Behaviour of steel joints under fire loading

Luís Simões da Silva,Aldina Santiago,Paulo Vila Real,David Moore 국제구조공학회 2005 Steel and Composite Structures, An International J Vol.5 No.6

This paper presents a state-of-the-art on the behaviour of steel joints under fire loading and some recent developments in this field, currently being carried out by the authors. Firstly, a review of the experimental research work on steel joints is presented, subdivided into isolated member tests, sub-structure tests and tests on complete building structures. Special emphasis is placed on the seventh Cardington test, carried out by the authors within a collaborative research project led by the Czech Technical University in Prague. Secondly, a brief review of various temperature distributions within a joint is presented, followed by a discussion of the behaviour of isolated joints at elevated temperature, focussing on failure modes and analytical procedures for predicting the moment-rotation behaviour of joints at elevated temperature. Finally, a description of the coupled behaviour of joints as part of complete structures is presented, describing previous work and investigations on real fire (including heating and cooling phases) currently being carried out by the authors.

Safety Assessment of Eurocode 3 Stability Design Rules for Prismatic Members in Bending and Compression

Luís Simões da Silva,Trayana Tankova,Carlos Rebelo 한국강구조학회 2020 International Journal of Steel Structures Vol.20 No.1

This paper presents the safety assessment of Eurocode 3—part 1-1 (Eurocode in EN 1993-1-1, Eurocode 3: design of steel structures—part 1-1: general rules and rules for buildings, CEN, Brussels, 2005) rules for hot-rolled members with I and H cross-sections loaded in bending and compression. The safety assessment follows the recommendations of Annex D of EN 1990 (Eurocode in EN 1990, Eurocode—basis of structural design, CEN, Brussels, 2002). It is based on a large number (11,345) of numerical simulations (GMNIA) covering various relevant parameters. The assessment aimed at the justifi cation of the partial factors to be used in the design of members under bending and compression as part of the ongoing process of revision of Eurocode 3—part 1-1. For that, it covered the application of the interaction factors given in Annex B/Method 2 of the current version of Eurocode 3—part 1-1 which will be the only method in the future version of Eurocode 3. In addition, the interaction factors were applied with the new buckling curves for lateral-torsional buckling, as they will appear in the new version. The assessment showed consistent results across the subsets considered with low variability and partial factors generally lower than 1.0. Finally, the γ M * values are compared for fl exural buckling of columns, lateral-torsional buckling of beams with the results obtained for beam-columns considering f y , cross-section geometry and E as random variables, using the same statistical characterization of the random variables. It is observed that the partial factors obtained beam-columns are lower than those obtained for columns and beams. In conclusion, based on combination of the results obtained it was possible to recommend a global value of γ M1 = 1.0.

Behaviour of flush end-plate beam-to-column joints under bending and axial force

Luís Simões da Silva,Luciano R. O. de Lima,Pedro C. G. da S. Vellasco,Sebastião A. L. de Andrade 국제구조공학회 2004 Steel and Composite Structures, An International J Vol.4 No.2

Steel beam-to-column joints are often subjected to a combination of bending and axial forces. The level of axial forces in the joint may be significant, typical of pitched-roof portal frames, sway frames or frames with incomplete floors. Current specifications for steel joints do not take into account the presence of axial forces (tension and/or compression) in the joints. A single empirical limitation of 10% of the beam’s plastic axial capacity is the only enforced provision in Annex J of Eurocode 3. The objective of the present paper is to describe some experimental and numerical work carried out at the University of Coimbra to try to extend the philosophy of the component method to deal with the combined action bending moment and axial force.

Cyclic behaviour of end-plate beam-to-column composite joints

Rui Simões,Luís Simões da Silva,Paulo J.S. Cruz 국제구조공학회 2001 Steel and Composite Structures, An International J Vol.1 No.3

An experimental research program on end-plate beam-to-column composite joints under cyclic loading is presented. The major focus relates to the identification of the contribution of the concrete confinement in composite columns to the behaviour of the joint, on internal nodes and external nodes, together with an assessment of degradation of strength and stiffness in successive loading cycles. From the experimental results it was possible to identify the various failure modes and to fit the corresponding hysteretic curves to the Richard-Abbott and Mazzolani models. These curve-fitting exercises highlighted the need to adapt both models, either for improved ease of application, or to deal with some aspects previously not covered by those models.

Experimental investigation of the behaviour of a steel sub-frame under a natural fire

Aldina Santiago,Luís Simões da Silva,Gilberto Vaz,Paulo Vila Real,António Gameiro Lopes 국제구조공학회 2008 Steel and Composite Structures, An International J Vol.8 No.3

This paper details a testing facility (“NATURAL FIRE FACILITY”) that allows closelycontrolled experimental testing on full-scale sub-frames while reproducing the spatially transient temperature conditions measured in real fires. Using this test facility, an experimental investigation of six steel sub-frames under a natural fire was carried out at the Department of Civil Engineering of the University of Coimbra. The main objective of these tests was to provide insight into the influence of these connection types on the behaviour of steel sub-structures under fire. The experimental layout is defined by two thermally insulated HEA300 columns and an unprotected IPE300 beam with 5.7 m span, supporting a composite concrete slab. Beam-to-column connections are representative of the most common joint type used on buildings: welded joints and extended, flush and partial depth plate. Finally, the available results are presented and discussed: evolution of the steel temperature; development of displacements and local deformations and failure modes on the joints zone.

Rayleigh-Ritz procedure for determination of the critical load of tapered columns

Liliana Marques,Luís Simões da Silva,Carlos Rebelo 국제구조공학회 2014 Steel and Composite Structures, An International J Vol.16 No.1

EC3 provides several methodologies for the stability verification of members and frames. However, when dealing with the verification of non-uniform members in general, with tapered cross-section, irregular distribution of restraints, non-linear axis, castellated, etc., several difficulties are noted. Because there are yet no guidelines to overcome any of these issues, safety verification is conservative. In recent research from the authors of this paper, an Ayrton-Perry based procedure was proposed for the flexural buckling verification of web-tapered columns. However, in order to apply this procedure, Linear Buckling Analysis (LBA) of the tapered column must be performed for determination of the critical load. Because tapered members should lead to efficient structural solutions, it is therefore of major importance to provide simple and accurate formula for determination of the critical axial force of tapered columns. In this paper, firstly, the fourth order differential equation for non-uniform columns is derived. For the particular case of simply supported web-tapered columns subject to in-plane buckling, the Rayleigh-Ritz method is applied. Finally, and followed by a numerical parametric study, a formula for determination of the critical axial force of simply supported linearly web-tapered columns buckling in plane is proposed leading to differences up to 8% relatively to the LBA model.

Calibration of model parameters for the cyclic response of end-plate beam-to-column steel-concrete composite joints

Pedro Nogueiro,Luís Simões da Silva,Rita Bento,Rui Simões 국제구조공학회 2009 Steel and Composite Structures, An International J Vol.9 No.1

Composite joints, considering the composite action of steel and concrete, exhibit, in general, high strength and high ductility. As a consequence, the use of this type of joint has been increasing in many countries, especially in those that are located in earthquake-prone regions. In this paper, a hysteretic model with pinching is presented that is able to reproduce the cyclic response of steel and composite joints. Secondly, the computer implementation and adaptation of the model in a spring element within the computer code. Seismosoft is described. The model is subsequently calibrated using a series of experimental test results for composite joints subjected to cyclic loading. Finally, typical parameters for the various joint configurations are proposed.

Experimental Behaviour of the Reverse Channel Joint Component at Elevated and Ambient Temperatures

Fernanda Lopes,Aldina Santiago,Luís Simões da Silva,Tim Heistermann,Milan Veljkovic,José Guilherme da Silva 한국강구조학회 2013 International Journal of Steel Structures Vol.13 No.3

The reverse channel connection appears to have the best combination of desirable features under fire loading: moderate construction cost, ability to develop catenary action and extremely high ductility through deformation of the web channel (Ding and Wang, 2007). This paper presents the results of an experimental investigation of a reverse channel component conducted at the University of Coimbra as part of the European RFCS COMPFIRE Project, the main focus of which is to characterise the behaviour of steel joints that connect steel beams to concrete-filled tubular columns under natural fire loading. A series of tensile and compressive tests at ambient and elevated temperatures was conducted. The purposes of the experimental tests were to characterise the strength, stiffness and ductility of this joint component and to establish a relationship between force,displacement and temperature.