT The characteristics and nature of the effect of growth hormone on the incorporation of radio-sulfate into the costal cartilage of hypophysectomized rats has been studied. The time-response studies indicate that a reliable estimation of growth hormone activity can be ascertained within a 24 hour period, and a reproducible dose-related response can be obtained at dosage levels ranging from 12-48 μg. Growth hormone stimulates the synthesis of organic sulfates and accumulation of inorganic sulfates within 48 hours.

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