1,721,177 research outputs found
Evaluation of shrinkage effects in steel-concrete composite beams with deformable connection
No full textEvaluation of creep and shrinkage effects in steel-concrete composite beams with rigid or deformable connection using a simplified approach based on the AAEM method
No full textInfluence of connection properties on evaluation of short- and long-term effects for steel-concrete composite beams under service loading
No full textAnalysis of rigid and semi-rigid steel-concrete composite joints under monotonic loading. Part II: parametric study and comparison with the Eurocode 4 proposal
No full textThis paper analyses the response of rigid and semi-rigid steel-concrete composite joints under monotonic loading. The influence of some important parameters, such as the presence of column web
stiffening and the mechanical properties of component materials, is investigated by using a three-dimensional
finite element modelling based on the Abaqus code. Numerical and experimental responses of different types
of composite joints are also compared with the analytical results obtained using the component approach proposed by Eurocode 4. The results obtained with this approach generally fit well with the numerical and experimental values in terms of strength. Conversely, some significant limits arise when evaluating initial stiffness and non-linear behaviour of the composite joint
A finite element model for the study of creep and shrinkage effects in composite beams with deformable shear connections
No full textA macroelement for the cyclic analysis of masonry structures
No full textIn this work, a macroelement for the cyclic analysis of masonry structures is presented. The proposed model is based on the equivalent frame method to represent the structure, in which each masonry pier or spandrel is schematised by a beam-type macroelement containing two flexural nonlinear springs at both ends, a shear nonlinear spring in the middle and two Euler-Bernoulli elastic beams connecting them. Each springs have a length conventionally chosen by the user in percentage of the macroelement height, and their characteristics are calculated automatically. The springs exhibit a cyclic behaviour, different for flexure and shear. Stiffness and strength degradation are implemented in both hysteretic laws; moreover, the strength is calculated during the analysis as a function of the axial compressive load. All parameters governing degradations and hysteretic cycles are obtained on the base of the results of experimental tests on masonry piers.
The macroelement, implemented as User Element (UEL) in the general FE code Abaqus is formulated using the static condensation method, and it supplies the tangent stiffness matrix and the force vector as output. The force vector is obtained assembling the contribution of each element and performing some simple Newton-Raphson iterations to ensure the internal equilibrium.
To validate the proposed cyclic behaviour, two cyclic experimental tests on masonry piers have been reproduced numerically. It is shown that the macroelement is able to change the amount of dissipated energy on the base of the slenderness of the masonry wall thanks to the stiffness ratios of the non-linear springs. For a slender pier, which mostly has a flexural collapse, the rotational springs will mainly influence the whole response, while for a squat wall, that presents a shear failure, the shear spring will be more stressed.
A comparison between experimental and numerical results is also performed on a 2-storey perforated façade subjected to a cyclic test, evidencing the validity of the presented approach in real models
Analysis of rigid and semi-rigid steel-concrete composite joints under monotonic loading. Part I: finite element modelling and validation
No full textThe paper concerns the modelling of rigid and semi-rigid steel-concrete composite joints under
monotonic loading through use of the Abaqus program, a widespread finite element code. By comparing numerical and experimental results obtained on cruciform tests, it is shown that the proposed modelling allows a good fit of the global joint response in terms of moment-rotation law. Even the local response in terms of stresses and strains is adequately predicted. Hence, this numerical approach may represent a useful tool for attaining a better understanding of experimental results. It may also be used to perform parametric
analyses and to calibrate simplified mechanical models for practical applications
Effective width evaluation for steel-concrete composite beams
No full textIn this paper the problems connected to the effective width evaluation for serviceability and ultimate analysis of steel–concrete composite beams are analyzed. By a parametric study carried
out through the Abaqus code it is pointed out how the actual codes do not provide, in general appropriate results, for elastic and ultimate limit state checks. The most important parameters that influence the effective width are analyzed. Some preliminary criteria for an
adequate design are presented
Simplified approach to evaluate creep and shrinkage effects in steel-concrete composite beams
No full textA simplified approach to evaluate creep and shrinkage effects in a steel-concrete composite beam with rigid or deformable connections, based on the age-adjusted effective modulus method, is presented. An aging coefficient, χ, evaluated in the absence of connection is adopted and exactly characterized by a theoretical point of view. Simplified expressions to evaluate χ and an easy to use, closed-form solution in the hypothesis of rigid connections and uncracked concrete are proposed. Numerical comparisons show how the proposed approach provides accurate results independently of the connection stiffness and load condition, and how it can substitute appropriately the more popular effective modulus method
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