Download or read book Assessment of Concrete Strength in Existing Structures Using Nondestructive Tests and Cores written by Maitham Fadhil Abbas Alwash and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: To assess concrete strength in an existing structure, the current methodology combines nondestructive measurements (NDT) like rebound hammer or/and pulse velocity with destructive technique (cores) in order to implement a relationship ''conversion model” between the compressive strength and NDT measurements. The conversion model is used to estimate the local strength value at each test location using the corresponding NDT value.Then the estimated mean strength and/or estimated strength standard deviation (concrete strength variability) values are calculated. However, the reliability of these estimated values isalways a questionable issue because of the uncertainties associated with the strength assessment based upon NDT measurements. To improve the reliability, the uncertainties must be reduced by specifying and controlling their influencing factors. Therefore, the objective of this thesis is to analyze the current assessment methodology in order to provide practical recommendations that can improve the reliability of assessing the in-situ strength in existing concrete structures by nondestructive tests and cores.To this end, a simulator was built in order to analyze the effects of the most influencing factors using a large campaign of datasets from different sources (in-situ or laboratory studies,and generated synthetic data).The first contribution of this work is the development of a new model identification approach“bi-objective” that can efficiently capture the strength variability in addition to the mean strength. After studying the effect of the way of selection the core locations, a method was proposed to select these locations depending on the NDT measurements “conditional selection” that improves the quality of assessment without additional cost. A third innovation was the development of a procedure to identify the relation between the number of cores and the accuracy of the estimation. Finally recommendations were derived in order to providemore reliable estimated values.
Download or read book Guide to Assessment of Concrete Strength in Existing Structures written by British Standards Institute Staff and published by . This book was released on 1981-11-30 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: Concretes, Cement and concrete technology, Strength of materials, Mechanical testing, In situ, Field testing, Structural members, Test specimens, Cubic shape, Structural design, Ultrasonic testing, Fracture, Surface properties, Hardness testing, Compressive strength, Compression testing
Download or read book Assessment of Concrete Strength in Existing Structures written by F. Michael Bartlett and published by Department of Civil Engineering, University of Alberta. This book was released on 1994 with total page 297 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Guide to Assessment of Concrete Strength in Existing Structures written by British Standards Institution and published by . This book was released on 1981 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Strength Evaluation of Existing Concrete Buildings written by American Concrete Institute and published by . This book was released on 2003 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Testing of Concrete in Structures written by J. H. Bungey and published by Chapman & Hall. This book was released on 1982 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Monitoring and Safety Evaluation of Existing Concrete Structures written by fib Fédération internationale du béton and published by fib Fédération internationale du béton. This book was released on 2003 with total page 316 pages. Available in PDF, EPUB and Kindle. Book excerpt: The condition assessment of aged structures is becoming a more and more important issue for civil infrastructure management systems. The continued use of existing systems is, due to environmental, economical and socio-political assets, of great significance and is growing larger every year. Thus the extent of necessary repair of damaged reinforced concrete structures is of major concern in most countries today. Monitoring techniques may have a decisive input to limit expenditures for maintenance and repair of existing structures. Modern test and measurement methods as well as computational mechanics open the door for a wide variety of monitoring applications. The need for quantitative and qualitative knowledge has led to the development and improvement of surveillance techniques, which have already found successful application in other disciplines such as medicine, physics and chemistry. The design of experimental test and measurement systems is inherently an interdisciplinary activity. The specification of the instrumentation to measure the structural response will involve the skills of civil, electrical and computer engineers. The main aim of fib Commission 5, Structural servicer life aspects, is to provide a rational procedure to obtain an optimal technical-economic performance of concrete structures in service and to ensure a feedback of experience gained to design, execution, maintenance and rehabilitation. Against this background fib Task Group 5.1 Monitoring and Safety Evaluation of Existing Concrete Structures had been established to evaluate the existing practice worldwide. The objective of this state-of-art report is to summarize the most important inspection and measuring methods, to describe the working process and to evaluate the applicability to structural monitoring. Particular emphasis is placed upon non-destructive systems, lifetime monitoring, data evaluation and safety aspects.
Download or read book De usu librorum apocryphorum V T in N Testamento written by and published by . This book was released on with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Partial factor methods for existing concrete structures written by FIB - Féd. Int. du Béton and published by FIB - Féd. Int. du Béton. This book was released on 2016 with total page 145 pages. Available in PDF, EPUB and Kindle. Book excerpt: For a large part of the existing buildings and infrastructure the design life has been reached or will be reached in the near future. These structures might need to be reassessed in order to investigate whether the safety requirements are met. Current practice on the assessment of existing concrete structures however needs a thorough evaluation from a risk and reliability point of view, as they are mostly verified using simplified procedures based on the partial factor method commonly applied in design of new structures. Such assessments are often conservative and may lead to expensive upgrades. Although the last decades reliability-based assessment of existing concrete structures has gained wide attention in the research field, a consistent reliability-based assessment framework and a practically applicable codified approach which is compatible with the Eurocodes and accessible for common structural engineering problems in everyday practice is currently missing. Such an approach however allows for a more uniform, more objective and probably more widely applied assessment approach for existing concrete structures. Hence, in this bulletin two different partial factor formats are elaborated, i.e. the Design Value Method (DVM) and the Adjusted Partial Factor Method (APFM), enabling the incorporation of specific reliability related aspects for existing structures. The DVM proposes a fundamental basis for evaluating partial factors whereas the APFM provides adjustment factors to be applied on the partial factors for new structures in EN 1990. In this bulletin both methods are elaborated and evaluated and a basis is provided for decision making regarding the target safety level of existing structures.
Download or read book Safety and performance concept Reliability assessment of concrete structures written by fib Fédération internationale du béton and published by FIB - Féd. Int. du Béton. This book was released on 2018-08-01 with total page 375 pages. Available in PDF, EPUB and Kindle. Book excerpt: Concrete structures have been built for more than 100 years. At first, reinforced concrete was used for buildings and bridges, even for those with large spans. Lack of methods for structural analysis led to conservative and reliable design. Application of prestressed concrete started in the 40s and strongly developed in the 60s. The spans of bridges and other structures like halls, industrial structures, stands, etc. grew significantly larger. At that time, the knowledge of material behaviour, durability and overall structural performance was substantially less developed than it is today. In many countries statically determined systems with a fragile behavior were designed for cast in situ as well as precast structures. Lack of redundancy resulted in a low level of robustness in structural systems. In addition, the technical level of individual technologies (e.g. grouting of prestressed cables) was lower than it is today. The number of concrete structures, including prestressed ones, is extremely high. Over time and with increased loading, the necessity of maintaining safety and performance parameters is impossible without careful maintenance, smaller interventions, strengthening and even larger reconstructions. Although some claim that unsatisfactory structures should be replaced by new ones, it is often impossible, as authorities, in general, have only limited resources. Most structures have to remain in service, probably even longer than initially expected. In order to keep the existing concrete structures in an acceptable condition, the development of methods for monitoring, inspection and assessment, structural identification, nonlinear analysis, life cycle evaluation and safety and prediction of the future behaviour, etc. is necessary. The scatter of individual input parameters must be considered as a whole. This requires probabilistic approaches to individual partial problems and to the overall analysis. The members of the fib Task Group 2.8 “Safety and performance concepts” wrote, on the basis of the actual knowledge and experience, a comprehensive document that provides crucial knowledge for existing structures, which is also applicable to new structures. This guide to good practice is divided into 10 basic chapters dealing with individual issues that are critical for activities associated with preferably existing concrete structures. Bulletin 86 starts with the specification of the performance-based requirements during the entire lifecycle. The risk issues are described in chapter two. An extensive part is devoted to structural reliability, including practical engineering approaches and reliability assessment of existing structures. Safety concepts for design consider the lifetime of structures and summarise safety formats from simple partial safety factors to develop approaches suitable for application in sophisticated, probabilistic, non-linear analyses. Testing for design and the determination of design values from the tests is an extremely important issue. This is especially true for the evaluation of existing structures. Inspection and monitoring of existing structures are essential for maintenance, for the prediction of remaining service life and for the planning of interventions. Chapter nine presents probabilistically-based models for material degradation processes. Finally, case studies are presented in chapter ten. The results of the concrete structures monitoring as well as their application for assessment and prediction of their future behaviour are shown. The risk analysis of highway bridges was based on extensive monitoring and numerical evaluation programs. Case studies perfectly illustrate the application of the methods presented in the Bulletin. The information provided in this guide is very useful for practitioners and scientists. It provides the reader with general procedures, from the specification of requirements, monitoring, assessment to the prediction of the structures’ lifecycles. However, one must have a sufficiently large amount of experimental and other data (e.g. construction experience) in order to use these methods correctly. This data finally allows for a statistical evaluation. As it is shown in case studies, extensive monitoring programs are necessary. The publication of this guide and other documents developed within the fib will hopefully help convince the authorities responsible for safe and fluent traffic on bridges and other structures that the costs spent in monitoring are first rather small, and second, they will repay in the form of a serious assessment providing necessary information for decision about maintenance and future of important structures.
Download or read book Non Destructive In Situ Strength Assessment of Concrete written by Denys Breysse and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book presents the work of the RILEM Technical Committee 249-ISC. Addressing the effective application of new recommendations for non-destructive in situ strength assessment of concrete, it provides information about the different steps of the investigation and processing of test results, until the delivery of strength estimates, and includes tables giving the minimum required number of cores in a variety of situations as well as several examples of how the recommendations can be used in practice. The book explores a topic which is of major importance, i.e. the assessment of concrete compressive strength in existing structures. This property (both mean and standard deviation) is a key input in many cases, such as the reinforcement of structures, the safety checking, the extension of service life. As the new RILEM recommendations imply a deep revision (and improvement) of field practice, the book is intended for managers of structures, structural engineers and specialists of NDT that have to answer these issues. More widely, it will benefit engineers and students who are interested in NDT and in the safety analysis of structures.
Download or read book Handbook on Nondestructive Testing of Concrete written by V. M. Malhotra and published by CRC Press. This book was released on 2004 with total page 389 pages. Available in PDF, EPUB and Kindle. Book excerpt: Civil engineers will value this resource that examines the tools and techniques used to estimate the in-place strength on concrete, permeation properties that relate to potential durability, and the methods used to assess the internal condition of concrete and the corrosion activity of steel reinforcement.
Download or read book The Life of Structures written by G.S.T Armer and published by Elsevier. This book was released on 2013-10-22 with total page 469 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Life of Structures: Physical Testing covers the proceedings of a seminar of the same name. The said seminar is focused on the actions on structures and the performance of existing populations of structures; the properties and performance of building materials; and the internal and external environments of buildings. The book covers topics such as the methodology for the prediction of the life of existing structures; reliability of service-proven structural systems; and some effects of micro-environment on materials. Also covered are subjects such as the assessment of structures through field measured dynamic response; physical properties of structures investigated by dynamic methods; and the stiffness damage test. The text is recommended for engineers who would like to know more about the strength and lifespan of structures, as well as the effectivity of the materials involved in their construction.
Download or read book Strength Evaluation of Existing Concrete Buildings written by ACI Committee 437--Strength Evaluation of Existing Concrete Structures and published by . This book was released on 1997 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Guide for Evaluation of Concrete Structures Prior to Rehabilitation written by ACI Committee 364 and published by . This book was released on 1993 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Strength and Related Properties of Concrete written by Sándor Popovics and published by John Wiley & Sons. This book was released on 1998-03-23 with total page 558 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work discusses the variations that occur in the strength of concrete and presents numerical methods useful in interpreting these variations. Individual chapters include the relationship between composition and strength of concrete.
Download or read book Strengthening and Retrofitting of Existing Structures written by Aníbal Costa and published by Springer. This book was released on 2017-10-13 with total page 339 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the fundamentals of strengthening and retrofitting approaches, solutions and technologies for existing structures. It addresses in detail specific techniques for the strengthening of traditional constructions, reinforced concrete buildings, bridges and their foundations. Finally, it discusses issues related to standards and economic decision support tools for retrofitting.
