1,721,069 research outputs found
Behaviour of prestressed steel beams
No full textThis paper reports on the behavior of simply supported I-shaped cross section steel beams prestressed by tendons. It is well
known that this typology of beams has successfully been used mainly in the past. Prestressed steel beams are lighter than traditional ones
that have the same length and vertical load capacity; this aspect could make them economically advantageous and a viable solution in
many practical situations. This paper analyzes prestressed steel beams having a medium span ranging from 35 to 45 m and which are to
be used as roof structural elements. This study focuses on two parameters that are considered two of the fundamental items for the design:
the number of deviators and the value of the prestressing force. This study has been carried out with nonlinear finite-element analyses that
take into account both mechanical and geometrical nonlinearities. In particular, the behavior of these beams has been investigated up to
failure during tensioning and during loading after tensioning. The effect on the structural response of bracing, which can be only at the
top flange of the beams or at the top and bottom flanges of the beams, also has been considered
Capacity Design–Based Seismic Forces in Floor-to-Beam Connections of Precast Concrete Frames
No full textThe stiffness and strength of roof units and their connections to supporting beams are fundamental parameters to define the
diaphragm behavior of precast structures. In this paper, an analytical method for the calculation of actions in floor-to-beam connections of roof systems without topping slab and without floor-to-floor connections is presented. The proposed procedure can be applied to rectangular single-story precast concrete frames of industrial buildings. One-span, multi-bays regular frames, characterized by symmetry of stiffness and mass distributions are analyzed by assuming floor-to-beam connections with infinite stiffness and strength. The procedure is applied in the perspective of capacity design approach by providing practical formulations for the design and retrofitting of floor-to-beam connections. This approach aims at concentrating the critical regions, where energy dissipation of the structure occurs, at the base of columns designed to fail in bending. An over-resisting behavior of the connections is achieved by over-proportioning them with respect to the resistance of the critical regions. To check the effectiveness of the presented approach, the results obtained with the analytical method are compared with the results of finite element analyses
Modeling approaches suitable for pushover analyses of RC structural wall buildings
No full textIn the current paper the seismic performance of a regular multi-storey precast reinforced concrete structural
wall building vertically connected with ordinary reinforcement is investigated. The structural walls
have different cross section shapes (rectangular, ‘‘U’’, ‘‘L’’ and ‘‘C’’). Some of the construction details of the
structural joints connecting the precast walls horizontally and vertically are briefly described. Different
modeling approaches for pushover analyses, from lower to higher levels of accuracy, have been applied
in order to investigate the applicability of the calculation methods adopted to the study of buildings having
non-rectangular structural walls. In particular the building has been analyzed with a shell model,
implemented by the authors and denoted PARC model, a fiber-element model and a lumped-plasticity
model, implemented by the authors and denoted LPA. The results obtained with the three models in
terms of seismic response of the building proved to be consistent to each other. Hence, for this particular
case, the lumped plasticity model presented, that can be simply applicable in the daily design practice,
gave reliable result
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
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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