Strength of Normal and Inclined Sections of Bent Reinforced Concrete Elements with Zone Reinforcement Made of Steel Fiber

On the basis of theoretical and experimental studies, the prerequisites and the method of calculation of bent and compressed-curved reinforced concrete structures with zone reinforcement made of steel fiber, working under static and short-term dynamic loads, are formulated. In the developed method for calculating the strength of normal and inclined sections, a nonlinear deformation model is implemented, which is based on the actual deformation diagrams of materials. The developed calculation method is brought to the program of calculation of reinforced concrete structures with zone reinforcement of steel fiber under short-term dynamic loading, taking into account the inelastic properties of materials. The numerical studies made it possible to determine the influence of various parameters of steel-fiber reinforcement on the strength of reinforced concrete elements. To confirm the main results of the developed calculation method, experimental studies of reinforced concrete beam structures reinforced with conventional reinforcement and a zone steel-fiber layer are planned and carried out. Experimental studies were carried out under static and short-term dynamic loads. As a result of the conducted experiments, data were obtained that characterize the process of destruction, deformation and cracking of steel-reinforced concrete elements under such types of loading. The dependences of changes in the energy intensity of reinforced concrete structures with zone reinforcement made of steel fiber in the compressed and stretched cross-section zones under dynamic loading are obtained. The effectiveness of the use of fiber reinforcement of normal and inclined sections of bent and compressed-curved elements to improve the strength and deformative.

A Conceptual Model for Situating Purposes in Artificial Institutions

{In multi-agent systems, artificial institutions connect institutional concepts, belonging to the institutional reality, to the concrete elements that compose the system. The institutional reality is composed of a set of institutional concepts, called Status-Functions. Current works on artificial institutions focus on identifying the status-functions and connecting them to the concrete elements. However, the functions associated with the status-functions are implicit. As a consequence, the agents cannot reason about the functions provided by the elements that carry the status-functions and, thus, cannot exploit these functions to satisfy their goals. Considering this problem, this paper proposes a model to express the functions -- or the purposes -- associated with the status-functions. Examples illustrate the application of the model in a practical scenario, showing how the agents can use purposes to reason about the satisfaction of their goals in institutional contexts.

A Chronology of Levinas’s Metaphorics

Many readers of Emmanuel Levinas understand his thought as being oriented only by transcendence and therefore denigrate the immanent dimension of metaphor within his texts. Such readings reduce the complexities of Levinas’s text to a set of polemical, orthodox proclamations such as The Other is Most High and Ethics is First Philosophy. However, Levinas’s work invites us to contemplate not only transcendence, but also the way that immanence emerges though relationships with an infinitude of others, third persons whose voices murmur within the system of language, articulated in concrete elements such as metaphor. Levinas employs metaphor to converse with the inherited ways that temporal becoming has been articulated, recurrently reorienting them to expose a variety of ethical-phenomenological constellations. To expose the dynamics that remain clandestine to the orthodox interpretation, this paper will chronologically trace the development of various families of metaphors such as those of having and doing; those of dimensionality, those of orality, those of familiarity, and those of birth, gender, and death, thereby demonstrating the multitude of roles and perspectival positions assumed by the subject during its temporal becoming.

Influence of the supplementary reinforcement on the shear strength of beams with prefabricated truss stirrups

abstract: This paper presents the results of seven experimental tests in reinforced concrete wide beams, aiming to investigate their performance when subjected to shear, using prefabricated truss stirrups as shear reinforcement, as well as a supplementary reinforcement to control cracks by delamination. The main analysed variables were: position of the supplementary reinforcement, inclination of the shear reinforcement, and spacing between stirrups. Results showed that strength increments of up to 142% were obtained using the prefabricated truss stirrups. Furthermore, the experimental results were compared with the theoretical shear strength estimates of the tested beams, following the recommendations of NBR 6118 (2014), Eurocode 2 (2004), and ACI 318 (2014), in order to evaluate the safety level of these codes when designing concrete elements subjected to shear with the reinforcement used in this paper.

Structural grouting of load-bearing precast concrete elements: Issues and solutions

The purpose of this paper is to raise construction industry awareness regarding structural grouting of precast concrete projects in the United States. Incidents related to structural grouting have occurred with both precast concrete systems and other building systems. Designers, architects, owners, insurance carriers, and the construction industry in general are becoming increasingly aware of deficient grouting installation methods and verification procedures. Concerns include the timeliness of grout installation during the erection process, the lack of grout on some components of finished projects, and the poor quality of installed grout. These concerns pertain to horizontal connection joints of critical load-bearing elements between foundations and precast concrete columns and walls, stacked precast concrete columns, and stacked precast concrete walls. Current building codes and standards provide no requirements and limited guidance for the installation or special inspection of these critical horizontal joints. In an effort to address this gap in building codes and standards, as it specifically relates to precast concrete structural products, some precast concrete producers and erectors are implementing several strategies and new procedures, as noted and further developed in this paper.

Bearing capacity of damaged reinforced concrete beams strengthened with metal casing

Experimental data on the bearing capacity of damaged reinforced concrete beams with the dimensions of 2000×200×100 mm, reinforced with prestressed metal casings, are presented. Damaging in the form of through normal and crossing inclined cracks, as well as excessive vertical moving of the beam were obtained during previous tests for the effect of high-level transverse alternating loads.The authors of the article have developed a method and equipment for restoring and strengthening damaged reinforced concrete beams using a casing. Beams are manufactured and tested in accordance with the three-level design of an experiment.Previously damaged and reduced to the ultimate (pre-emergency) state, the beams were strengthened with the declared method and equipment, and then retested. New data on the bearing capacity of ordinary and damaged beams, as well as reinforced concrete elements strengthened with casings and tested for the action of transverse forces and bending moments were obtained. The research results are presented in the form of experimental-statistical dependences of the bearing capacity of the support areas, deformability and crack resistance of the investigated elements on the ratio of the most significant design factors and external factors. A comparative analysis of the influence of these factors on the main parameters of the bearing capacity of ordinary as well as previously damaged and then strengthened test beams is carried out.The possibility and appropriateness of using the proposed method of strengthening reinforced concrete beams damaged by through normal and cross-inclined force cracks in the conditions of an existing production has been experimentally proved.

STRENGTH OF CONCRETE UNDER LOCAL COMPRESSION TAKING INTO ACCOUNT THE RELATIONSHIP OF THE ELEMENT HEIGHT TO THE SIZE OF THE LOADING AREA

Formulation of the problem. Reliability of buildings and structures from reinforced concrete largely depends on efficiency of construction solutions of supporting areas and joins of elements of bearing systems. At the same time, an important place is given to the issues of ensuring their bearing capacity. One of the ways to solve this problem is to increase the strength characteristics of concrete, in particular by using basalt fiber. The purpose of the article is to improve the method of calculating the strength of concrete elements under the local compression on a general theoretical basis and to clarify the impact on the strength of determining factors. Conclusion. To calculate the strength of concrete elements under the local compression, the theory of concrete plasticity is promising. The application of the variational method and the principle of virtual velocities is proposed. According to research, the strength of concrete, in addition to the ratio of the area of application of the load and the cross-sectional area, is affected by the ratio of the height of the element to the width of the stamp and both characteristics of concrete strength. The proposed kinematic failure schemes have found experimental confirmation. Analysis of test results of concrete elements and assessment of their strength on the basis of the theory of plasticity allowed making the program of experimental research of fibroconcrete on basalt fibers under local compression.