196,202 research outputs found
INFILL WITH SLIDING PANELS AND A FULL-HEIGHT OPENING
No full textThe innovative infill construction technique for seismic resistance, implementing horizontal
sliding joints to partition the wall into subpanels, it is here tested in presence of a full height
opening. With the double aim of protecting the opening fixtures (window or door) from the infill
sub-panels’ relative sliding and offer out of plane support to the infill, a post is placed at the
opening side spanning between the top and bottom beam of the frame. The post stiffness and
strength design is the object of the study. The role of the post deformability was studied by
modifying the post’s stiffness with additional steel profiles coupled to the initial wooden post
configuration, in different test phases. The shear action at the post ends was measured with
specific load cells, to provide information for the proportioning of the post and its connection
to the beams. The results showed the efficiency of the post in governing the sliding mechanism
between the infill sub-portions and the role of the post’s stiffness in modifying the in-plane
response of the infill. Thanks to the post’s deformability, the overall infill-frame interaction was
reduced with respect to previously tested similar infills without openings
Ambient vibration testing of the Paderno iron bridge (1889)
No full textThe bridge over the Adda river at Paderno, opened in 1889, is one of the most important monuments of 19th century iron architecture. Notwithstanding the lack of maintenance and the poor state of preservation, the historic infrastructure is still used as a combined road and rail bridge. The paper focuses on the ambient vibration modal testing and analysis, performed on the bridge between June and October 2009, in order to address a Structural Health Monitoring program based on a continuous dynamic monitoring system
Infill with sliding panels in presence of a full-height opening: Experimental in-plane response
No full textExisting RC bare frames reinforced with smooth rebars: Influence of the modelling approach
No full textSeveral existing RC frame buildings were designed only for gravity loads and built with smooth rebars. Experimental results showed that the seismic behaviour of this kind of structures is different with respect to those built with deformed rebars; consequently, the classical modelling approaches are sometimes inadequate. The poor bond performance of smooth rebars provides high deformability to frame members that turns out to be an important resource for the seismic retrofit. In fact, the larger deformation capacity of the existing structure allows for more slender and flexible retrofit systems. A modelling approach to account for the smooth rebar slip contribution to the RC frame members overall deformability is presented and its results are compared to those of experimental tests available in the literature. Finally, an application to a bidimensional RC frame and its strengthening is discussed
Experimental Evaluation of the Cyclic Behaviour of Different Smooth Rebar Anchoring Layouts
No full textThe existing reinforced concrete frame structures built before the 1970s were designed only for gravity loads, and they were mainly built using smooth steel rebars. The behaviour of these kinds of structures is different with respect to that exhibited by structures reinforced with deformed rebars. Low bond capacity and the associated slip of the anchorages characterise a more flexible structural response and a lower energy dissipation of the elements. The contribution of rebar slip to structural deformability is often not considered in traditional lumped plasticity models used for the assessment of existing structures. An innovative modelling approach has been recently proposed to directly account for smooth rebar slip, so the characterization of the cyclic behaviour of different types of anchorages is of primary importance. A first experimental campaign was conducted on straight, hooked-end, and bent anchorages to evaluate their hysteretic behaviour and their strength capacity. Some aspects highlighted by the first campaign were investigated in the second one, the main results are here presented. The influence of the bond conditions and of the embedded length on the anchorage performance of plain rebars was investigated, and the mean bond strength was thus evaluated. Finally, the cyclic behaviour of bent anchorages for different bond conditions is analysed
Diagnostics and preservation strategies applied to historic iron infrastructures: the Paderno arch bridge (1889)
No full textThe paper summarizes the dynamics-based assessment of the historic San Michele bridge at Paderno d’Adda (Italy). The San Michele bridge over the Adda river at Paderno, built between 1887 and 1889, is one of the masterpieces of XIX century iron architecture and a symbol of Italian industrial archaeology heritage. In order to address a Structural Health Monitoring (SHM) program of the bridge - that is still used as a combined road and railway bridge -a series of dynamic test s was performed in operational conditions between June 2009 and June 2011 which drove to the installation of a permanent dynamic monitoring system. The whole investigation includes dynamic testing and long term monitoring, visual inspection and development of a baseline FE model of the historic bridge
Insediamento produttivo per quarantadue imprese artigiane a Paderno Dugnano, Milano
No full textPubblicato in: A. Bonardi, Dieci insediamenti artigiani promossi dalla CNA in provincia di Milano, in “Edilizia Popolare”, n. 172, maggio-giugno 1983;
E. Bordogna, Tendenze recenti nell’edilizia milanese, in “Controspazio”, n. 2-3, aprile-settembre 1984;
Aa. Vv., Alla ricerca dello spazio ottimale. Insediamento artigianale a Paderno Dugnano, a cura di A. Tosi, in “Il nuovo cantiere”, n. 4, aprile 1986;
Aa.Vv., Annali dell’architettura italiana contemporanea 1985, a cura di M. Casciato e G. Muratore, Officina, Roma 1986;
A. Bugatti, Come due isolati in mattoni, in “Costruire”, n. 55, ottobre 198
Analytical and numerical modelling of existing RC frames with smooth rebars
No full textThe work refers to the seismic behaviour of existing reinforced concrete (RC) frame buildings reinforced with plain rebar. A focus on the modelling of their flexural response is proposed, to explicitly consider the effect of smooth reinforcement slip on the structural performance. Analytical stress-slip relationships for different plain rebar anchorage shape are presented, their implementation in a structural model is then suggested. The element non-linear behaviour is lumped at the element end, based on its expected rocking-like behaviour; nevertheless, the model is able to account for the deformation contribution spread along the rebar embedded length, both in the element and in the joint or foundation side. The cyclic behaviour of an anchored plain rebar is also analytically treated; however, to facilitate the representation in a numerical environment, simplified rules are proposed to simulate the effects of reversal and repeated loading. The effectiveness of the model in predicting the response of such type of buildings is proved by simulating tests on columns, beam-column joints, and an entire frame, taken from literature. The structural elastic response is well captured, as well as the energy dissipation during cycling loading. The assessed secant stiffness at yielding is found to be significantly lower with respect to the prediction obtained without the consideration of smooth bar slip; in other words, with respect to the stiffness assessed for an element with deformed reinforcement. The results are particularly significant for range of drift demand within 1.50% and help a comprehensive design and assessment of seismic retrofit of existing buildings, since the modelling approach allow a reliable prediction of the triggering of brittle mechanisms
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