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Book Analysis of Diagonally Cracked Conventionally Reinforced Concrete Girders in the Service Load Range

Download or read book Analysis of Diagonally Cracked Conventionally Reinforced Concrete Girders in the Service Load Range written by Melissa J. Robelo and published by . This book was released on 2004 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: Performance evaluation of conventionally reinforced concrete (CRC) bridge superstructure elements with diagonal cracks is of interest to the bridge engineering community. Standardized methods to predict service-level stress magnitudes in cracked bridge girders under combined bending and shear forces are not available. An analysis procedure was developed to determine the response of CRC bridge girders with existing diagonal cracks. The method estimates the stirrup stress range without prior knowledge of the previous stirrup strain history. Modified Compression Field Theory (MCFT), a sectional analysis procedure, is used in the current specifications to predict capacity of CRC and prestressed concrete beams and relies on equilibrium and compatibility conditions based on an initial uncracked section. In this research, the method was used to predict service-level performance for cracked sections. Effective response prediction of a previously cracked beam was achieved through alteration of the constitutive relationships to permit softening behavior of the concrete to begin much earlier in the loading history. Validation of the procedure was performed through comparison of analytically predicted stirrup strains with those from full-size laboratory specimens. Empirical data were found to correspond well with the predicted responses. The cracked section analysis procedure was then utilized to estimate the potential for low-cycle fatigue damage of an in-service bridge. A moment and shear interaction surface corresponding to stirrup yielding was estimated and compared with the load effects produced from a data set of over 14,000 permitted trucks to estimate the anticipated life of the bridge based on low-cycle fatigue damage.

Book Transactions of the American Society of Civil Engineers

Download or read book Transactions of the American Society of Civil Engineers written by American Society of Civil Engineers and published by . This book was released on 2006 with total page 1264 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vols. 29-30 contain papers of the International Engineering Congress, Chicago, 1893; v. 54, pts. A-F, papers of the International Engineering Congress, St. Louis, 1904.

Book Development of Acoustic Emissions Testing Procedures Applicable to Conventionally Reinforced Concrete Deck Girder Bridges Subjected to Diagonal Tension Cracking

Download or read book Development of Acoustic Emissions Testing Procedures Applicable to Conventionally Reinforced Concrete Deck Girder Bridges Subjected to Diagonal Tension Cracking written by Steven C. Lovejoy and published by . This book was released on 2006 with total page 1068 pages. Available in PDF, EPUB and Kindle. Book excerpt: A need exists to develop a non-destructive testing technique that can identify the formation and propagation of diagonal tension cracks in conventionally steel reinforced concrete deck girder (RCDG) highway bridges in the State of Oregon. Such a technique could be included into a structural health monitoring (SHM) system installed on specific bridges to automatically monitor the current state of structural damage in primary load supporting elements and provide notification of recent damage to bridge engineers in nearly real time. This research investigates the practical application of AE used to supplement a conventional SHM on vintage RCDG bridges. Background work presented in the Appendices investigates stress wave propagation in non-reinforced and steel reinforced concrete media. Based on the characterization of stress wave speeds, amplitude attenuation, frequency content and wave forms found in concrete media, testing methods are developed and applied to 31 full sized RCDG test specimens that include variations in loading, load capacity and structural detailing. Several different AE test procedures are used to characterize the damage states of the test beams as they are progressively loaded to failure. Four previously developed AE parameters that characterize both damage progression and damage state are applied which include the Felicity and Calm Ratios, Severity and the Historic Index. Both Felicity and Calm Ratios were found to respond to the damage state of the test beam as determined from more conventional assessment methods such as crack width and load. For the practical in-service loading ranges of 20 to 80% of ultimate capacity both the Felicity and Calm Ratios were found to respond in a nearly linear manner with increasing damage. Three categories of damage state are defined which are based on the ODOT crack comparator tool which is used for in-service maintenance inspections of these bridges. Felicity and Calm Ratio values are related to these damage states for the specific type of bridge girders being tested and can be used to estimate in-service damage states. The Severity and Historic Index responses were found to be an effective means of identifying the formation and extension of diagonal tension cracks as they developed. Threshold levels for these two parameters are identified for specific AE sensor types when applied to this class of bridge girder. A preliminary set of AE testing and analysis procedures were developed that were applied to three in-service bridges. These bridge tests used both controlled and ambient loading protocols. The structural response to each load case was quantified by using both crack width motion and reinforcing steel strain range. These structural parameters were correlated with the AE data. The Calm Ratio was found to be of practical importance and that the values recorded were in reasonably good agreement with the laboratory data once the imposed loads and current crack widths were considered. The Severity and Historic Index were also found to be of practical importance to bridge testing and structural health monitoring as they were found to be very sensitive to increasing damage, yet exhibit good stability provided enough AE activity was present. A recommend set of guidelines and practices for applying AE to vintage RCDG bridges is developed and presented.

Book Influence of Diagonal Cracks on Negative Moment Flexural Anchorage Performance in Reinforced Concrete Bridge Girders

Download or read book Influence of Diagonal Cracks on Negative Moment Flexural Anchorage Performance in Reinforced Concrete Bridge Girders written by Joshua K. Goodall and published by . This book was released on 2010 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt: Large numbers of vintage reinforced concrete deck-girder bridges remain in the national bridge inventory. Many of these exhibit diagonal cracking and other distress. Due to the design practices of the time, it is common to observe cracks at locations where flexural reinforcing steel is terminated along the span. The presence of diagonal cracking increases the demand in the flexural steel and some details may be susceptible to anchorage failure. Recent developments in load rating using Load and Resistance Factor Rating (LRFR), which incorporates Modified Compression Field Theory (MCFT), require a check of the flexural steel in the presence of shear. This practice has resulted in tensile anchorage or flexural capacity checks controlling some load ratings. Previous tests performed by OSU indicate that failure for many girders exhibiting steep initial diagonal cracking is eventually controlled by shear-moment interaction which evolves into a much more shallow crack at failure. It is hypothesized that this is due to an underestimation of the bond stress in developing bars. To test this hypothesis, four full-scale tests were performed on specimens with a pre-cast crack and cutoff tensile bars. These tests indicate that the bond stress in the developed bars is greater than that predicted by current specifications. Failure behavior and subsequent load-induced cracking of each specimen was found to be independent of the initial diagonal cracking. Analysis indicates that current code procedures are sufficient to predict failure modes. However this must be done using a more appropriate estimate of bond stress.

Book Shear Repair Methods for Conventionally Reinforced Concrete Girders and Deep Beams

Download or read book Shear Repair Methods for Conventionally Reinforced Concrete Girders and Deep Beams written by Daniel A. Howell and published by . This book was released on 2009 with total page 816 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many conventionally reinforced concrete deck girder bridges (RCDG) and their intermediate supporting bent caps were designed during the Eisenhower interstate era of the 1950's with the AASHO design equations at the time, which subsequently place higher demand on the concrete. The referenced components may exhibit diagonal cracking due to the initial design assumptions, increased traffic volume and truck weights, as well as temperature and shrinkage affects. Action is needed as these structures approach the end of their useful design life. Wholesale replacement is not economically feasible; therefore, repair may provide a more attractive alternative to maintain operational safety and freight mobility. The current research program builds on previous work at OSU, which focused on estimating unrepaired specimen capacity, to include various repair methods. The experimental program included full scale testing of specimens with vintage 1950s details, reinforcing steel, concrete strength/composition, and flexural cutoffs details. Repairs included externally applied steel stirrups, supplemental internal stirrups, externally applied carbon fiber reinforced plastic (CFRP), carbon fiber tape utilized in a near surface mount application, and longitudinal post tensioning (bent cap specimen only). All specimens were initially loaded under quasi-static force control to produce diagonal cracks in the specimen then repaired and tested to failure. Ultimate specimen capacity was compared against that predicted from those available in the literature (where applicable), international codes, sectional Modified Compression Field Theory (MCFT) analysis, Modified Zararis Mechanical Model (bent caps only), Strut-and-Tie methods (bent cap only), and nonlinear finite element analysis (NLFEM). Results indicate the repair methods increased the member strength and the predicted member strenths compare well to certain international codes, sectional MCFT analysis, and nonlinear FEM element analysis. Some repair techniques such as surface mounted CFRP produced disparate outcomes for different specimen types. The NSM repair technique requires additional research to draw general conclusions. Longitudinal post tensioning compared well with the Modified Zararis method. STM methods form a very conservative lower bound for design and are thus not suggested for base specimen capacity prediction in a retrofit analysis. Design recommendations for the deep beams are not provided, as there is not sufficient data to support general conclusions.

Book Dissertation Abstracts International

Download or read book Dissertation Abstracts International written by and published by . This book was released on 2009 with total page 810 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Proceedings

Download or read book Proceedings written by and published by . This book was released on 1979 with total page 690 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Society of Petroleum Engineers Journal

Download or read book Society of Petroleum Engineers Journal written by Society of Petroleum Engineers of AIME. and published by . This book was released on 1980 with total page 646 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Fatigue Testing and Analysis

Download or read book Fatigue Testing and Analysis written by Yung-Li Lee and published by Elsevier. This book was released on 2011-04-18 with total page 417 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fatigue Testing and Analysis: Theory and Practice presents the latest, proven techniques for fatigue data acquisition, data analysis, and test planning and practice. More specifically, it covers the most comprehensive methods to capture the component load, to characterize the scatter of product fatigue resistance and loading, to perform the fatigue damage assessment of a product, and to develop an accelerated life test plan for reliability target demonstration. This book is most useful for test and design engineers in the ground vehicle industry. Fatigue Testing and Analysis introduces the methods to account for variability of loads and statistical fatigue properties that are useful for further probabilistic fatigue analysis. The text incorporates and demonstrates approaches that account for randomness of loading and materials, and covers the applications and demonstrations of both linear and double-linear damage rules. The reader will benefit from summaries of load transducer designs and data acquisition techniques, applications of both linear and non-linear damage rules and methods, and techniques to determine the statistical fatigue properties for the nominal stress-life and the local strain-life methods. - Covers the useful techniques for component load measurement and data acquisition, fatigue properties determination, fatigue analysis, and accelerated life test criteria development, and, most importantly, test plans for reliability demonstrations - Written from a practical point of view, based on the authors' industrial and academic experience in automotive engineering design - Extensive practical examples are used to illustrate the main concepts in all chapters

Book Engineering and Design

Download or read book Engineering and Design written by Us Army Corps Of Engineers and published by Military Bookshop. This book was released on 1995-06 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt: This manual provides guidance on evaluating the condition of the concrete in a structure, relating the condition of the concrete to the underlying cause or causes of that condition, selecting an appropriate repair material and method for any deficiency found, and using the selected materials and methods to repair or rehabilitate the structure. Guidance is also included on maintenance of concrete and on preparation of concrete investigation reports for repair and rehabilitation projects. Considerations for certain specialized types of rehabilitation projects are also given.

Book Failure Distress and Repair of Concrete Structures

Download or read book Failure Distress and Repair of Concrete Structures written by Norb Delatte and published by Elsevier. This book was released on 2009-10-26 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding and recognising failure mechanisms in concrete is a fundamental pre-requisite to determining the type of repair, or whether a repair is feasible. This title provides a review of concrete deterioration and damage, as well as looking at the problem of defects in concrete. It also discusses condition assessment and repair techniques.Part one discusses failure mechanisms in concrete and covers topics such as causes and mechanisms of deterioration in reinforced concrete, types of damage in concrete structures, types and causes of cracking and condition assessment of concrete structures. Part two reviews the repair of concrete structures with coverage of themes such as standards and guidelines for repairing concrete structures, methods of crack repair, repair materials, bonded concrete overlays, repairing and retrofitting concrete structures with fiber-reinforced polymers, patching deteriorated concrete structures and durability of repaired concrete.With its distinguished editor and international team of contributors, Failure and repair of concrete structures is a standard reference for civil engineers, architects and anyone working in the construction sector, as well as those concerned with ensuring the safety of concrete structures. - Provides a review of concrete deterioration and damage - Discusses condition assessment and repair techniques, standards and guidelines

Book Fracture Mechanics of Concrete

Download or read book Fracture Mechanics of Concrete written by Surendra P. Shah and published by John Wiley & Sons. This book was released on 1995-09-28 with total page 588 pages. Available in PDF, EPUB and Kindle. Book excerpt: FRACTURE MECHANICS OF CONCRETE AND ROCK This book offers engineers a unique opportunity to learn, frominternationally recognized leaders in their field, about the latesttheoretical advances in fracture mechanics in concrete, reinforcedconcrete structures, and rock. At the same time, it functions as asuperb, graduate-level introduction to fracture mechanics conceptsand analytical techniques. Reviews, in depth, the basic theory behind fracture mechanics * Covers the application of fracture mechanics to compressionfailure, creep, fatigue, torsion, and other advanced topics * Extremely well researched, applies experimental evidence ofdamage to a wide range of design cases * Supplies all relevant formulas for stress intensity * Covers state-of-the-art linear elastic fracture mechanics (LEFM)techniques for analyzing deformations and cracking * Describes nonlinear fracture mechanics (NLFM) and the latestRILEM modeling techniques for testing nonlinear quasi-brittlematerials * And much more Over the past few years, researchers employing techniques borrowedfrom fracture mechanics have made many groundbreaking discoveriesconcerning the causes and effects of cracking, damage, andfractures of plain and reinforced concrete structures and rock.This, in turn, has resulted in the further development andrefinement of fracture mechanics concepts and tools. Yet, despitethe field's growth and the growing conviction that fracturemechanics is indispensable to an understanding of material andstructural failure, there continues to be a surprising shortage oftextbooks and professional references on the subject. Written by two of the foremost names in the field, FractureMechanics of Concrete fills that gap. The most comprehensive bookever written on the subject, it consolidates the latest theoreticalresearch from around the world in a single reference that can beused by students and professionals alike. Fracture Mechanics of Concrete is divided into two sections. In thefirst, the authors lay the necessary groundwork with an in-depthreview of fundamental principles. In the second section, theauthors vividly demonstrate how fracture mechanics has beensuccessfully applied to failures occurring in a wide array ofdesign cases. Key topics covered in these sections include: * State-of-the-art linear elastic fracture mechanics (LEFM)techniques for analyzing deformations and cracking * Nonlinear fracture mechanics (NLFM) and the latest RILEM modelingtechniques for testing nonlinear quasi-brittle materials * The use of R-Curves to describe cracking and fracture inquasi-brittle materials * The application of fracture mechanics to compression failure,creep, fatigue, torsion, and other advanced topics The most timely, comprehensive, and authoritative book on thesubject currently available, Fracture Mechanics of Concrete is botha complete instructional tool for academics and students instructural and geotechnical engineering courses, and anindispensable working resource for practicing engineers.

Book Fracture mechanics of concrete Structural application and numerical calculation

Download or read book Fracture mechanics of concrete Structural application and numerical calculation written by George C. Sih and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 289 pages. Available in PDF, EPUB and Kindle. Book excerpt: Concrete has traditionally been known as a material used widely in the construction of roads, bridges and buildings. Since cost effectiveness has always been one of the more important aspects of design, concrete, when reinforced and/or prestressed, is finding more use in other areas of application such as floating marine structures, storage tanks, nuclear vessel containments and a host of other structures. Because of the demand for concrete to operate under different loading and environmen tal conditions, increasing attention has been paid to study concrete specimens and structure behavior. A subject of major concern is how the localized segregation of the constituents in concrete would affect its global behavior. The degree of nonhomogeneity due to material property and damage. by yielding and/or cracking depends on the size scale and loading rate under consideration. Segregation or clustering of aggregates at the macroscopic level will affect specimen behavior to a larger degree than it would to a large structure such as a dam. Hence, a knowledge of concrete behavior over a wide range of scale is desired. The parameters governing micro-and macro-cracking and the techniques for evaluating and observing the damage in concrete need to be better understood. This volume is intended to be an attempt in this direction. The application of Linear Elastic Fracture Mechanics to concrete is discussed in several of the chapters.