1,638 research outputs found
An Active Turbulence Generator based on the Vortex Method for Simulation of a Complex Aerodynamic Admittance for Bridge Decks
No full textRecalculation of Laboratory Tests with the Extended Zone Method
No full textThe Advanced Calculation Method given in EN 1992-1-2 is accepted by engineers and building authorities for the determination of the fire resistance of reinforced concrete structures. It has been developed originally for the recalculation of laboratory tests: the time of failure is calculated for a given layout of reinforcement. But in the structural analysis of concrete columns, the area of reinforcement has to be calculated for a desired fire resistance. Design methods and strategies, which are suitable for the design of concrete compression members, require constant material properties and strain limits, which are not given for the Advanced Calculation Method. Therefore Achenbach and Morgenthal have proposed an extension of the Zone Method by Hertz, suitable for the implementation in commercial design software. In this paper, this Extended Zone Method is used to recalculate laboratory tests to determine the accuracy of this method. A statistical analysis of the results is performed to evaluate the statistical key data of the Extended Zone Method
"La materia quando inizia a soffrire": Denial Figures in Guido Morselli's Work
No full textopenIl presente lavoro si propone di indagare la questione della crisi del soggetto così come discussa dall'autore italiano Guido Morselli, nelle diverse sedi dei romanzi, della produzione saggistica e del diario personale. Da qui si analizzeranno temi quali il solipsismo e gli interrogativi esistenziali, fin dai loro primi riverberi nella filosofia centro-europea di fine Ottocento, inizio Novecento.The present work aims yo investigate the issue of the crisis of the subject, as it is discussed by the Italian author Guido Morselli, on his novels, essays and personal diary. We will also analyze topics such as solipsism and existential questions from their first reverberations on the late eighteen century and early nineteen century middle European philosophy
Aerodynamic Analysis of Slender Vertical Structure and Response Control with Tuned Mass Damper
No full textAnalysis of vortex induced vibration has gained more interest in practical held of civil engineering. The phenomenon often occurs in long and slender vertical structure like high rise building, tower, chimney or bridge pylon, which resulting in unfavorable responses and might lead to the collapse of the structures. The phenomenon appears when frequency of vortex shedding produced in the wake area of body meet the natural frequency of the structure. Even though this phenomenon does not necessarily generate a divergent amplitude response, the structure still may fail due to fatigue damage.
To reduce the effect of vortex induced vibration, engineers widely use passive vibration response control system. In this case, the thesis studies the effect of tuned mass damper. The objective of this thesis is to simulate the effect of tuned mass damper in reducing unfavorable responses due to vortex induced vibration and initiated by numerical model validation with respect to wind tunnel test report. The reference structure that being used inside the thesis is Stonecutter Bridge, Hongkong.
A numerical solver for computational uid dynamics named VX ow which developed by Morgenthal [6] is utilized for wind and structure simulation. The comparison between numerical model and wind tunnel result shows 10% maximum tip displacement diference in the model of full erection freestanding tower. The tuned mass damper (TMD) model itself built separately in finite element software SOFiSTiK, and the efective damping obtained from this model then applied inside input modal data of VX ow simulation. A single TMD with mass ratio of TMD 0.5% to the mass of first bending frequency, the maximum tip displacement is measured to be average 67% reduced.
Considering construction limitation and robustness of TMD, the effects of multiple TMD inside a structure are also studied. An uncoupled procedure of applying aeroelastic loads obtained from VX
ow inside finite element software SOFiSTiK is also done to observe the optimum distribution and optimum mass ratio of multiple tuned mass damper. The rest of the properties of TMD are calculated with Den Hartog's formula. The results are as follows: peak displacement in the case of multiple TMD that distributed with polynomial spacing achieve 7.8% more reduction performance than
the one that distributed with equal spacing. Optimum mass of tuned mass damper achieved with ratio 1.25% mass of first bending frequency corresponds to across wind direction
Structural Optimization of Composite Cross-Sections and Elements using Energy Methods
No full textStructural optimization has gained considerable attention in the design of structural engineering structures, especially in the preliminary phase. This study introduces an unconventional approach for structural optimization by utilizing the Energy method with Integral Material Behavior (EIM), based on the Lagrange’s principle of minimum potential energy. An automated two-level optimization search process is proposed, which integrates the EIM, as an alternative method for nonlinear structural analysis, and the bilevel optimization. The proposed procedure secures the equilibrium through minimizing the potential energy on one level, and on a higher level, a design objective function. For this, the most robust strategy of bilevel optimization, the nested method is used. The function of the potential energy is investigated along with its instabilities for physical nonlinear analysis through principle examples, by which the advantages and limitations using this method are reviewed. Furthermore, optimization algorithms are discussed. A numerical fully functional code is developed for nonlinear cross section, element and 2D frame analysis, utilizing different finite elements and is verified against existing EIM programs. As a proof of concept, the method is applied on selected examples using this code on cross section and element level. For the former one a comparison is made with standard procedure, by employing the equilibrium equations within the constrains. The validation of the element level was proven by a theoretical solution of an arch bridge and finally, a truss bridge is optimized. Most of the principle examples are chosen to be adequate for the everyday engineering practice, to demonstrate the effectiveness of the proposed method. This study implies that with further development, this method could become just as competitive as the conventional structural optimization techniques using the Finite Element Method
On systematic approaches for interpreted information transfer of inspection data from bridge models to structural analysis
No full textIn conjunction with the improved methods of monitoring damage and degradation processes, the interest in reliability assessment of reinforced concrete bridges is increasing in recent years. Automated imagebased inspections of the structural surface provide valuable data to extract quantitative information about deteriorations, such as crack patterns. However, the knowledge gain results from processing this information in a structural context, i.e. relating the damage artifacts to building components. This way, transformation to structural analysis is enabled. This approach sets two further requirements: availability of structural bridge information and a standardized storage for interoperability with subsequent analysis tools. Since the involved large datasets are only efficiently processed in an automated manner, the implementation of the complete workflow from damage and building data to structural analysis is targeted in this work. First, domain concepts are derived from the back-end tasks: structural analysis, damage modeling, and life-cycle assessment. The common interoperability format, the Industry Foundation Class (IFC), and processes in these domains are further assessed. The need for usercontrolled interpretation steps is identified and the developed prototype thus allows interaction at subsequent model stages. The latter has the advantage that interpretation steps can be individually separated into either a structural analysis or a damage information model or a combination of both. This approach to damage information processing from the perspective of structural analysis is then validated in different case studies
Nonlinear Numerical Modelling of Cable Elements in Bridges for Dynamic Analysis
No full textIdentifying cable force with vibration-based methods has become widely used in engineering practice due to simplicity of application. The string taut theory provides a simple definition of the relationship between natural frequencies and the tension force of a cable. However, this theory assumes a perfectly flexible non-sagging cable pinned at its ends. These assumptions do not reflect all cases, especially when the cable is short, under low tension forces or the supports are partially flexible. Extradosed bridges, which are distinguished from cable-stayed bridges by their low pylon height, have shorter cables. Therefore the application of the conventional string taut theory to identify cable forces on extradosed bridge cables might be inadequate to identify cable forces. In this work, numerical modelling of an extradosed bridge cable saddled on a circular deviator at pylon is conducted. The model is validated with the catenary analytical solution and its static and dynamic behaviours are studied. The effect of a saddle support is found to positively affect the cable stiffness by geometric means; longer saddle radius increases the cable stiffness by suppressing the deformations near the saddle. Further, accounting the effects of bending stiffness in the numerical model by using beam elements show considerable deviation from models with truss elements (i.e. zero bending stiffness). This deviation is manifested when comparing the static and dynamic properties. This motivates a more thorough study of bending stiffness effects on short cables. Bending stiffness effects are studied using two rods connected with several springs along their length. Under bending moments, the springs resist the rods' relative axial displacement by the springs' transverse component. This concept is used to identify bending stiffness values by utilizing the parallel axis theorem to quantify ratios of the second moment of area. These ratios are calculated based on the setup of the springs (e.g. number of springs per unit length, transverse stiffness, etc...). The numerical model based on this concept agrees well with the theoretical values computed using upper and lower bounds of the parallel axis theorem. The proposed concept of quantifying ratios of the second moment of area using springs as connection between cable rods is applied on an actual extradosed bridge geometry. The model is examined by comparison to the previously validated global numerical model. The two models showed good correlation under various changing parameters. This allowed further study of the effects of stick/slip behaviour between cable rods on an actual bridge geometry
"Sailing around the World (1857-1859). Colonial Patterns, Native Societies, Global Resources in the Circumnavigation of the Austrian Frigate Novara"
No full textThis essay by Guido Abbattista analyzes the Austrian frigate Novara’s circumnavigation (1857–1859) as a paradigmatic case of nineteenth-century global exploration, set within the broader context of European imperial expansion and scientific ambition. Abbattista demonstrates how the Novara expedition, Austria’s first global voyage, was not only a naval and scientific enterprise but also a vehicle for projecting imperial prestige, asserting national identity, and gathering knowledge about colonial patterns, native societies, and global resources. Drawing on official reports, scientific publications, and ethnographic collections, the essay situates the Novara alongside other Austrian and European voyages, highlighting its role in consolidating Austria’s place on the world stage. The author explores the ideological underpinnings of the mission, especially as articulated by Karl von Scherzer, who framed the journey in terms of Eurocentric progress, racial hierarchies, and the civilizing mission of Europe—particularly the “Anglo-Saxon” model. The essay critically examines how the Novara’s documentation and collections contributed to museums and scientific institutions, while also reflecting the contradictions and exclusions of imperialist worldviews. Ultimately, Abbattista argues that the Novara expedition exemplifies the entanglement of science, empire, and global modernity, offering insight into the construction of “global Europeanness” and the enduring legacies of colonial encounters
Erratum to: Association Study between Coronary Artery Disease and rs1333049 Polymorphism at 9p21.3 Locus in Italian Population (Journal of Cardiovascular Translational Research, (2017), 10, 5-6, (455-458), 10.1007/s12265-017-9758-9)
No full textThe author affiliation for both Guido Iaccarino and Michele Ciccarelli is Medicine, Surgery and Dentistry, Scuola Medica Salernitana, University of Salerno. The currently mentioned affiliations (Department of Advanced Biomedical SciencesFederico II University NaplesItaly and IRCCS SDN Istituto di Ricerca Diagnostica e Nucleare Naples Italy respectively) are not correct
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