1,721,117 research outputs found
Influence of strands corrosion on the flexural behavior of prestressed concrete beams
No full textIn this paper, the research goal was the determination of the flexural response of corroded pre-stressed reinforced
concrete beams (PC). A simplified flexural model is bases on the calcualus of the moment and curvature/
deflection curves for simply supported beam under uniformly distributed and concentrated loads. Primary
research outcomes was the introduction in flexural model of the effects of pitting corrosion though the reduction
of area, of the mechanical properties of steel strands and of the loss of bond of steel strands of precast pretensioned beams
Out-of-Plane Behavior of URM Infill: Accuracy of Available Capacity Models
No full textThe aim of this paper is to check the accuracy of analytical capacity models available for the prediction of out-of-plane strength of unreinforced masonry (URM) infill walls. The accuracy of the available models is checked by detailed comparison with the existing experimental results. In doing so, both types of capacity models are evaluated: Type I for the prediction of the strength in the undamaged state, and Type II for the prediction of strength reduction in the in-plane damaged state. Results from the calculations are discussed, and the best among the available models are recommended. Furthermore, the influence of orthotropy of the infill masonry in the out-of-plane capacity predicted by the models is discussed. The paper also highlights the prospect of using the capacity models in the cases of infill-beam gap and infill with openings. In the paper, the best pairs of models (composed by a model for the prediction of the out-of-plane strength in the undamaged state and a model for the prediction of the reduction of the out-of-plane strength in the damaged state, not necessarily provided by the same author) for URM infill walls, are suggested for the first time
Residual out-of-plane capacity of infills damaged by in-plane cyclic loads
No full textDuring earthquakes, infills are subjected to In-Plane (IP) and Out-Of-Plane (OOP) actions. In the case of strong earthquakes, infills may progressively change their mechanical behavior resulting in a reduction of IP and OOP stiffness and strength. Recent earthquakes have proved that the OOP collapse of infills is a diffused mechanism also for buildings designed to resist seismic events in agreement to the most modern codes. This is potentially a very dangerous event with risk for human health. The strong interaction between IP and OOP behavior of infills traduces in a progressive reduction of the OOP strength. The IP damaging loads may cause a loss of the OOP capacity not predicted during the design process or during the safety assessment. Unfortunately, a very low number of experimental tests is available in the literature that does not allow definitively reliable prediction laws for the degrading of the OOP mechanical properties. Further, only in few cases codes suggest adequate strategies to face this question. For what above, in this paper the reduction of OOP stiffness and strength because of the IP damage is studied by an extended numerical experimental campaign based on FE models to be considered as complementary of the few laboratory experimental tests available in the literature. On the base of the numerical results, a proposal for the prediction of the variation of the mechanical characteristics of infills with respect to OOP actions is presented after an extended discussion on the existing strategies. The nonlinear behavior of infills and the arch effect between infill and the surrounding frame, where effective, have been replicated by the FE models here discussed, trying to simulate the real case of unreinforced masonry (URM) infills
Practical calculus methods for flexural response of shallow beam foundation
No full textIn this work, the behavior of reinforced concrete (RC) beams on a soil foundation subjected to concentrated vertical loads and bending moments in both the elastic and the plastic phases was examined. Some of the simplified methods for hand calculations available in the literature, which are useful for the preliminary design of the foundation structures, are reviewed. A simplified plastic calculation method was developed. The method examines the limit cases of partial or full plasticization of soil and the formation of plastic hinges in the beam with elastic or plasticized soil. The proposed method showed good agreement with others in the literature. The purpose of the proposed method was to provide a simple calculation tool useful for calculating the foundation’s bearing capacity and for verifying the overstrength of the soil-foundation complex compared to that of the beam alone. The method highlights that the plastic resources of the soil-foundation complex depend not only on the characteristics of the soil such as cohesion, friction angle, and constant back soil, but also on the geometrical and mechanical characteristics of the foundation beam and on the characteristics of the vertical load (intensity, eccentricity). It was also shown that the maximum ratio of longitudinal steel bars should be determined to ensure the strength hierarchy with the plasticization of RC beams before soil plasticizatio
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Erythematous cutaneous macules: an uncommon, challenging presentation of T-lymphoblastic lymphoma
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