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.

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.

scholarly journals Simplified Seismic Vulnerability Assessment Methods: A Comparative Analysis with Reference to Regional School Building Stock in Italy

2020 ◽  
Vol 10 (19) ◽  
pp. 6771
Author(s):  
F. Ceroni ◽  
N. Caterino ◽  
A. Vuoto
Keyword(s):  
Large Scale ◽  
Seismic Vulnerability ◽  
Computational Effort ◽  
School Buildings ◽  
Existing Buildings ◽  
Building Stock ◽  
Output Data ◽  
Seismic Vulnerability Assessment ◽  
Data Limitations ◽  
Available Information

The paper compares several simplified methods proposed in the literature for assessing the seismic vulnerability of existing buildings. Type and number of input and output data, limitations of use for different structural typologies, and complexity of use are examined for each methodology to identify the most suitable for assessing the vulnerability of a given class of buildings, based on the available data, the computational effort, and the type of vulnerability judgment. The selected methods were applied to a sample of school buildings located in the province of Naples (Italy). Data were available due to a digital platform and were used to verify the possibility of providing reliable large scale vulnerability judgments based on a reduced set of information, without carrying out additional surveys. The most simplified methods were applied to a sample of about a thousand of buildings, while more detailed methods, needing more information, were applied to a smaller sample. The comparison between the results obtained from different methods allows highlighting advantages and weaknesses of each, so as to identify the convenience in their use according to the specific available information and the objectives of the analysis, finally to evaluate which is more or less safe.

Seismic Vulnerability Assessment Using the Instrumentation of an Existing Building

2011 ◽  
Vol 482 ◽  
pp. 79-87 ◽  
Author(s):  
Fabien Duco ◽  
Jean Pierre Faye ◽  
Serge Caperaa ◽  
Eric Reubrez
Keyword(s):  
Vulnerability Assessment ◽  
Large Scale ◽  
Seismic Vulnerability ◽  
Modal Identification ◽  
Ambient Vibration ◽  
Elastic Behaviour ◽  
Existing Buildings ◽  
Engineering Structures ◽  
Seismic Vulnerability Assessment ◽  
Damage Level

France is a country composed of moderate seismic hazard regions but however vulnerable to earthquakes. Indeed, only a few parts of existing buildings have been built using paraseismic regulation. Several current large-scale seismic vulnerability assessment methods are used, as Hazus or Risk-UE, but they are inappropriate to the analysis of a specific building. In our case, we use an experimental approach to study the elastic behaviour of existing buildings: ambient vibration analyses seem to be an interesting way to determine the vulnerability. Ambient noise testing with Output-Only Modal Identification is a low-cost non-destructive method to provide vibration data from civil engineering structures like buildings. The interest of this method is to obtain dynamic parameters with only natural excitations: wind, traffic, human activity... In the frame of the “Plan séisme des Hautes-Pyrénées”, the building considered is the relatively regular 18-storey Ophite Tower located in Lourdes, France. The vibration measurements are conducted using a 24-channel system connected to an acquisition station. The modal parameters of this building (natural frequencies, modal shapes and damping) are calculated using the stochastic subspace identification method. These parameters, extracted from in situ data, are then used to calibrate a model. Having defined damage level criterion, the response motion, produced by seismic events, will lead to the determination of the vulnerability curves of Ophite Tower.

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

Concrete Strength and Deformation Property under Sea Water Erosion Environment

2012 ◽  
Vol 446-449 ◽  
pp. 2554-2559 ◽  
Author(s):  
Jian Jun Cai ◽  
Feng Zhang ◽  
Wei Cui ◽  
Shou Shan Chen ◽  
Pu Lun Liu
Keyword(s):  
Large Scale ◽  
Failure Modes ◽  
Deformation Property ◽  
Sea Water ◽  
Dynamic Stiffness ◽  
Concrete Strength ◽  
Strain Curve ◽  
Water Erosion ◽  
Strength And Deformation ◽  
Erosion Environment

In order to effectively assess the concrete strength and deformation property under sea water erosion environment, concrete stress and strain curve was researched with the number of wet and dry cycle of 0 times, 10 times , 20 times, 30 times, 40 times, 50 times and 60 times based on the large-scale static and dynamic stiffness servo test set. The stress - strain curves of concrete was tested for the lateral pressure 10.8MPa, 14.4MPa, and 18.8MPa at different dry-wet cycles, The failure modes and superficial cracking characteristics of specimens are reported at different dry-wet cycles. Concrete elastic modulus and compressive strength were researched. Based on concrete mechanical theory , the classic Kufer-Gerstle strength criteria of concrete was used, a large number of test samples of multivariate data were nonlinear regressed, a biaxial concrete strength criterion was established taking into account the stress ratio and the number of dry-wet cycles.

An Empirical Method to Assess the Seismic Vulnerability of Existing Buildings Using the HVSR Technique

2001 ◽  
Vol 158 (12) ◽  
pp. 2635-2647 ◽  
Author(s):  
M. Mucciarelli ◽  
P. Contri ◽  
G. Monachesi ◽  
G. Calvano ◽  
M. Gallipoli
Keyword(s):  
Seismic Vulnerability ◽  
Empirical Method ◽  
Existing Buildings ◽  
Hvsr Technique

scholarly journals Pounding Effects on the Earthquake Response of Adjacent Reinforced Concrete Structures Strengthened by Cable Elements

2014 ◽  
Vol 44 (2) ◽  
pp. 41-56 ◽  
Author(s):  
Angelos Liolios ◽  
Asterios Liolios ◽  
George Hatzigeorgiou ◽  
Stefan Radev
Keyword(s):  
Reinforced Concrete ◽  
Numerical Approach ◽  
Earthquake Response ◽  
Existing Buildings ◽  
The Finite Element Method ◽  
Time Step ◽  
Engineering Structures ◽  
Rc Structures ◽  
Incremental Approach ◽  
Rc Frames

Abstract A numerical approach for estimating the effects of pounding (seismic interaction) on the response of adjacent Civil Engineering structures is presented. Emphasis is given to reinforced concrete (RC) frames of existing buildings which are seismically strengthened by cable-elements. A double discretization, in space by the Finite Element Method and in time by a direct incremental approach is used. The unilateral behaviours of both, the cable-elements and the interfaces contact-constraints, are taken strictly into account and result to inequality constitutive conditions. So, in each time-step, a non-convex linear complementarity problem is solved. It is found that pounding and cable strengthening have significant effects on the earthquake response and, hence, on the seismic upgrading of existing adjacent RC structures.

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