New simplified analytical method for the Prediction of global stability of steel and composite sway frames

peer reviewedEurocode 4 is the European design code for composite construction; in its so-called EN 1994-1-1 version, the design of “non-sway buildings” is mainly covered. As a result, EC4 focuses on the check of structural elements like beams, columns, slabs and joints. However, in the last years, the construction of taller buildings and larger industrial halls without wind bracing systems tends to make global instability a relevant failure mode, which is not well covered by Eurocode 4. Recently, intensive experimental, numerical and theoretical investigations have been carried out at Liège University. The latter aimed at improving the knowledge in the field of sway composite building frames and at developing appropriate design rules. The rotational behavior of the beam-to-column composite joints is one of the key aspects of the problem to which a special attention has been paid. This paper reflects investigations carried out at Liege University on this topic. In particular, an innovative simplified analytical method to predict the ultimate loading factor and the associated collapse mode of both steel and composite frames subjected to static loadings is presented

Evaluation of awake prone positioning effectiveness in moderate to severe COVID-19

Evidence mainly from high income countries suggests that lying in the prone position may be beneficial in patients with COVID-19 even if they are not receiving invasive ventilation. Studies indicate that increased duration of prone position may be associated with improved outcomes, but achieving this requires additional staff time and resources. Our study aims to support prolonged (≥ 8hours/day) awake prone positioning in patients with moderate to severe COVID-19 disease in Vietnam. We use a specialist team to support prone positioning of patients and wearable devices to assist monitoring vital signs and prone position and an electronic data registry to capture routine clinical data

Development of analytical models for the prediction of the elastic behaviour of joints with dowel fasteners in timber construction

A general procedure for the evaluation of the mechanical properties of structural joints, named “component method”, is now available from intensive research works at the European level. This procedure allows the analytical prediction of the resistance, but also of the stiffness and the deformation capacity, of structural joints under external forces (axial or shear forces, bending moments …). The component method is nowadays integrated as a reference procedure in two European de-sign codes, respectively for steel structures (EC3 [EN1993]) and steel-concrete composite structures (EC4 [EN1994]). However, its potential scope is much larger and present studies are aimed to apply to situations as joints in fire, joints under seismic loading, joints under exceptional loads (Robustness Project) …. More recently, a research project [CTI-2004] has succeeded in applying the component method to the investigation of the elastic behaviour of mechanical joints in timber construction. That is the result of the collaboration of CTIB-TCHN (Belgian Institute for Wood Technology) and University of Liège. The main principle of the component method is the following: • identification of constitutive components subjected to tension, compression or shear in the joint; • determination of the mechanical behaviour of these individual components; • "assembling" components so as to derive the mechanical properties of the whole joint. In the present paper, timber joints with dowel fasteners are considered. Two components may be identified: • "dowel" component (dowel fastener in bending and shear); • embedding component (timber member in embedding). The "dowel" component is known from past researches, whereas little information is available for the embedding component. EC5 [EN1995] proposes formulation to predict the behaviour for joints composed of these two components; but it only depends on two factors: the dowel diameter and the timber density. The influence probably significant of the grain direction (material strongly anisotropy) and the thickness of the connected members are for instance neglected. Experimental, numerical and analytical investigations have recently been performed by Uni-versity of Liège in collaboration with CTIB-TCHN so as to propose another formulation more precise for joints. Experimental results, performed by CTIB-TCHN, have been used as refer-ence for the development of numerical model and, then, analytical model. The application of the component method to the prediction of the elastic behaviour of timber joints consist of two steps: • "local" investigation on components that is to develop analytical models for the pre-diction of the elastic behaviour of components; • "global" investigation on joints that is to develop analytical models for the prediction of the elastic behaviour of joints. The application of the component method to timber joints with dowel fasteners is a first step towards the use of this concept in future to others mechanical joints (screw, punched metal plate, nail, bolt …). In this case, others components may be derived to cover the field of ap-plication expected

Numerical and analytical investigations on iron columns reinforced by FRP under axial compression

peer reviewe

Application of the component method to structural joints with dowel fasteners in timber construction

peer reviewe

Experimental and numerical investigations on iron columns reinforced by FRP under axial compression

peer reviewedThis paper presents experimental and numerical investigations on iron columns under axial compression, strengthened with high modulus carbon fibre reinforced polymer (FRP) sheets. It is shown that the resistance and stiffness of iron columns can be increased significantly with the use of longitudinal FRP sheets as a result of the reduction of the column slenderness, but also that transverse FRP sheets should be used to prevent any local buckling of the longitudinal FRP sheets

Proposed design rules for iron columns reinforced by FRP

peer reviewedThis paper presents design rules for iron columns under axial compression, strengthened with high modulus carbon fibre reinforced polymer (FRP) sheets. According to experimental and numerical results, it is shown that the resistance and stiffness of iron columns can be significantly increased with the use of longitudinal FRP sheets because of the reduction of the column slenderness, but also that transverse FRP sheets should be used to prevent any local buckling of the longitudinal FRP sheetsProhitec

Material characterization of timber

Tests caractéristiques du matériau bois dans le cadre de la recherche "Kser" avec la collaboration de CTIB (centre technique industriel du bois

Application of the component method to joints between hollow and open sections

édition revue et corrigé