The behaviour of reinforced concrete beam‐column (RCBC) joints may have an important influence on the structural behaviour of unbraced framed structures—this explains why current technical specifications require accounting for their deformation. However, the available numerical models for RCBC joints are rather complex, so that, at the end of the day, these joints are commonly modeled using one of two alternative simplified models: the rigid joint model and the centerline joint model. This calls for the development of “Simplified Classification Criteria”, which are simplified procedures to assess the influence of RCBC joints on the structural behaviour, that is, to determine whether a simplified joint model can be employed in the numerical model of the overall structure without leading to major errors in the analysis. This paper focuses on the possibility of using the rigid joint model. As a starting point for the step‐by‐step development of general classification criteria for RCBC joints we employ the basic simplified classification criterion already existing for steel beam‐column joints.

A reinforced concrete (RC) beam-column (RCBC) joint model for the quasi-static monotonic analysis of cast in situ RC frames is developed and implemented in a finite element analysis program for framed structures. The joint model was developed in the framework of the component method, a method originally developed for steel joints, which consists of three steps: (a) identification of the joint relevant basic components, their interaction, and contribution to overall joint behavior; (b) characterization of the mechanical behavior of each component; and (c) assembling of the components. With regard to the model implementation, the material nonlinear analysis is performed by the fictitious forces method-all the required steps are presented and explained-while the P-Δ method for the geometrical nonlinear analysis of frames is extended to include the beam-column joint model. The paper closes with illustrative and validation examples; while some of these are fully analytical, the others simulate lab-tested subframes subjected to quasi-static monotonic loads.

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The so-called 3-factor formula is one of the most commonly employed general formulae to estimate the elastic critical moment of steel beams prone to lateral-torsional buckling. This work extends its domain of application to I-section cantilevers (i) with equal or unequal flanges, (ii) fully built-in or free to warp at the support and (iii) acted on by uniformly distributed or concentrated tip loads (applied either at the shear centre or at one of the flanges). The paper includes (i) a discussion of the theoretical basis of elastic lateral-torsional buckling, (ii) the description of the main steps involved in posing the buckling problem in a non-dimensional form over a fixed reference domain, features that are particularly convenient for the purpose of this work, (iii) the numerical results of a parametric study, obtained by the Rayleigh-Ritz method, and (iv) their use for the development of approximate analytical expressions for the C 1 , C 2 and C 3 factors appearing in the aforementioned formula.

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Non-destructive testing (NDT) techniques play an important role in the characterization and diagnosis of historic buildings, keeping in mind their conservation and possible rehabilitation. This paper presents a new approach that merges building information modeling (BIM) with environment geospatial data obtained by several non-destructive techniques, namely terrestrial laser scanning, ground-penetrating radar, infrared thermography, and the automatic classification of pathologies based on RGB (red, green, blue) imaging acquired with an unmanned aircraft system (UAS). This approach was applied to the inspection of the Monastery of Batalha in Leiria, Portugal, a UNESCO World Heritage Site. To assess the capabilities of each technique, different parts of the monastery were examined, namely (i) part of its west façade, including a few protruding buttresses, and (ii) the masonry vaults of the Church (nave, right-hand aisle, and transept) and the Founder’s Chapel. After describing the employed techniques, a discussion of the optimization, treatment and integration of the acquired data through the BIM approach is presented. This work intends to contribute to the application of BIM in the field of cultural heritage, aiming at its future use in different activities such as facility management, support in the restoration and rehabilitation process, and research.

SUMMARYA simple non-linear mechanical system comprising a pin-jointed string of ÿnite-length links, supported by elastic springs at the pins and compressed by an axial load, is viewed from two perspectives. When seen as an initial-value problem, equilibrium equations provide an iterative non-linear mapping. When seen as a boundary-value problem, it becomes a simple ÿnite element model. At loads less than the critical buckling load, a preferred buckling conÿguration is found that is localized along the length. In the limit of inÿnite length this is described as a homoclinic connection in phase space, joining the at equilibrium state to itself. The inÿnite sequence of homoclinic points thus deÿned embeds within the complex topological structure of a homoclinic tangle, within which also appear periodic, quasi-periodic, and chaotic spatial solutions. Implications in the ÿnite element setting are discussed. ? 1997 by John Wiley & Sons, Ltd.