A NEW SIMPLIFIED ANALYTICAL DESIGN METHOD FOR STEEL AND COMPOSITE SWAY FRAMES

in Journal of Constructional Steel Research (2013)

Eurocode 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 ... [more ▼]

Eurocode 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 Liège 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. [less ▲]

Strength enhancements in cold-formed structural sections — Part I: 2 Material testing

in Journal of Constructional Steel Research (2013), 83

This paper describes a material test programme carried out as part of an extensive study into the prediction of strength enhancements in cold-formed structural sections. The experiments cover a wide range ... [more ▼]

This paper describes a material test programme carried out as part of an extensive study into the prediction of strength enhancements in cold-formed structural sections. The experiments cover a wide range of cross-section geometries – twelve Square Hollow Sections (SHS), five Rectangular Hollow Sections (RHS) and one Circular Hollow Section (CHS), and materials – austenitic (EN 1.4301, 1.4571 and 1.4404), ferritic (EN 1.4509 and 1.4003), duplex (EN 1.4462) and lean duplex (EN 1.4162) stainless steel and grade S355J2H carbon steel. The experimental techniques implemented, the generated data and the analysis methods employed are fully described. The results from the current test programme were combined with existing measured stress-strain data on cold-formed sections from the literature and following a consistent analysis of the combined data set, revised values for Young’s modulus E and the Ramberg-Osgood material model parameters n, n' 0.2,u and n'0.2,1.0 are recommended. A comparison between the recommended values and the codified values provided in AS/NZS 4673, SEI/ASCE-8 and EN 1993-1-4 is also presented. The test results are also used in a companion paper for developing suitable predictive models to determine the strength enhancements in cold-formed structural sections that arise during the manufacturing processes. [less ▲]

Experimental and numerical investigation of high-strength steel circular columns subjected to fire

in Journal of Constructional Steel Research (2013), 80

This paper presents an experimental–numerical study on the behaviour of High Strength Steel (HSS) columns at elevated temperature, both on Circular Hollow Sections (CHS) and on a Concrete Filled Tube (CFT ... [more ▼]

This paper presents an experimental–numerical study on the behaviour of High Strength Steel (HSS) columns at elevated temperature, both on Circular Hollow Sections (CHS) and on a Concrete Filled Tube (CFT). The measured yield strength of the circular sections was in the order of 820 MPa. In detail, three HSS CHS and a HSS CFT were tested under the standard ISO fire with constant eccentric compression applied load. The evolution of temperature and deformation patterns were measured by means of a comprehensive instrumentation made of thermocouples and displacement transducers. Numerical analyses were performed and compared with experimental data by employing stress–strain relationships of carbon steel at elevated temperatures provided by the Eurocodes associated to two different sets of reduction factors: i) those provided by the Eurocodes valid up to S460 steel grades; and ii) those proposed in the literature and based on tests on HSS. [less ▲]

Post earthquake fire and seismic performance of welded steel-concrete composite beam-to-column joints

in Journal of Constructional Steel Research (2011), 67

The performance of steel-concrete composite full strength joints endowed with concrete filled tubes, designed with a multi-objective methodology dealing with seismic actions followed by fire is presented ... [more ▼]

The performance of steel-concrete composite full strength joints endowed with concrete filled tubes, designed with a multi-objective methodology dealing with seismic actions followed by fire is presented in this paper. In detail, instead of a traditional single-objective design where fire safety and seismic safety are independently achieved and the sequence of seismic and fire loading are not taken into account, the proposed design approach guarantees: i) both seismic safety and fire safety with regard to accidental actions; ii) fire safety for at least 15 min fire exposure on a joint characterised by stiffness deterioration and strength degradation due to seismic loading. In order to achieve the multi-objective design, full strength beam-to-composite tubular column joints were designed by means of the component method of Eurocode 4 Part 1-1 and Eurocode 3 Part 1-8, while Eurocode 4 Part 1-2 was considered for fire design. Moreover, to face seismic-induced fire, they were enhanced with specific joint components which will be detailed. Both the experimental program and the results provided by seismic tests, pre-damaged tests and fire tests carried out on beam-to-column joints are presented and discussed. The results emonstrate their adequacy in terms of design and performance. Moreover, non-linear numerical simulations clearly show that these joints can be deemed adequate for moment resisting frames of medium ductility class characterized by a behaviour factor of about 4. [less ▲]

Lateral-torsional buckling of stainless steel I-beam in case of fire

in Journal of Constructional Steel Research (2008), 64

This work presents a numerical study of the behaviour of stainless steel I-beams subjected to lateral–torsional buckling in case of fire and compares the obtained results with the beam design curves of ... [more ▼]

This work presents a numerical study of the behaviour of stainless steel I-beams subjected to lateral–torsional buckling in case of fire and compares the obtained results with the beam design curves of Eurocode 3. New formulae for lateral–torsional buckling, that approximate better the real behaviour of stainless steel structural elements in case of fire are proposed. These new formulae were based on numerical simulations using the program SAFIR, which was modified to take into account the material properties of the stainless steel. [less ▲]

Interaction of global and local buckling in welded RHS compression members

in Journal Of Constructional Steel Research (2008), 64(7-8), 755-765

This paper presents the results of a research project analysing some aspects of the stability failure of thin-walled compression members that are likely to exhibit combined global and local buckling. In ... [more ▼]

This paper presents the results of a research project analysing some aspects of the stability failure of thin-walled compression members that are likely to exhibit combined global and local buckling. In particular, the influence of various imperfections, namely residual stresses due to welding and local as well as global geometrical defects, on the load-carrying capacity was Subjected to detailed experimental and numerical investigations. The insights obtained into the structural behaviour led to a proposal for modification of the non-dimensional slenderness used in the global buckling verification, and to the recommendation of a shift from the Currently applied European buckling curve to a more favourable one in the case of non-stiffened members with welded box sections subjected to pure compression. (C) 2008 Elsevier Ltd. All rights reserved. [less ▲]

Seismic Design and Performance of Composite Frames

in Journal of Constructional Steel Research (2004), (60),

In this study, the seismic design and performance of composite steel-concrete frames are studied. The new Eurocode 4 and Eurocode 8, which are in a preliminary stage at the moment, are employed for the ... [more ▼]

In this study, the seismic design and performance of composite steel-concrete frames are studied. The new Eurocode 4 and Eurocode 8, which are in a preliminary stage at the moment, are employed for the design of six composite steel-concrete frames. The deficiencies of the codes and the clauses that cause difficulties to the designer are discussed. The inelastic static pushover analysis is employed for obtaining the response of the frames and the overstrength factors. The evaluation of the response modification factor takes place by performing incremental time-history analysis up to the satisfaction of the yield and collapse limit states in order to investigate the conservatism of the code. The last purpose of this study is to investigate if elastically designed structures can behave in a dissipative mode. [less ▲]

General report - Session on connections

in Journal of Constructional Steel Research (2000), 55

As a result of a world-wide intensive research activity, a new design concept for structural moment resistant joints has been suggested and implemented in design codes. In the present paper, its ... [more ▼]

As a result of a world-wide intensive research activity, a new design concept for structural moment resistant joints has been suggested and implemented in design codes. In the present paper, its background is first briefly described and the main contributions to its development are presented. As a matter of fact, because of the high number of past and ongoing researches, reports and papers devoted to this topic, an exhaustive list of all these works could not be established in a limited number of pages. The possibilities of extension of the new design concepts, which have been first developed for steel beam-to-column joints under static loading, are particularly pointed out. This aspect appears quite important as in the near future it should provide designers with a unified design approach for structural joints whatever their loading, their configurations and the nature of their constitutive material(s). [less ▲]

Benchmarks for finite element modelling of bolted steel connections

in Journal of Constructional Steel Research (1997), 43(Nos 1-3),

A Simple Model for the Fire Resistance of Axially Loaded Members - Comparison with experimental results

in Journal of Constructional Steel Research (1996), 37