1,721,023 research outputs found
Strongback system to enhance the building seismic response of framed structures
No full textIn the present paper the behavior of a special structural system is investigated: the innovative system is
composed of a vertical elastic truss, known in the literature as strongback, which acts as a mast when coupled with
frame structures by imposing to the latter one a given lateral deformed shape. The rigid behavior of the strongback,
designed to remain in the elastic field under strong seismic ground motion, imposes a uniform inter-storey drift
along the frame height, thus avoiding undesired effects such as soft-storey and weak-storey mechanisms.
Therefore, the combined structural systems can be modelled at first approximation as an equivalent Single
Degree of Freedom system, thus allowing for a simple analytical description of its response.
In particular, in the present work the attention is mainly focused on the mutual actions exchanged by the
strongback and the frame, through infinitely rigid connections at each floor. Assuming a shear-type behavior of the
frame, an analytical solution of the static equilibrium equations is found. Finally, some numerical simulations of
the seismic response of the frame systems with strongback systems are developed, both considering shear-type
frames and frames with flexible beams
Toward “Strength-Based” Wall Structures for Seismic-Proof Buildings
No full textThe behavior of “ductile seismic frames”,
which is strongly related upon construction details and
specific design rules, during strong earthquake appears
to be often not in agreement with average expectations
of modern societies which consider not admissible
human lives losses and building collapses. The issue of
safe constructions against natural hazards appears even
more important for those essential facilities, such as
hospitals and schools whose collapse could provoke
dramatic consequences. In the present paper, a brief
history of construction from the appearance of first
framed structures to wall-based and tubular structures
for tall buildings and to the more recent construction
technologies for low-rise buildings using insulating
concrete forms and sandwich panels, is provided within
Earthquake Engineering perspectives. It is shown as the
use of “tubular” structures for low-rise buildings (such
as residential buildings) realized with modern
construction technologies would ensure the achievement
of quite superior structural performances, especially
with respect to seismic induced actions
PALO RETICOLARE E RELATIVA STRUTTURA ROMBOIDALE
No full textPalo reticolare innovativo con struttura romboidale, formato
da facce laterali interconnesse che proiettano una forma
poligonale. Il palo, sviluppato verticalmente con elementi
reticolari romboidali connessi, è realizzato utilizzando la
tecnologia WAAM (Wire and Arc Additive Manufacturing) di
tipo “dot-by-dot” o “point-by-point”
Stima del rapporto di smorzamento per strutture a telaio con sistemi dissipativi mediante riduzione a sistema equivalente a singolo grado di libertà
No full textA bracing system for optimized seismic performance of multistory frame structures
No full textThe proposed work presents the seismic
performances of a structural system obtained by
connecting a moment-resisting frame structure with a
vertical elastic truss, known in the literature as
strongback. The strongback system is able to limit the
development of excessive inter-storey drifts thus
reducing potential dangerous phenomena such as
weak/soft stories. In addition, the strongback system can
be equipped with viscous dampers enhancing energy
dissipation properties of the whole structure. In the
present paper, an applicative example is developed in
order to compare the effectiveness of both the
strongback system and different dampers placements
Un metodo semplificato per il dimensionamento e l’analisi di strutture equipaggiate con smorzatori viscosi A simplified method for dimensioning and analyzing equipped structures with viscous dampers
No full textLa presente memoria presenta un metodo diretto per il dimensionamento di strutture a telaio dotate di smorzatori viscosi che
permette: (1) di dimensionare la taglia degli smorzatori viscosi da inserire nella struttura in modo da soddisfare un determinato
obiettivo prestazionale; (2) di stimare le massime sollecitazioni negli elementi strutturali attraverso l’inviluppo di due
analisi statiche equivalenti
A multi-performance seismic design procedure to incorporate Crescent Shaped Braces in mid-rise frame structures
Full text linkThis paper introduces a novel procedure for the seismic design of a new class of seismic-resisting systems for mid-rise buildings obtained by incorporating special yielding steel braces known as Crescent Shaped Braces (CSBs) into Not Moment-Resisting Frames (NMRFs). The proposed design procedure is grounded on the Performance- Based Seismic Design (PBSD) framework through the imposition of multiple seismic performance objectives with the aim of obtaining an almost uniform along-the-height seismic behavior. The desired uniform seismic behavior is ensured by imposing: (i) uniform inter-storey drifts under frequent earthquakes; (ii) widespread yielding of the braces along the building height under occasional earthquakes; (iii) minimum ductility capacity at all storeys to be exploited under rare earthquakes; (iv) minimum hardening stiffness for the mitigation of the second order (P-Δ) effects under very rare earthquakes. The desired performances are made possible by the specific features of the CSBs in terms of initial lateral stiffness, yielding strength, ductility capacity and final hardening response. The procedure is articulated in four conceptual phases and several steps to guide the professional engineer through all the main design phases, from the selection of the seismic performance objectives to the preliminary sizing of the CSB devices, up to the final design/verification through non-linear time-history analyses. The effectiveness of the proposed design procedure is finally demonstrated through an applicative example
Frontiers in Built Environment Construction Materials
No full textFrontiers in Built Environment is a multidisciplinary journal that focuses on the development of smart and sustainable methodologies for the design, construction and management of resilient buildings and infrastructure
Palo reticolare
No full textL’innovazione consiste nella progettazione di un palo reticolare innovativo realizzato mediante tecnologia di stampa 3D. Il palo ha una sezione tubolare “atomizzata”, che forma una superficie esterna di tipo reticolare (“lattice structure”) costituita da elementi rettilinei continui. La continuità degli elementi rettilinei costituenti la struttura reticolare è garantita grazie alla tecnologia di realizzazione di tipo additivo per metalli di tipo Wire-and-Arc Additive Manufacturing, che supera la connessione di più elementi nella realizzazione di un unico elemento tubolare di tipo reticolare. L’innovazione si può estendere a una pluralità di forme (sezione di larghezza costante o variabile in altezza) e applicazioni a seconda della destinazione d’uso.
Il palo reticolare garantisce prestazioni di resistenza confrontabili con il palo tradizionale, a fronte di un abbattimento del materiale impiegato (fino al 90% di risparmio di materiale), fornendo così anche un ridotto impatto ambientale
Coupled response of framed structures connected to strongback
No full textIn the present paper, the coupled behavior of structural systems obtained by connecting a moment resisting frame structure with a
vertical elastic truss, known in the literature as strongback, which acts as a mast by imposing to the structure a given lateral deformed shape, is
investigated. The rigid behavior of the strongback, which has to be designed to remain in the elastic field under strong seismic ground motion,
linearizes the lateral displacement profile of the adjacent frame through an exchange of mutual horizontal actions. The presence of the
strongback should thus help in limiting undesired effects, such as soft-story and weak-story mechanisms. For the proper design of both
the truss system forming the strongback and the frame members, the preliminary evaluation of the actions exchanged between the systems
is of fundamental importance. The aim of the work is to develop analytical formulas for estimating mutual actions and internal actions in
the frame members for the limiting cases of shear-type frames and pendulum-type frames. Finally, some numerical simulations of frame
systems with strongback systems as subjected to earthquake ground motions are developed, including the cases of frames with flexible beams.
It is found that the amplitudes and distributions of both mutual actions and internal actions in the frame are significantly affected by the beamto-
column stiffness ratio. In the case of relatively stiff beams, the mutual actions tend to reduce the shear and bending moment at the lower
stories, which are rather uniformly redistributed along the height. On the contrary, in the case of relatively flexible beams, large mutual actions
and internal actions (shear and bending moments) are concentrated at the lower stories, with the upper stories remaining practically unloaded
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