Preliminary analyses of an innovative solution for reducing seismic damage in steel-concrete hybrid-coupled walls

Hybrid steel-concrete structures used as earthquake-resistant systems are an interesting solution for buildings in seismic prone areas, combining in effective ways the benefits of concrete and steel. In this context, an innovative single-pier hybrid coupled wall (SP-HCW), made of a single reinforced concrete wall coupled to two steel side columns by means of steel link, was recently proposed. The system is conceived to reduce the damage in the reinforced concrete wall while concentrating dissipation to the replaceable links. Although the numerical analyses for this innovative solution showed encouraging seismic performances and the desired ductile global behaviour, bottom zones of the concrete wall might experience undesired damages. Starting from the first proposed SP-HCW, in this study a new solution for its base is presented and preliminary investigated, i.e., the wall is designed as pinned at the base and equipped with additional vertical dissipative devices. In this way, this new configuration is expected to achieve lower damage of the wall without reducing its dissipative capacity. In this article the results of preliminary pushover analyses are discussed to evaluate the expected performances of the proposed structural solution

Steel-based applications in earthquake-prone areas

Steel-Earth project aims at distributing among technicians, engineers, design companies and standardization bodies the results of three past RFCS projects (Steel-Retro [3], Opus [2] and PrecaSteel [1]), providing useful tools for the design and for the retrofit of existing buildings. Technical documents and practical applications to case studies, regarding design of steel and composite steel/concrete buildings and innovative steel-based techniques for the retrofit of existing r.c. and masonry constructions, have been elaborated and collected into a volume distributed during the final workshop of the dissemination project. Pre-normative and background documents concerning the design of steel and composite structures and the rehabilitation of existing constructions have been prepared. A lot of attention has been paid to the analysis of the influence of overstrength factors on the seismic design of steel and composite structures. The prepared documents have been distributed to the attending people and to the members of WG 2 (CEN/TC 250/SC 8/WG 2 “Steel and Composite Structures”) during the final workshop of the project. Technical sheets, working examples and background documents have been translated into several languages (German, French, Italian, Romanian and Greek) and are free available on the website of the project (https://www.steelconstruct.com/site/), where information regarding Steel-Earth are also presented.11 Workshops in Italy, Greece, Germany, Belgium, Portugal, Spain and Romania and 5 conferences in Emilia-Romagna have been organized, as well as 2 practical courses for engineers and academic people in Pavia (Italy). Flash-drives with the technical documents and applications elaborated in Steel-Earth have been distributed to the attending people

A morphology study on sclerofoams

A morphology study on sclerofoam

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Quantitative structural assessment of rat tibial epiphhyseal explants kept in microgravity conditions

It is well verified that protracted exposure to microgravity conditions leads to physiological modifications in humans. During spaceflight, the most important variations concern the skeletal system. In fact, a decrease in gravitational loading induces significant bone changes in man and experimental animals in terms of bone loss and mechanical properties decay. Although several hypotheses have been formulated, the mechanisms of spaceflight-induced bone modifications are still mostly unknown. Instead, it is widely accepted that the mechanical properties of cancellous bone are related not only to mineral content, but also to trabecular micro-architecture arrangement. This work aims to investigating the long-term effects of weightlessness conditions on the structural and mechanical properties of cancellous bone samples kept, in vitro, in simulated microgravity conditions. To simulate microgravity conditions, a particular in vitro 3D organ culture model, based on the Rotatory Cell Culture System (RCCSTM) bioreactor, was applied to rat tibial bone fragments (proximal epiphysis). The RCCSTM represents the unique existing bioreactor operating on the Earth\u2019s surface capable to reproduce, in vitro, optimal conditions to simulate microgravity. A quantitative evaluation of the changes in the bone mechanical properties was possible by using a 3D numerical model based on the Cell Method, which allows to estimate, and, subsequently, compare the trabecular structures of bones kept in different conditions

Preliminary results from push-and-release tests of a base-isolated building in Camerino, Italy

Experimental testing of a two-storey steel braced-frame building structure on a reinforced concrete slab isolated from the foundations resting on a steep slope through a hybrid system (high-damping rubber bearings and low-friction sliding bearings) is presented. The base-isolated building incorporates a permanent push-and-release device capable of displacement amplitudes as those induced by extreme seismic events and allowing the push-and-release tests to be repeated in the future. The tested building as well as its testing set up, whose cost represents a small increment of its construction cost if planned in the early stages of the design process, are presented. Afterwards, preliminary results from quasi-static push tests (slow loading and unloading) and push-and-release dynamic tests (slow loading and subsequent sudden release) are briefly described. Compared to push-and-release tests documented in the past, the activities presented in this article have peculiarities related to the building (typology, size, and foundation geometry), the magnitude of the maximum horizontal displacement achieved (284.6 mm), the possibility to repeat the same tests in the future, producing comprehensive sets of data for the analysis of the behaviour of the hybrid isolation system and superstructure

Push-and-release tests of a steel building with hybrid base isolation

Experimental testing of a two-storey 5875 square meters steel braced-frame structure resting on a reinforced concrete slab isolated from the foundations through a hybrid system (28 high-damping rubber bearings and 36 low-friction sliding bearings) is presented. The building incorporates a push-and-release device to evaluate its actual global dynamic response up to displacement amplitudes induced by extreme seismic events, allowing test repetitions during its service life. The testing set up and the experimental campaign, consisting of quasi-static push tests (slow loading and unloading) and push-and-release dynamic tests (slow loading and subsequent sudden release), are described. The experimental results have peculiarities related to the building (structural typology and size, foundation geometry on a steep slope, presence of the push-and-release device for future additional tests), the magnitude of the maximum horizontal displacement never achieved before (285 mm and 227 mm in the quasi-static and dynamic tests, respectively), the global and local monitored parameters (horizontal and vertical displacements, strains, accelerations, in addition to environmental conditions) providing a comprehensive insight into the behaviour of the hybrid isolation system and superstructure

Seismic Behaviour of an Innovative Hybrid Coupled Wall System Investigated Through Cyclic Tests

This article presents the experimental results obtained from the cyclic testing of an innovative hybrid coupled wall (HCW) system – a fixed-base reinforced concrete (RC) wall coupled with two steel side-columns via steel coupling links, where the wall carries almost all the horizontal shear force and the overturning moments are partially resisted by an axial tension-compression couple developed by the two steel columns rather than by the individual flexural action of the wall alone. The initial stiffness properties were primarily identified through the first cycle, estimating the yield force and displacement of the HCW system. Incremental cyclic tests were then conducted according to the ECCS 1986 provisions, targeting specific performance levels: (i) “reparability” of the HCW, i.e. the yield displacement, where the steel links yield with negligible damages in the wall and the self-centering capacity of the system is active, so that the actual replacement capacity of the elements can be validated; and (ii) a displacement level corresponding to a major earthquake with very low probability, which activates the wall as an additional dissipative element, eventually leading to a non-reparable damage state. Relevant results have been discussed through graphical and real-life illustrations. Finally, the constructional aspects are also discussed from a real-life application viewpoint

International Journal of Electronic Marketing and Retailing

The world of electronic marketing is continuously evolving. Marketing theories and practices must adapt to these new technological and social scenarios. IJEMR addresses this evolution by analysing new theories and practices as they emerge with particular focus on electronic retailing. Current technological and quantitative approaches to e-marketing, treating consumer relations as a database problem, are insufficient for a deeper understanding of the implications of this evolution. IJEMR fills this gap, fostering new cutting-edge approaches to e-marketing, e-consumers and e-tailing