Desde los inicios del análisis estructural de las estructuras de mampostería, se ha perseguido conocer su comportamiento teniendo en cuenta la influencia de los distintos elementos que lo conforman, evolucionando el análisis estructural de los arcos de fábrica hasta analizar el comportamiento fracto-mecánico de la mampostería. Este artículo presenta la adaptación del criterio de falla de Tsai- Hill para materiales ortótropos, aplicado al estudio de los arcos de mampostería. Ello se ha llevado acabo la adaptación en una subrutina VUSFLD de ABAQUS en lenguaje de programación Fortran. Esta subrutina se ha validado en atención a la falla del mortero, y se ha analizado el efecto del mortero en el análisis de un arco de mampostería. La subrutina implementada en un masomodelo permite observar la contribución del mismo a la capacidad portante de un arco.

The development of accurate structural modelling techniques is required to promote the use of timber as a renewable alternative to other structural materials. Due to their remarkable influence on the global behaviour of a timber structure, an accurate description of the performance of structural connections is needed. Particularly in the case of moment transmitting beam-to-column connections with dowel-type fasteners, such properties are difficult to obtain experimentally. This paper develops a finite element (FE) model that simulates the behaviour of these connections under quasi-static loading, with a focus on the estimation of rotational stiffness and load distribution among the dowels. The model is validated against short-term laboratory tests. Resulting friction between timber members due to the installation procedure must be considered, as it greatly influences the rotational response. Besides, non-linear behaviour of timber and a softened contact parameter have been implemented, and their influence on the FE model validation process is demonstrated.

The accurate simulation of steel structures requires a precise model of the joint behaviour. The methods proposed by the steel codes are based on either rotating springs or involved models of springs and rigid bars. In this article, a precise method to model the stiffness of 2D bolted steel connections is presented. First, the joint is accurately modelled using finite elements (FE). Then, the FE model is condensed to a cruciform element of 4 nodes (12 degrees of freedom) by constraining each side cross-section to a node located at its centre of gravity. Subsequently, forces are applied to each node to compute the flexibility matrix, which is then used to construct the stiffness matrix that is finally decomposed through singular value factorization. Following this procedure, a parametric study is conducted to build the training and validation sets of the metamodel. Kriging and Radial Basis Functions are chosen to metamodel and predict the stiffness matrices of the cases not included in the parametric study. Finally, steel structures are analysed with both complete finite elements and surrogate models, and the results are used to confirm the accuracy of the proposed method.

Torsional effects in joints need to be investigated in order to get a complete model of the joint and also to assess the real boundary conditions for the lateral torsional effects in the beams of structural frames. Phenomena such as: torsion, warping, lateral buckling, etc. are usually analysed assuming simplified boundary conditions, namely pinned or rigid, in frame analysis which can lead to erroneous and non-conservative results. With the aim of knowing the correct boundary conditions and real behaviour of the joints under torsion, an experimental program is carried out consisting of two tests of mayor axis doubled extended bolted end plate joints subjected to torsion about the axis along the length of the beam. These experimental results have allowed the validation of the finite element models carried out using the program Abaqus. Once the models are validated models, a parametric study is performed to assess the stiffness and resistance. This study also verifies that these joints behave in a semi-rigid way when compared with the torsional characteristics of the attached beam. Besides, the beam fails prior to the connection in most cases, and therefore, the joints can be assumed to behave as full-strength. Analytical expressions are proposed and checked with the FEM results proving that the proposed analytical formulae and the proposed mechanical model can predict the stiffness quite accurately, with an average error of 8.5%. Despite these joints can be classified as full-strength under torsion, an assessment of their resistance is done as well.

Beam to column connections subjected to loads in the beam minor axis direction are usually considered either as pinned or rigid for both resistance and stiffness checks. However, modern codes contemplate the possibility of semi-rigid and partial strength connections. The Eurocode 3 provides criteria, based on the component method, to characterise such connections. There are unresolved issues regarding three-dimensional connections and connections subjected to out-of-plane effects that need further research. Their behaviour relies mainly on the characterisation of the components acting on the T-stub under out-of-plane bending, and this characterisation is the aim of this paper. An experimental program consisting of five T-stub tests has been carried out and finite element models have been developed. The finite element models have been validated with the experimental results and prove to be an accurate tool for the characterisation of 3D connections. The connection characteristics have been obtained by means of tests and finite element models, and after comparison with the limits provided by the Eurocode 3, it is concluded that all connections under study are indeed semi-rigid and partial strength.

Semi-rigid composite joints not only have the advantage of optimizing the use of the material, but also of providing lateral stiffness for sway frames. By means of semi-rigid joints, the lateral stability of the structure may rely on the stiffness and ductility of the joints, thus avoiding bracing systems. These advantages may even increase when the joints are designed as semi-rigid in both axes. In this case, the joint behaves in a three-dimensional way that includes an interaction between the major and the minor axis of the column. In this paper, a new design for three-dimensional semi-rigid composite joint is proposed and tested in order to improve the behaviour and obtain the benefits of semi-rigidity when both the major and minor axis are included. Thus, the proposed design involves beams that are attached in a semi-rigid manner to both, the major and minor axes of the column. The experimental program consists in one 3D semi-rigid composite internal joint under proportional loads, another internal joint subjected to non-proportional loads and one facade joint. These tests provide information as to whether the joints satisfy the requirements of the Eurocodes 3 and 4 (EC3 and EC4) in terms of ductility, stiffness and resistance. Also the possible interactions between the major and minor axes of the proposed joint that are caused by the loads and/or the geometry are studied. Simultaneously, finite element modelling and analysis have been carried out and calibrated agains

This paper deals with a component-based approach to model internal and external semirigid composite connections for the global analysis of frames. The method is based on a cruciform finite sized elastic-plastic joint element that takes into consideration its deformation characteristics including those of the panel zone as well as the left and right connections. In addition, all the internal forces that concur at the joint coming from the beams and columns and their respective eccentricities are also considered.