Search results for "Joints"
showing 10 items of 147 documents
Joint image and motion reconstruction for PET using a B-spline motion model.
2012
We present a novel joint image and motion reconstruction method for PET. The method is based on gated data and reconstructs an image together with a motion function. The motion function can be used to transform the reconstructed image to any of the input gates. All available events (from all gates) are used in the reconstruction. The presented method uses a B-spline motion model, together with a novel motion regularization procedure that does not need a regularization parameter (which is usually extremely difficult to adjust). Several image and motion grid levels are used in order to reduce the reconstruction time. In a simulation study, the presented method is compared to a recently propos…
Anatomia clinica del sistema articolare del piede
2006
From a semantic point of view the word “ankle” and “ankle region” are not synonyms as “ankle” identifies all the components of the ankle joint while “ankle region” identifies the ankle joint as well as every structures in the region, form the surface level to the skeletal one. The articular system of the foot is formed by thirthyfour synovial joints, seventeen of which have complementary curvilinear articular surface, the remaning seventeen having plane joints. The rounded surface joints are: the talonavicular joint (a spheroidal joint that is part of the transverse tarsal joint), the “anatomical” subtalar joint ( a saddle joint), five ellipsoid (or condylar) joints and ten, ankle and inter…
Laser surface treatments for adhesion improvements of alluminium alloys structural joints
2006
Comportamento flessionale di nodi esterni in calcestruzzo fibrorinforzato
2010
A softened strut-and-tie macro model able to reproduce the flexural behavior of external beam-tocolumn joints with the presence of horizontal and vertical steel bars, including softening of compressed struts and yielding of main and secondary steel bars, is presented, to be used for the pushover analysis. The model proposed is able to calculate also the flexural response of fibrous reinforced concrete (FRC) beam-to-column sub-assemblages in term of a multilinear load-deflection curves. The model is able to take into account of the tensile behavior of main bars embedded in the surrounding concrete and of the softening of the compressed strut, the arrangement and percentage of the steel bars,…
Experimental characterization of friction properties of materials for innovative beam-to-column dissipative connection for low-damage RC structures
2023
Low-damage design of structures in seismic-prone areas is becoming an efficient strategy to obtain "earthquake-proof" buildings, i.e. buildings that, even in the case of severe seismic actions, experience a low or negligible amount of damage. Besides the safeguard of human lives, this design strategy aims also to limit the downtime of buildings, which represents a significant source of economic loss, and to ensure an immediate occupancy in the aftermath of an earthquake. In this context, focusing on moment-resisting frames (MRFs), several solutions have been developed for the beam-to-column connections (BCCs) of steel and precast/prestressed concrete structures, but very few for cast-in-sit…
Indagine sperimentale su nodi di tralicci in acciaio di travi reticolari miste
2009
Results of experimental tests on welded joints of steel truss of encased composite steel-concrete beams are presented. The welding of the inclined web bars to top bars, both of steel type B450C, and to bottom steel plate, the latter made of S355 steel type, are tested. Two analytical expressions for prediction of welding strength are derived: the one based on a resistance criterion and the other based on a limit domain of the welding section. Guidelines for choosing the effective dimensions of the fillet weld, necessary to determine the strength, are provided. A high precision digital scanner is used to validate the suggested guidelines to determine the geometrical characteristics of the fi…
Innovative connections for steel-concrete-trussed beams: a patented solution
2023
The most recent design strategies welcome the adoption of innovative techniques for seismic energy input mitigation, aiming to achieve high dissipation capacity, prevent the structure from collapse and ensure the serviceability of the construction. Friction damper devices have been widely adopted in framed steel structures for decades, while their introduction in different structural types is still under investigation. This paper presents the outcomes of innovative research supported by the industry and conducted on beam-to-column connections of RC structures in which the beams are Hybrid Steel-Trussed Concrete Beams (HSTCBs) and the columns are classical RC pillars. An innovative solution,…
Simplified equivalent finite element modelling of concrete-filled steel tubular K-joints with and without studs
2022
Concrete Filled Steel Tubular (CFST) K-joints employed for truss structures gained high interest in the last years due to their widespread use in engineering practice. The overall performances of these joints can be efficiently improved by using steel studs welded in the inner surface of the steel chord filled with the concrete, avoiding punching shear failure, and improving the overall strength and ductility. However, a reliable prediction of the structural behavior of the joints is outmost of importance for the assessment of the capacity of new and existing structures, and there are no standardized design methods nowadays. In this paper, the structural performances of CFST K-joints with a…
Seismic response of RC frames with HSTC beams endowed with friction damper devices
2019
The aim of this work is to compare the seismic response of RC frames built using Hybrid Steel-Trussed Concrete Beams (HSTCBs) whether or not equipped with friction damper devices installed at the beam-to-column joints. Due to their small depth-to-span ratios, HSTCBs usually lead to a large amount of rebar within the beam-column joint, potentially reducing its cyclic performance. Therefore, the adoption of a friction system at the beam-tocolumn joint provides two main advantages, i.e. limiting the shear forces, and thus the potential damage, in the panel zone thanks to the increasing of the bending moment lever arm, and assigning to the device the task of dissipating the incoming seismic ene…