Publisher Summary The chapter presents a mechanical model for the inelastic analysis of semi-rigi... more Publisher Summary The chapter presents a mechanical model for the inelastic analysis of semi-rigid and partial-strength top and seat angle bolted connections. The model is based on the same “component approach” introduced by the Eurocode 3. The proposed model maintains the Eurocode 3 approach but introduces a more refined modeling of the cleat-to-column interface, and introduces a different expression for the evaluation of the moment capacity of the joint which takes into account for the effect of the d/t (“d” is the diameter of the bolt connecting the angle to the column flange, “t” is the angle thickness), and r/t (“r” is the groove fillet radius). The proposed mechanical model is suitable to be included in existing code for the analysis of framed moment-resisting steel frames (MRSFs) including this kind of joint. The results of conducted analyses show that the model gives results that are in reasonable agreement with the experimental data and are more accurate than the results of the Eurocode 3-Annex J model.
International Journal of Microstructure and Materials Properties, 2009
A series of nondestructive tests was performed with the purpose of investigating the mechanical p... more A series of nondestructive tests was performed with the purpose of investigating the mechanical properties of the concrete employed in civil buildings. A series of specimens were prepared to correlate the in situ concrete strengths obtained by multiple combined nondestructive methods with the cubical and cylindrical strength obtained by destructive methods. The multiple combined methods (SonReb methods + Windsor Probe tests) were used for the quality control and strength estimation of the concrete. In particular, a series of specimens by aggregates having various Mohs hardness and by aggregates with only a class of Mohs hardness was prepared. The comparison between nondestructive and destructive tests, conduced on cores from the specimens, were evidenced, as the use of Windsor methods is generally justifiable only if a reliable correlation for a particular type of concrete is developed and as both the SonReb and SonReb-Win methods give resistance values that are close to the actual ones.
Geotechnical, geological and earthquake engineering, Jul 11, 2014
The correct estimation of the compressive concrete strength plays a key role in the evaluation of... more The correct estimation of the compressive concrete strength plays a key role in the evaluation of the structural performance of existing RC buildings. Both Italian (NTC 2008) and European (EC8) Standards define different levels of knowledge according to the number of tests carried out on a building. They indicate a reduced value to assume in the analysis, defined as the mean value of the compressive strength, divided by a confidence factor. However, such a procedure completely neglects the dispersion of the test data, as represented by the high values of the coefficient of variation. Instead, this aspect is treated by FEMA 356 where a limit to the coefficient of variation was introduced. In this paper, with reference to a significant number of existing buildings located in Tuscany, the coefficient of variation (cov) of concrete strength is evaluated and the frequency of high cov values is determined. The dispersion of compressive strength, obtained by SonReb method, using correlation curves calibrated ad hoc on single building, shows that increasing the number of data for each building the coefficient of variation does not necessary decrease. Moreover, the strength value considered by EC8 in the analysis for a single building, i.e. the mean value of compressive strength, is often not conservative, while the approach provided by FEMA 356 is safer since it dependent on the cov itself.
International Journal of Microstructure and Materials Properties, 2009
ABSTRACT In this paper a series of nondestructive and destructive laboratory tests is presented w... more ABSTRACT In this paper a series of nondestructive and destructive laboratory tests is presented with the purpose of investigating the influence of aggregate hardness on the test results of Windsor probe test system. A series of specimens fabricated by aggregates having various values of Mohs hardness (i.e., aggregates of fluvial origin) and by aggregates with only a class of Mohs hardness (crushed aggregates) was prepared. During the concrete casting, a series of cubical specimens was prepared. Subsequently the Windsor probe system was applied to estimate the in situ strength of specimens. Then, from each specimen two cores were extracted. Finally, a comparison between penetration tests and core strengths was carried out. The selection of the more suitable choice of Mohs hardness was carried out by neuro-fuzzy techniques. Fuzzy surfaces techniques were exploited in order to reduce the computational complexity and to select the input set of our system. The comparison between nondestructive and destructive tests, conducted on cores from the specimens, gave evidence of the reliability of the technique.
ABSTRACT When the seismic assessment of existing RC structures is conduct, a fundamental aspects ... more ABSTRACT When the seismic assessment of existing RC structures is conduct, a fundamental aspects is the assessment of in situ concrete strength; in fact, the compressive strength assessment of concrete in existing buildings is conditioned by various factors which are difficult to quantify especially when dealing with poor quality concrete.In this paper a series of destructive laboratory tests on 359 cores, extracted from specimens realized ad hoc at the Laboratory for Materials and Structures of the Mediterranean University of Reggio Calabria and from nine existing structures (buildings, viaducts, bridges and tunnels) were performed with the purpose to estimating the characteristic strength of in situ concrete. Moreover, an analytical expression was proposed in order to estimate the in situ characteristic concrete compressive strength. The results of these applications were compared with those obtained by other equations available in technical literature showing that the proposed formulation is capable of provided a good estimate of the in situ characteristic concrete compressive strength.
... materials and in the revelation of presence of metallic objects inside the same materials. ..... more ... materials and in the revelation of presence of metallic objects inside the same materials. ... besides the analysis that allow to characterize the reinforced concrete structure mechanics and to ... make some analysis that aim to determine the effective position of steel reinforcements in ...
Publisher Summary The chapter presents a mechanical model for the inelastic analysis of semi-rigi... more Publisher Summary The chapter presents a mechanical model for the inelastic analysis of semi-rigid and partial-strength top and seat angle bolted connections. The model is based on the same “component approach” introduced by the Eurocode 3. The proposed model maintains the Eurocode 3 approach but introduces a more refined modeling of the cleat-to-column interface, and introduces a different expression for the evaluation of the moment capacity of the joint which takes into account for the effect of the d/t (“d” is the diameter of the bolt connecting the angle to the column flange, “t” is the angle thickness), and r/t (“r” is the groove fillet radius). The proposed mechanical model is suitable to be included in existing code for the analysis of framed moment-resisting steel frames (MRSFs) including this kind of joint. The results of conducted analyses show that the model gives results that are in reasonable agreement with the experimental data and are more accurate than the results of the Eurocode 3-Annex J model.
International Journal of Microstructure and Materials Properties, 2009
A series of nondestructive tests was performed with the purpose of investigating the mechanical p... more A series of nondestructive tests was performed with the purpose of investigating the mechanical properties of the concrete employed in civil buildings. A series of specimens were prepared to correlate the in situ concrete strengths obtained by multiple combined nondestructive methods with the cubical and cylindrical strength obtained by destructive methods. The multiple combined methods (SonReb methods + Windsor Probe tests) were used for the quality control and strength estimation of the concrete. In particular, a series of specimens by aggregates having various Mohs hardness and by aggregates with only a class of Mohs hardness was prepared. The comparison between nondestructive and destructive tests, conduced on cores from the specimens, were evidenced, as the use of Windsor methods is generally justifiable only if a reliable correlation for a particular type of concrete is developed and as both the SonReb and SonReb-Win methods give resistance values that are close to the actual ones.
Geotechnical, geological and earthquake engineering, Jul 11, 2014
The correct estimation of the compressive concrete strength plays a key role in the evaluation of... more The correct estimation of the compressive concrete strength plays a key role in the evaluation of the structural performance of existing RC buildings. Both Italian (NTC 2008) and European (EC8) Standards define different levels of knowledge according to the number of tests carried out on a building. They indicate a reduced value to assume in the analysis, defined as the mean value of the compressive strength, divided by a confidence factor. However, such a procedure completely neglects the dispersion of the test data, as represented by the high values of the coefficient of variation. Instead, this aspect is treated by FEMA 356 where a limit to the coefficient of variation was introduced. In this paper, with reference to a significant number of existing buildings located in Tuscany, the coefficient of variation (cov) of concrete strength is evaluated and the frequency of high cov values is determined. The dispersion of compressive strength, obtained by SonReb method, using correlation curves calibrated ad hoc on single building, shows that increasing the number of data for each building the coefficient of variation does not necessary decrease. Moreover, the strength value considered by EC8 in the analysis for a single building, i.e. the mean value of compressive strength, is often not conservative, while the approach provided by FEMA 356 is safer since it dependent on the cov itself.
International Journal of Microstructure and Materials Properties, 2009
ABSTRACT In this paper a series of nondestructive and destructive laboratory tests is presented w... more ABSTRACT In this paper a series of nondestructive and destructive laboratory tests is presented with the purpose of investigating the influence of aggregate hardness on the test results of Windsor probe test system. A series of specimens fabricated by aggregates having various values of Mohs hardness (i.e., aggregates of fluvial origin) and by aggregates with only a class of Mohs hardness (crushed aggregates) was prepared. During the concrete casting, a series of cubical specimens was prepared. Subsequently the Windsor probe system was applied to estimate the in situ strength of specimens. Then, from each specimen two cores were extracted. Finally, a comparison between penetration tests and core strengths was carried out. The selection of the more suitable choice of Mohs hardness was carried out by neuro-fuzzy techniques. Fuzzy surfaces techniques were exploited in order to reduce the computational complexity and to select the input set of our system. The comparison between nondestructive and destructive tests, conducted on cores from the specimens, gave evidence of the reliability of the technique.
ABSTRACT When the seismic assessment of existing RC structures is conduct, a fundamental aspects ... more ABSTRACT When the seismic assessment of existing RC structures is conduct, a fundamental aspects is the assessment of in situ concrete strength; in fact, the compressive strength assessment of concrete in existing buildings is conditioned by various factors which are difficult to quantify especially when dealing with poor quality concrete.In this paper a series of destructive laboratory tests on 359 cores, extracted from specimens realized ad hoc at the Laboratory for Materials and Structures of the Mediterranean University of Reggio Calabria and from nine existing structures (buildings, viaducts, bridges and tunnels) were performed with the purpose to estimating the characteristic strength of in situ concrete. Moreover, an analytical expression was proposed in order to estimate the in situ characteristic concrete compressive strength. The results of these applications were compared with those obtained by other equations available in technical literature showing that the proposed formulation is capable of provided a good estimate of the in situ characteristic concrete compressive strength.
... materials and in the revelation of presence of metallic objects inside the same materials. ..... more ... materials and in the revelation of presence of metallic objects inside the same materials. ... besides the analysis that allow to characterize the reinforced concrete structure mechanics and to ... make some analysis that aim to determine the effective position of steel reinforcements in ...
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