Experimental and analytical investigations on the behaviour of building frames further to a column loss

peer reviewe

Non-dissipative joints in seismic resistant building frames - Bolted beam-to-column joints

peer reviewedAccording to Eurocode 8, earthquake resistant steel building frames shall be designed following either the “low dissipative structural behaviour concept” or the “dissipative structural behaviour concept”. In the second concept, the capability of parts of the structure to resist earthquake actions through inelastic behaviour is taken into account: energy is dissipated in plastic mechanisms. In such a design, it has to be ensured that the dissipative zones form where they are intended to and that they yield before other zones leave the elastic range. In particular, moment resisting frames are designed in such a way that plastic hinges develop at the extremities of the beams. These dissipative zones can be located either in the beams or in the beam-to-column joints. In this paper, non-dissipative bolted beam-to-column connections are considered. They must be sufficiently resistant to remain in elastic range while cyclic yielding develops in the dissipative zones located in the beams. Besides, the possibility that the actual yield strength of the beam is higher than the nominal value has to be taken into account by a material overstrength factor. Such an approach generally leads to very strong and thus expensive joints. In the present paper, a design strategy leading to more economical solutions for full-strength beam-to-column joints is detailed. This study was conducted within the framework of an RFCS project called HSS-SERF (High Strength Steel in Seismic Resistant Building Frames). The considered moment-resisting joints are part of seismic resistant building frames made of high strength steel composite columns and mild carbon steel beams. The columns are either partially-encased wide-flange columns (H columns) or concrete-filled rectangular hollow-section columns (RHS columns). The proposed joint configuration uses hammer-heads extracted from the beam profile. To fulfil the resistance requirement taking account of the possible overstrength of the beam, the resistant moment of the joint is decomposed in the contributions of the different components involved. Then, no overstrength factor needs to be considered for the components related to the beam itself and to the hammer-heads. This approach is in full accordance with the basic principles of Eurocode 8 and can decrease much the required resistance of the joints provided some conditions are fulfilled, meaning lower costs

Robustness of steel building structures following a column loss

peer reviewe

Beam to concrete-filled rectangular hollow section column joints using long bolts

peer reviewedThis paper presents a research on a specific type of unstiffened extended end-plate joint used to connect I-shaped beams to concrete-filled rectangular hollow section columns. The main idea is to use long bolts throughout the column to connect the beam end-plates, so avoiding intermediate connecting elements (e.g. a reverse U channel) or special bolts (e.g. blind bolts). However, the use of long bolts for beam-to-column connections is still rare in the construction and no design procedure exists in the Eurocodes; this justifies the pre-sent research. Firstly, a test program within a RFCS European project titled HSS-SERF “High Strength Steel in Seismic Resistant Building Frames”, 2009-2013 was performed. In this project, specimens subjected to sig-nificant bending moments (and shear) or to shear only was defined. Then, analytical developments based on the component approach and aimed at predicting the joint response have been carried out; their validity is demonstrated through comparisons with the tests. Finally, design guidelines have been provided

Analysis of temporal gait features extracted from accelerometer-based signals during ambulatory walking in Parkinson’s disease

Objective: To perform a proof-of-concept study showing the utility of versatile algorithms aimed at objectively quantifying the duration of refined gait features during ambulatory walking in a patient with Parkinson’s disease (PD) in ON and OFF medication states as compared with an age-matched control subject

Behaviour of single sided composite joints at room temperature and in case of fire after an earthquake

peer reviewedIn 2003, a European research program entitled “PRECIOUS - Prefabricated composite beam-to-concrete filled tube or partially reinforced-concrete-encased column connections for severe seismic and fire loadings” and funded by the Research Fund for Coal and Steel (RFCS) was initiated for three years (Bursi et al, 2008). The objective of this project was to develop fundamental data, design guidelines and prequalification tools for two types of composite beam-to-column joints able to ensure a suitable behaviour during an earthquake and its eventual subsequent fire. At the University of Liege, as part of this project, analytical and numerical investigations were conducted mainly on single-sided beam-to-column composite joints at room and at elevated temperatures. The present paper summarizes the activities developed within this project and presents the main achievements

A Code Tagging Approach to Software Product Line Development:An Application to Satellite Communication Libraries

International audienceSoftware product line engineering seeks to systematise reuse when developing families of similar software systems so as to minimise development time, cost and defects. To realise variability at the code level, product line methods classically advocate usage of inheritance, components, frameworks, aspects or generative techniques. However, these might require unaffordable paradigm shifts for developers if the software was not thought at the outset as a product line. Furthermore, these techniques can be conflicting with a company's coding practices or external regulations. These concerns were the motivation for the industry- university collaboration described in this paper in which we developed a minimally intrusive coding technique based on tags. The approach was complemented with traceability from code to feature diagrams which were exploited for automated configuration. It is supported by a toolchain and is now in use in the partner company for the development of flight grade satellite communica- tion software libraries

Complete analytical procedure to assess the response of a frame submitted to a column loss

The present paper gives a global overview on recent developments performed at the University of Liege on structural robustness of buildings for the specific scenario ‘‘loss of a column’’. In particular, a complete analytical method to assess the response of a 2D frame losing statically one of its columns is presented in details. This method is based on the development of alternative load paths in the damaged structure and takes into account the couplings between the different parts of the structure which are differently affected by the column loss. Also, the validation of the developed method through comparison to experimental and numerical evidences is presented