Principles Of Compatibility Research Articles

Analysis and design of rehabilitated built-up hybrid steel compression members

Compression members in steel bridges designed before 1960 may be deficient according to current design code requirements and so require strengthening. This paper explores the response of steel wide-flange columns reinforced with new steel flange cover plates, accounting for: residual and locked-in dead-load stresses; different yield strengths of the original W shape and the new cover plates; initial out-of-straightness; and load eccentricity at the member ends. A refined numerical analysis model is formulated and validated that computes the compressive resistance from principles of equilibrium, compatibility, and force–deformation relationships. Parametric studies conducted indicate that the capacity of the reinforced column is relatively insensitive to the magnitude of the locked-in dead-load stress in the original member, and that the strong axis capacity is insensitive to the magnitude of the residual stresses in the original member. A preliminary approach for designing strengthening for these members is presented and illustrated with an example calculation.

Flexural Strength Design of Concrete Beams Reinforced with High-Strength Steel Bars

Current design requirements limit the allowable design strength of high-strength steel reinforcements to 80 ksi (550 MPa), which limits engineers from fully using the enhanced strength characteristics of low-carbon and chromium high-strength steel. In this paper, a methodology is presented for the flexural strength design of concrete beams reinforced with high-strength reinforcing steel that conforms to the requirements of ASTM A1035-07. The design method is based on simple analysis techniques that satisfy fundamental principles of equilibrium and compatibility. Strain limits for tension-controlled sections and compression-controlled sections are proposed that are consistent with the approach of the current and past ACI 318 Codes. The proposed method is compared with previously-reported experimental results, and the application of the proposed method is demonstrated by a numerical design example. Findings indicate that flexural members designed using the proposed design methods and criteria have comparable flexural strength characteristics with members designed according to current ACI 318 requirements, using Grade 60 (400 MPa) and Grade 75 (520 MPa) reinforcing steel.

Fatigue and Overloading Behavior of Steel–Concrete Composite Flexural Members Strengthened with High Modulus CFRP Materials

Due to corrosion and the continuous demand to increase traffic loads, there is a need for an effective system which can be used to repair and/or strengthen steel bridges and structures. This paper describes an experimental program, recently completed, to investigate the fundamental behavior of steel–concrete composite scaled bridge beams strengthened with new high modulus carbon fiber-reinforced polymer (HM CFRP) materials. The behavior of the beams under overloading conditions and fatigue loading conditions was studied as well as the possible presence of shear lag at the interface of the steel surface and the CFRP strengthening material. The test results are compared to an analytical model based on the fundamental principles of equilibrium and compatibility, to predict the behavior of the strengthened steel–concrete composite beams. Based on the findings of this research work, combined with other work in the literature, a design guideline is proposed for the use of HM CFRP for strengthening the steel fle...

Development of Neural Network Based Hysteretic Models for Steel Beam-Column Connections Through Self-Learning Simulation

Beam-column connections are zones of highly complex actions and deformations interaction that often lead to failure under the effect of earthquake ground motion. Modeling of the beam-column connections is important both in understanding the behavior and in design. In this article, a framework for developing a neural network (NN) based steel beam-column connection model through structural testing is proposed. Neural network based inelastic hysteretic model for beam-column connections is combined with a new component based model under self-learning simulation framework. Self-learning simulation has the unique advantage in that it can use structural response to extract material models. Self-learning simulation is based on auto-progressive algorithm that employs the principles of equilibrium and compatibility, and the self-organizing nature of artificial neural network material models. The component based model is an assemblage of rigid body elements and spring elements which represent smeared constitutive behaviors of components; either nonlinear elastic or nonlinear inelastic behavior of components. The component based model is verified by a 3-D finite element analysis. The proposed methodology is illustrated through a self-learning simulation for a welded steel beam-column connection. In addition to presenting the first application of self-learning simulation to steel beam-column connections, a framework is outlined for applying the proposed methodology to other types of connections.

ＦＲＰシートの適材適所接着によるＦＲＰ‐ＲＣハイブリッド構造物の曲げ構造性能に関する研究

A novel hybrid FRP-concrete sttuctural system was proposed in past study. In the study, high strength type of CFRP sheets is axially bonded on the bottom surface of the concrete core to cany tensile load while GFRP sheets with higher rupture strains are hoop-directionally wrapped to bear the shear load. The GFRP sheets also provide confinement to concrete core and delay the debonding of CFRP sheets. A minimum reinforcement ratio of steel rebars is used to control the localization and propagation of flexural cracks. In this study, a series of 4-point bending experiments were carried out to study the performances of the hybrid FRP with high modulus type of CFRP sheets, T grass fiber sheets and Dyneema fiber sheets and concrete hybrid beams. Based on the principles of strain compatibility and equihbrium, an iterative analytical model is developed to evaluate the flexural behavior of the hybrid beam specimens.

Innovative externally bonded FRP/concrete hybrid flexural members

A novel hybrid FRP–concrete structural system is proposed in this paper. CFRP sheets with high strengths are axially bonded on the bottom surface of the concrete core to carry tensile load while GFRP sheets with high rupture strains are hoop-directionally wrapped to bear the shear load. The GFRP sheets also provide confinement to concrete core and prevent premature debonding of CFRP sheets. A minimum reinforcement ratio of rebars is used to control the localization and propagation of flexural cracks. Instead of conventional shear keys of hybrid systems, an epoxy resin bonding technique is adopted to assure composite effect between FRP and concrete and hence avoid buckling failure mode of FRP shell. A series of 4-point bending experiments were carried out to study the performances of the proposed hybrid FRP–concrete beams. Based on the principles of strain compatibility and equilibrium, an iterative analytical model is developed to evaluate the flexural behavior of the hybrid beam specimens.

Strengthening of Masonry Walls against Out-of-Plane Loads Using Fiber-Reinforced Polymer Reinforcement

Thirty masonry walls strengthened using three different fiber-reinforced polymer (FRP) systems, with three anchorage methods, were fabricated and tested under a concentrated load over a 100 mm square area or a patch load over a 500 mm square area. The test results indicated a significant increase in the out-of-plane wall strength over the unstrengthened wall. While failure occurred in the unstrengthened wall by bending, four different modes of failure, that is, punching shear through the bricks, debonding of FRP reinforcement from the masonry substrate, crushing of brick in compression, and tensile rupture of the FRP reinforcement, were observed in the strengthened walls, depending on the types and configurations of FRP and anchorage systems. With appropriate surface preparation and anchorage systems, premature failure due to FRP debonding is prevented. Based on the principles of strain compatibility and force equilibrium, simple analytical models are presented to predict the ultimate load-carrying capaci...

Immune effects of blood transfusion.

Blood is a complicated tissue that has been routinely applied over the past century. Since the recognition of the principles of species specificity (1818) and major compatibility for red cell antigens (1900), considerable attention has been given in the second half of this century to leukocyte-determined immune effects following transfusion. Most reactions are febrile and nonhemolytic and show, in limited situations, true relation to immune activity of transfused white blood cells. The complete picture is not yet finished; however, the more important immune effects are stimulation and modulation, tolerance and suppression. Here most work done is ex vivo and in animal experiments. Little clinical evidence has been obtained or assessment done. Most publications therefore relate to laboratory work, extrapolating results to the bedside. The most interesting publication over the review period with regard to the core immune effects of blood transfusion relates to measured concentrations of active, soluble molecules like HLA class I and II and Fas ligand molecules and to their in vitro immunomodulating effect as well as effects on induction of apoptosis. Stored red cell preparations show an increase in soluble molecules and death of viable leukocytes. Platelet preparations show similar phenomena, although information on numbers of white blood cells and storage conditions are lacking. The authors propose selective use of these aged components in specific clinical settings to allow immune suppression, induction of cell anergy, and apoptosis, whereas fresher products not showing increased levels of soluble molecules could be applied in clinical settings in which immunosuppression is not wanted. No reference is found to scientifically support and substantiate the global universal leukodepletion movement.

Strengthening of reinforced concrete beams with externally bonded fiber-reinforced-plastic plates: design guidelines for shear and flexure

This paper presents a comprehensive design approach for reinforced concrete flexural beams and unidirectional slabs strengthened with externally bonded fiber-reinforced-plastic (FRP) plates. The approach complies with the Canadian Concrete Standard. The paper is divided into two parts, namely flexural strengthening and shear strengthening. In the first part, analytical models are presented for two families of failure modes: classical modes such as crushing of concrete in compression and tensile failure of the laminate, and premature modes such as debonding of the plate and ripping off of the concrete cover. These models are based on the common principles of compatibility of deformations and equilibrium of forces. They can be used to predict the ultimate strength in flexure that can be achieved by such elements, given the FRP cross-sectional area, or conversely, the required FRP cross-sectional area to achieve a targeted resisting moment for rehabilitated flexural elements. In the second part, design equations are derived to enable calculation of the required cross-sectional area of shear lateral FRP plates or strips for four plating patterns: vertical strips, inclined strips, wings, and U sheet jackets. A step by step procedure is also presented along with an easy to use flow chart. Finally, a numerical design example is provided to demonstrate the applicability of the approach. This study is believed to be timely and very useful for the practicing engineer.Key words: reinforced concrete, beams, slabs, strengthening, FRP, plates, design, flexure, shear, mode of failure, adhesive.

Didactics of history and historical consciousness: the problem of interrelation

The paper discusses the general principles of compatibility between history and social science studies. Modernity has transformed the ancient belief that historia est magistra vitae (Cicero) and one common discourse of history has split into two different parts: academic history and didactics of history. This division has fostered the development of scientific history but, on the other hand, the gap between academic history and historical teaching has increased. Gradually, didactics of history have lost their raison d'être. How could didactics of history transfer the knowledge that was articulated in the discourse of professional and academic ("esoteric") history? The contemporary renaissance of didactics of history was caused by the newly articulated multidimensional subject, historical consciousness. The analysis of the structure of historical consciousness and the investigation of the factors of its development, etc., are building the bridges between the parts of the divided discourse of history and enabling history to regain its lost function.

Experimental and analytical investigation of FRP strengthened beam response: Part I

Beam tests on 1·0 m long reinforced concrete beams with fibre reinforced plastic plates epoxy-bonded to their soffits are reported. In these tests, a simple parametric study has been carried out in which the plate area, plate aspect ratio, plate material and the method of anchoring the plate ends have been varied. The effects of these variables on overall behaviour are discussed. An iterative analytica1 method which uses the principles of strain compatibility and equilibrium has been used for predicting the strengthened beam response. The use of both a cracked and a partially cracked section including steel strain hardening have been considered in developing the model. The analytica1 and experimental responses are compared and observations noted.

Polymer-Modified Asphalt Cements Used in the Road Construction Industry: Basic Principles

Modified binders—obtained by adding thermoplastic macromolecular systems of plastomers or elastomers to traditional pure asphalt cements for road construction—have existed for more than 20 years. These products are still poorly understood scientifically. Significant research must be undertaken to better understand binder relationships between composition, structure, and properties, and the relationships between hot mix performance (rutting, fatigue, thermal cracking) and the characteristics of the modified binders as measured in the laboratory. The current state of knowledge regarding these issues is presented along with a discussion of the basic principles of bitumen-polymer compatibility, the mechanism for modification, and the effect of the components on the properties of the modified binders. Several specific problems related to the use of these products are presented.

Polymer-Modified Asphalt Cements Used in the Road Construction Industry: Basic Principles

Modified binders—obtained by adding thermoplastic macromolecular systems of plastomers or elastomers to traditional pure asphalt cements for road construction—have existed for more than 20 years. These products are still poorly understood scientifically. Significant research must be undertaken to better understand binder relationships between composition, structure, and properties, and the relationships between hot mix performance (rutting, fatigue, thermal cracking) and the characteristics of the modified binders as measured in the laboratory. The current state of knowledge regarding these issues is presented along with a discussion of the basic principles of bitumen-polymer compatibility, the mechanism for modification, and the effect of the components on the properties of the modified binders. Several specific problems related to the use of these products are presented.

Qualitative reasoning and the representation of fundamental principles in structural engineering

Qualitative reasoning is a methodology for deriving the behavior of a device from a declarative representation of relevant fundamental principles and a high-level description of the device. This article and its companion present a qualitative reasoning framework, named the space-centered framework, for reasoning about the behavior of structural systems subjected to loads. The framework includes a representation of the topology and geometry of a structure, and the fundamental principles of equilibrium, compatibility and force-deformation relationships. A parameter, such as a displacement or an internal force, is represented qualitatively by its algebraic sign and its relationship in magnitude with other parameters in the model. Component qualitative states incorporate the fundamental principles for a class of components, such as frame members or supports. The conjugate analogy between the equilibrium and compatibility laws is recognized in the representation. Processes acting between components represent fundamental principles of equilibrium and compatibility at the connections. A companion paper presents the inference strategy for the space-centered framework and its application to qualitative analysis of conceptual designs of structures.

Musical Notation for the Keyboard: An Examination of Stimulus–Response Compatibility

The principles of stimulus-response compatibility were used to provide a performance evaluation of an experimental notation for the keyboard in which pitch varies horizontally in visual space. Subjects performed a choice reaction time task using either the horizontal notation or a more traditional vertical notation. Half the subjects in each notation group were provided white noise and half pitch-varying feedback with responses. Responses were reliably faster with the horizontal display. Further, the superiority of the horizontal display was not dependent on the nature of the feedback. In a second experiment, performance of musicians and nonmusicians was compared using the horizontal and vertical notations. Performance by musicians was equivalent with horizontal and vertical displays and uniformly better than nonmusicians. The findings fail to support the argument that horizontal visual representations will be less useful in musical tasks because they will be incompatible with the mental representation of pitch as varying vertically from ‘low’ to ‘high’.

Book Review: General Principles of Electromagnetic Compatibility, 3rd Ed.

Book Review: General Principles of Electromagnetic Compatibility, 3rd Ed.

Principles of S-C-R compatibility with spatial and verbal tasks: the role of display-control location and voice-interactive display-control interfacing.

A pilot's tasks may be categorized into those that demand predominantly verbal operations and those that are spatial. We describe two experiments that define two principles of compatibility of interfacing such tasks with displays and controls. The first, based upon hemispheric laterality effects, defines compatibility according 10 the display location and the response hand; the second defines compatibility according to the modality of display (auditory and visual) and response (manual and speech). Verbal tasks are best served by auditory inputs and speech response, whereas spatial tasks are best served by visual-manual channels. In both experiments, these principles of compatibility are confirmed under dual-task conditions. We describe their implications for cockpit design.

The Concept of Musical Consonance: A Link between Music and Psychoacoustics

This paper is a presentation of the essentials of a new concept and foundation of musical consonance described by the present author in German in Acustica 36,121-137 (1976). Musical consonance is considered from the terminological, musical, conceptual, and psychoacoustic aspects. An appropriate definition of musical consonance is given, based on the principles governing tonal music. Recent results on psychoacoustic evaluation of consonance, which at first glance appear to be in conflict with musical experience, can be reconciled by a two-component concept of musical consonance. The first component is called sensory consonance; it represents the graded absence of annoying factors and is not confined to musical sounds, that is, not music specific. The second component of musical consonance is called harmony; it represents the typical, musicspecific principles of tonal affinity, compatibility, and fundamental-note relation (root). This concept is discussed in the context of Helmholtz's work on Konsonanz and Klangverwandtschaft. Helmholtz's work turns out to be an excellent basis of modern solutions to the consonance problem, as much of it still is valid, while the remainder can readily be replaced by more appropriate new solutions. The psychoacoustic foundations of sensory consonance, as provided by modern psychoacoustics, are largely identical with those found by Helmholtz. With regard to harmony, that is, the music-specific component of musical consonance, a new psychoacoustic foundation is provided by the established principles of virtualpitch perception. Several consequences and prospects of the concept for musical science are briefly considered.

Matching methods for integrated-optics devices and fiber-optic communication lines (review)

A review is given of the literature on the principles of compatibility and on matching methods suitable for integrated-optics devices and fiber-optic communication lines. The general principles of compatibility of fiber and other waveguides are given. A detailed analysis is made of the main coupling methods, including the direct excitation of the end face and the optical tunneling method. Devices for matching single-mode and multimode waveguides to various types of fiber waveguides are discussed comprehensively. Methods and devices for matching planar and three-dimensional waveguides are considered as well as corresponding methods for matching radiation sources (semiconductor lasers and light-emitting diodes) to fiber and other waveguides. General trends and principal directions of further research are considered.

Compatibility of two-dimensional strains and rotations along strain trajectories

A study of the compatibility of strains and rotations is necessary for a proper understanding of deformation patterns. Principles of compatibility also underlie all methods for removing the effects of deformation and finding the pretectonic shape of deformed regions. The object of this paper is to derive compatibility equations in a direct way and in a simple form which can be interpreted geometrically. This is done using sets of orthogonal curvilinear coordinates parallel to strain trajectories. As a result, all shear components vanish and only principal strains appear in the equations. Such advantages are obtained at the expense of the extra complexity of curvilinear coordinates compared with Cartesian ones. Orthogonal curvilinear coordinates are described first, with particular reference to curvature. Compatibility of strains and rotations is then discussed by comparing curvatures of trajectories in the undeformed and deformed states. Results are compared with previous theoretical work and numerical methods.