Determining the in situ concrete strength of existing structures for assessing their structural safety

2012 ◽  
Vol 13 (1) ◽  
pp. 27-31 ◽  
Author(s):  
R.D.J.M. Steenbergen ◽  
A.H.J.M. Vervuurt
Keyword(s):  
Concrete Strength ◽  
Structural Safety ◽  
Existing Structures

scholarly journals The Structural Diagnosis of Existing RC Buildings: The Role of Nondestructive Tests in the Case of Low Concrete Strength

2020 ◽  
Vol 5 (11) ◽  
pp. 100
Author(s):  
Silvia Santini ◽  
Angelo Forte ◽  
Lorena Sguerri
Keyword(s):  
Mechanical Properties ◽  
Concrete Strength ◽  
High Strength ◽  
Ultrasonic Pulse ◽  
Assessment Process ◽  
Structural Safety ◽  
Existing Structures ◽  
Nondestructive Tests ◽  
Compression Properties ◽  
Pull Out

In the structural safety assessment process of existing structures, knowledge of the mechanical properties of the materials is key. Different experimental activities carried out on materials extracted from existing reinforced concrete buildings show a high strength variability, especially concrete. In the past, the lack of standardized quality control for materials and workmanship caused nonuniform and homogeneous properties within the same structure. The most accurate and reliable experimental technique consists of performing direct tests on the materials, but these are considerably expensive and invasive. In this paper, alternative indirect methods that estimate material properties by correlating different physical measures were proved to reduce invasive inspections on existing buildings and infrastructures, especially in built heritage. A complete experimental activity concerning destructive and nondestructive tests was conducted on elements (four portions of a column and a beam portion) removed from an Italian school building built in 1940. Destructive and nondestructive methods were compared and appropriate correlation laws developed to predict the main mechanical properties of the studied material. Reliable correlations were identified considering the pull-out test, Sonic–Rebound (SonReb) combined method and ultrasonic pulse velocities (UPVs). The latter were mapped by tomography, which highlighted the compression properties of concrete in the different structural sections.

A Review of Experimental Results about In Situ Concrete Strength

2013 ◽  
Vol 773 ◽  
pp. 278-282 ◽  
Author(s):  
Marco Vona
Keyword(s):  
Concrete Strength ◽  
Ultrasonic Pulse ◽  
Experimental Results ◽  
Alternative Procedure ◽  
Existing Structures ◽  
Experimental Campaign ◽  
Rebound Number ◽  
Planning Strategies ◽  
Non Destructive

In this paper, experimental results on the in situ concrete strength have been reported in order to suggest some possible improvements of the current investigation planning strategies. The results of experimental campaign carried out on existing structures are discussed in order to investigate the variability of Destructive Tests (DTs) and Non Destructive Tests (NDTs). Then, the characteristics of the most usual procedures (core testing, rebound number, ultrasonic pulse, ...) have been examined. The results showed primarily the unsuitability (thus its uselessness) of the rebound test in order to describe the variability of concrete characteristics inside the buildings. On this basis, an alternative procedure has been suggested to obtain in-situ concrete strength.

Adaptive Estimation of the In Situ Characteristic Concrete Strength

2019 ◽  
Vol 292 ◽  
pp. 257-263
Author(s):  
Stanislav S. Derechennik ◽  
Viktar V. Tur
Keyword(s):  
Confidence Level ◽  
Adaptive Estimation ◽  
Concrete Strength ◽  
Test Results ◽  
Limited Sample ◽  
Limited Sample Size ◽  
Existing Structures ◽  
Main Representative ◽  
Partial Factor

For calculation of existing concrete structures on the basis of the partial factor format, the main representative value is the actual in-situ characteristic value of the concrete strength. When samples are tested, the concrete in-situ strength of the structure shall be determined, statistically if possible, from the test results. In accordance with EN 1990 the 5% percentile value is calculated on the basis of a unilaterally limited constant confidence level. It was found the in some case, estimation of the in-situ characteristic concrete strength taking a constant confidence level does not allow to adequately assess the reliability of the existing structures. A new estimator based on non-parametric statistical method was proposed for estimating of the in-situ characteristic concrete strength with a given arbitrary confidence level. The procedure that was proposed allows one to re-establish of the estimator pdf even with a very limited sample size. It is established, that the choice of the confidence level of the estimator should be based on the average reliability of the structure.

Value of information of in situ inspections of mooring lines

2021 ◽  
pp. 1748006X2098740
Author(s):  
Jorge Mendoza ◽  
Jacopo Paglia ◽  
Jo Eidsvik ◽  
Jochen Köhler
Keyword(s):  
Pitting Corrosion ◽  
Value Of Information ◽  
Structural Reliability ◽  
Structural Safety ◽  
Statistical Dependence ◽  
Mooring System ◽  
Mooring Lines ◽  
Corrosion Condition ◽  
Chain Links

Mooring systems that are used to secure position keeping of floating offshore oil and gas facilities are subject to deterioration processes, such as pitting corrosion and fatigue crack growth. Past investigations show that pitting corrosion has a significant effect on reducing the fatigue resistance of mooring chain links. In situ inspections are essential to monitor the development of the corrosion condition of the components of mooring systems and ensure sufficient structural safety. Unfortunately, offshore inspection campaigns require large financial commitments. As a consequence, inspecting all structural components is unfeasible. This article proposes to use value of information analysis to rank identified inspection alternatives. A Bayesian Network is proposed to model the statistical dependence of the corrosion deterioration among chain links at different locations of the mooring system. This is used to efficiently update the estimation of the corrosion condition of the complete mooring system given evidence from local observations and to reassess the structural reliability of the system. A case study is presented to illustrate the application of the framework.

Failure by corrosion in PC bridges: a case history of a viaduct in Italy

2016 ◽  
Vol 7 (2) ◽  
Author(s):  
Piero Colajanni ◽  
Antonino Recupero ◽  
Giuseppe Ricciardi ◽  
Nino Spinella
Keyword(s):  
Prestressed Concrete ◽  
Design Methodology ◽  
Progressive Collapse ◽  
Numerical Analyses ◽  
Existing Structures ◽  
History Of ◽  
Progressive Collapse Analysis ◽  
Practical Implications ◽  
Post Tensioned

Purpose The paper illustrates a viaduct collapse due to corrosion phenomena. Moreover, a contribution to the issues related to both the control of existing structures and design methods to be followed for the construction of new buildings is provided. Design/methodology/approach The objectives were achieved by in situ observations and numerical analyses. The effects of corrosion phenomena are investigated, and the progressive collapse analysis is provided to be helpful in this case. Findings The damages induced by corrosion phenomena have caused the collapse of the viaduct taken in to account. The performed numerical analyses were able to reproduce the effects of corrosion in terms of reduction of wires diameter. Research limitations/implications The research is limited to prestressed concrete viaduct with post-tensioned cables. Practical implications A monitoring plan, subdivided in several phases, is suggested, to avoid critical situations as these described. Originality/value The case study brought useful information on the effects of corrosion on the decks section, showing how the technology in post-tensioned cables is usually insidious and prone to the issues relating to corrosion of the wires

scholarly journals Fatigue lifetime of a RC bridge along the Carajás railroad

2012 ◽  
Vol 5 (5) ◽  
pp. 627-658
Author(s):  
R. R. F. Santos ◽  
D. R. C. Oliveira
Keyword(s):  
Reinforced Concrete ◽  
Laboratory Tests ◽  
Structural Safety ◽  
Structural Behavior ◽  
Concrete Bridge ◽  
Structural Elements ◽  
Fatigue Lifetime ◽  
Reinforced Concrete Bridge ◽  
Bridge Number

The aim of this paper is to present and discuss the results obtained with a methodology used to characterize the concrete and to evaluate the structural safety against fatigue of the reinforced concrete bridge number 50A located in the Carajás railroad. An "in situ" inspection was carried out in order to assess the evolution of damage in structural elements, with reference to information available in existing projects, calculation memory and reporting of previous inspections. Extractions of concrete testimonies, alkalinity tests, sclerometry, pacometry and laboratory tests were also performed to characterize the materials mechanically and estimate the structural behavior of the bridge under higher future loads.

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