1,720,989 research outputs found
Openings in infills with horizontal sliding joints: a parametric study to support the design
No full textOn the Nature of the Hydrated Layer and of Strong Lewis Acidic Centres at the Surface of Pure and Sulphate-Doped Anatase
No full textInfill with sliding panels in presence of a full-height opening: Experimental in-plane response
No full textINFILL 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
PBEE ASSESSMENT OF RC FRAMES WITH TRADITIONAL AND SLIDING-JOINT INFILLS
No full textIn reinforced concrete (RC) multi-storey buildings, the important role of the seismic interaction of structural frames with masonry infills has been revealed by several earthquakes and
investigated by many authors. Recently, several innovative infill solutions have been proposed
to mitigate such interaction, which could result in widespread damage in both the masonry
and the RC structure and sometimes jeopardize the building stability and the occupants’ safety. One solution consists in the partitioning of the masonry infill into several sub-panels, relatively sliding along specific joints. This paper investigates the seismic performance
assessment of this technological solution in the framework of performance base earthquake
engineering. A two-dimensional five-storey RC seismic-resistant frame is selected as case
study and the performance is assessed by comparing the responses of the same structure infilled with different solutions, made of sliding joints or traditional masonry, or in the bare configuration. Incremental Dynamic Analyses (IDA) is used for the probabilistic determination of fragility curves of the structures. Results show the seismic fragility and reliability of the different investigated structures, especially addressing the probabilities of occurrence of
damage at different limit states and quantifying the associated expected annual loss
Experimental assessment of an innovative isolation technique for the seismic downgrade of existing masonry infills
No full textThe seismic vulnerability of infilled reinforced concrete (RC) frames built in the Mediterranean earthquake prone regions before the 70’s has been assessed by many post-earthquake surveys and several experimental studies. Beyond the lack of seismic-resistant detailing in the frame elements, a relevant source of vulnerability for these structural typology is represented by the in-plane interaction between the frame and the infills. Infills are typically made of masonry, selected for its good thermal and acoustic insulation performance and characterized by high stiffness and strength, but coupled with a brittle post-peak behavior. During an earthquake, the different stiffness and deformation capacity characterizing the infill and the frame can lead to severe damage, including widespread cracking and crushing in the former, and brittle shear failures in the latter. When dealing with the seismic retrofit of an existing infilled RC building, this local interaction cannot be ignored, as it could jeopardize the efficiency of the seismic retrofit intervention by triggering unexpected early collapses in the existing frame. In order to mitigate this issue, in the present paper an infill isolation technique is presented, conceived to reduce the infill-frame in-plane interaction (downgrade). The downgrade is obtained by isolating the infill from the surrounding frame with a cut on a portion of the infill perimeter. A specific innovative wall-to-frame beam connection is implemented, which promotes the masonry arching mechanism against out-of-plane actions, while ensuring in-plane relative sliding. In the paper, the experimental cyclic in-plane and out-of-plane response of a real scale specimen downgraded with the proposed technique are presented and some issues about the conceptual design of the intervention and its invasiveness are discussed
Seismic reliability and loss assessment of RC frame structures with traditional and innovative masonry infills
No full textThis paper presents a performance-based earthquake engineering framework aimed at the assessment of fragility, reliability and expected annual loss (EAL) of reinforced concrete (RC) frames with traditional infills (TI) and innovative infills with sliding joints (SJ). The main concern is first related to the modification of seismic reliability levels achievable for structural and non-structural limit states by code conforming RC structures when explicitly considering the influence of masonry infills and the quantification of the gain associated with the eventual use of sliding-joint infills (SJI). Further, expected annual losses within the service life are evaluated and compared for the considered structural typologies. The framework is based on the determination of fragility via incremental dynamic analysis (IDA) in order to consider statistical response to input variability. The analyses are carried out on a reference multi-storey multi-bay 2D structure modeled in OpenSEES using a fiber-section approach. Specific structural and non-structural limit states are individuated for the TI and SJI frame structures. Seismic reliability is evaluated by integrating site hazard and structural fragilities resulting for each limit state. Expected annual loss assessment is performed by directly using period dependent hazard curves to determine annual rates of failures associated with limit states. Results show that similar probabilities of exceedance and loss rates are obtained by traditional infill and sliding-joint infill structures at life safety and collapse limit states. On the contrary significant convenience in using SJI is observed for operational and damage limit states in terms of reduced probability of occurrence and EAL
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
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