33,691 research outputs found
Mechanical characterization of timber in structural sizes: bending and compression tests
This paper presents the results obtained in a series of tests on Pinus Pinaster Ait. timber specimens, using the prEN408:2000, to estimate the local and global Young’s modulus and strength both in bending and compression parallel to the grain. The results obtained are compared with the values presented in the Portuguese Nationally Determined Parameters of Eurocode 5, for the quality classes assign by Portuguese Standard NP4305:1994 by visual grading
Behaviour of traditional Portuguese timber roof structures
The aim of this paper is to present the results of a structural analysis of common trusses traditionally used in roof construction in Portugal. The study includes the results of a preliminary survey intending to assess the geometry, materials and on site pathologies, as well as a twodimensional linear elastic static and dynamic analysis. The trusses behaviour under symmetric and non-symmetric loads, the king post/tie-beam connection, the stiffness of the joints and the incorrect positioning of the purlins, were some of the structural aspects that have been investigated
Modelling of timber joints in traditional structures
Original unstrengthened timber connections and the effects of different strengthening techniques
have been evaluated experimentally with tests on full-scale birdsmouth joints. Experimental results
show that structural response of traditional timber connections under cyclic loading cannot be
represented by common constraint models, like perfect hinges or rigid joints, but should be using
semi-rigid and friction based models. A research program has investigated the behaviour of old
timber joints and examined strengthening criteria. The main parameters affecting the mechanical
behaviour of the connection have been singled out. A synthetic model of cyclic behaviour has been
adapted on the basis of experimental results
Experimental analysis of original and strengthened traditional timber connections
Tests on full-scale unstrengthened connections were performed under monotonic and cyclic loading. Attention has been principally focused on the birdsmouth joint, because of its common use in practice. Different strengthening solutions with metal elements have been evaluated
Bayesian model selection for electromagnetic kaon production on the nucleon
We present the results of a Bayesian analysis of a Regge model to describe
the background contribution for K+ Lambda and K+ Sigma0 photoproduction. The
model is based on the exchange of K+(494) and K*+(892) trajectories in the
t-channel. We utilise the Bayesian evidence Z to determine the best model
variant for each channel. The Bayesian evidence integrals were calculated using
the Nested Sampling algorithm. For different prior widths, we find decisive
Bayesian evidence (\Delta ln Z ~ 24) for a K+ Lambda photoproduction Regge
model with a positive vector coupling and a negative tensor coupling constant
for the K*+(892) trajectory, and a rotating phase factor for both trajectories.
Using the chi^2 minimisation method, one could not draw this conclusion from
the same dataset. For the K+ Sigma0 photoproduction Regge model, on the other
hand, the difference between the evidence integrals is insufficient to pinpoint
one model variant.Comment: 13 pages, 4 figure
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