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Lightweight steel framed systems (LWS) are innovative construction systems whose application has been steadily increasing over the years thanks to the huge benefits in terms of structural and environmental efficiency. Typical LWS products are usually combined with gypsum, wood and cement-based panels and can be used to build both structural and non-structural systems. After a brief description of the most common LWS constructional systems, this paper provides a state-of-the-art review of their behaviour under seismic actions. In particular, the main past and ongoing research works on lightweight steel framed structural and non-structural systems are briefly summarized and a critical comparison among seismic codes available in North America, Europe and Oceania is presented. Finally, an overview of studies carried out at the University of Naples "Federico II", Italy, on this topic is presented together with the shaking table tests carried out recently on both LWS structural and non-structural architectural systems. • Description of the most common LWS structural and non-structural constructional systems is given. • Key issues concerning the seismic behaviour of both LWS seismic resistant and non-structural systems are briefly stated. • Main past and ongoing researches on LWS framed systems are briefly summarized. • A critical comparison among seismic codes available in North America, Europe and Oceania is presented. • An overview of recent studies on LWS framed systems carried out at the University of Naples Federico II is provided. [ABSTRACT FROM AUTHOR]

An extensive set of experimental programme on the behaviour of innovative ring-bar reinforced connections composed of T-shaped concrete-filled steel tubular (CFST) columns and reinforced concrete (RC) beams with slabs are reported in this study. Specifically, for the proposed connection, the T-shaped CFST column is welded with an H-shaped steel corbel, which is embedded into the reinforced concrete beam and slab. Moreover, a few ring-bars are fabricated to improve the seismic resistance capacity of this connection. A total of six specimens are tested: one specimen is tested under monotonic loading to investigate the load-displacement relationship and the development of strains; and the other five specimens are tested under cyclic loading to obtain the seismic behaviour of these specimens. The test results demonstrate that the seismic behaviour of the proposed connections is prominent and that the diameter and number of ring-bar and length of steel corbel are found to be significant factors of the seismic behaviour of the connections. Complementary to the experiments, a finite element (FE) model is developed to further analyse the experimental results by illustrating the failure modes of the specimens and extending the parametric studies which are not studied through the limited experiments. The comparison between the FE analysis and the experimental results demonstrates the accuracy of the proposed model. Numerical results indicate that the ring-bar and slab are able to increase the stiffness and bearing capacity of the specimens; the reinforcement ratio of beam, the concrete strength of the beam and slab play important roles in improving the ultimate strength of the specimens. [ABSTRACT FROM AUTHOR]

The stainless-clad (SC) bimetallic steel is an advanced high-performance steel with high strength and outstanding corrosion-resistant performance. It is especially competitive in the application of structures with demands of high corrosion resistance. However, the current research on SC bimetallic steels mainly focuses on the material level rather than the structural level, and it is not clear whether the excellent performance of materials can be reflected in the seismic behaviours of members. Thus, cyclic behaviours of SC bimetallic steel members need to be thoroughly investigated to fill the research gap and expand the application fields of this steel in the seismic region. To this end, this paper aims to study the cyclic behaviour of SC bimetallic steel box-section beam-columns subjected to combined constant axial load and low-cycle reciprocating lateral load through full-scale tests and finite element (FE) models. Four specimens were tested, and the influence of the width-to-thickness ratio of component plates was clarified through comparative research on the test processes, buckling details, hysteresis curves, strain curves, energy dissipation and ductility performance. Moreover, a refined FE model adopted single-layered modelling or double-layered modelling was developed respectively; and then, the model validation, the shear stress distribution at the bonding interface and parametric analyses were carried out. Research showed that the SC bimetallic steel beam-columns exhibit good energy dissipation and seismic behaviour under cyclic loadings; the smaller width-to-thickness ratio or axial load ratio could result in the plumper hysteresis curves, more sufficient energy dissipation and superior ductility performance; the ductility performance of SC bimetallic steel column was significantly improved; the ductility-based design approach proposed herein could approximately quantify the ductility performance of SC bimetallic steel box-section column, which could provide a reference for the seismic design. • The first application of stainless-clad (SC) bimetallic steel in seismic steel frames. • Four full-scale box-section SC bimetallic steel beam-columns are tested. • Two finite element (FE) modelling approaches are developed. • Influence of critical parameters is clarified in depth by 160 FE models. • A ductility-based design approach of the SC bimetallic steel members is proposed. [ABSTRACT FROM AUTHOR]

The existing wall–beam joints of bundled lipped channel-concrete composite wall structures (BLC–CCWSs) are mainly fabricated by welding thin-walled steel tubes and hot-rolled steel plates; however, the application of this technology requires further improvement. In this paper, an innovative anchored prefabricated wall–beam joint was presented. The seismic behaviour of joints was studied by cyclic loading tests of four groups of full-scale specimens, and a hysteretic model of joints was established. The main conclusions are as follows: (1) standard joints fail in the ideal beam plastic hinge damage mode, resulting in a good hysteretic characteristics, energy dissipation capacity, stable bearing capacity and stiffness degradation performance. (2) The anchorage length of the embedment, circumferential weld around end plate and the anchor plate have significant influences on the seismic behaviour of the joints. Sufficient anchorage length and the inclusion of the anchor plate and circumferential weld around end plate can delay the pulling out of the embedment and improve the bearing capacity and the hysteretic performance of a joint before failure. (3) The main contributor to the nonlinear deformation of the joints is the plastic hinge rotation or the rotation caused by sliding of the embedment. (4) The beam end strain can be reduced when the flange is widened. The strain distribution of the embedments is not uniform, and the shear strain in the panel zone is small. (5) The established hysteretic model can take the degradation of stiffness and strength into consideration, and thus produces accurate results that are still conservative and that can be applied in engineering practice. • An innovative anchored prefabricated wall–beam joint was proposed for BLC–CCWS. • The seismic behaviour of joints was studied by full-scale cyclic loading tests. • The influence mechanism of the joint structure on the seismic behaviour of the joint was clarified. • A hysteretic model of the joints was established. [ABSTRACT FROM AUTHOR]

Abstract: In the current Japanese bridge design code, the seismic load of only one direction (1-dimension, 1-d) is considered. However, in fact, an actual seismic load has three components for N–S (north–south), E–W (east–west) and U–D (up–down) directions. The current paper presents a series of numerical results of steel box columns, which are used as piers of viaduct, under 3-d seismic load with 3 components. Two types of ground motion patterns of the main shock and the maximum aftershock measured in the Chuetsu Earthquake in 2004 are used as the seismic load. The results indicate that the severer deformation arises in the columns under 2-d (N–S and E–W components) or 3-d seismic load than the 1-d load by the main shock. However, under the aftershock, which contains ground motion of higher frequency, 1-d load gives larger displacement. [Copyright &y& Elsevier]

Abstract: This paper describes eight tests carried out on thin-walled steel tube confined concrete (TWSTCC) column to reinforced concrete (RC) beam joints subjected to cyclic loading, where the column cross-sectional type and the level of axial load in the column were selected as test parameters. In addition, two concrete filled thin-walled steel tubular column to RC beam joints were also tested for comparison. Each TWSTCC joint specimen consisted of a TWSTCC column and a RC beam pass through the column to represent an interior joint in a building. The experimental results are analysed to evaluate the influences of different testing parameters on the performance of the beam-column joints. It was found that the TWSTCC joints show generally excellent seismic performance and is adoptable in practical engineering, particularly in earthquake zone. [Copyright &y& Elsevier]

This paper firstly proposed steel-concretes-steel sandwich walls with J-hook connectors (SCSWJs) as protective structures in the Arctic offshore platforms. Followed, six large scale SCSWJs were tested under lateral cyclic loading to investigate their lateral seismic behaviours. The investigated parameters in the testing program included spacing of J-hook, concrete core strength, thickness of steel faceplate, and aspect ratio. Seismic behaviours of SCSWJs were reported in details, and the effects of these parameters on their seismic behaviours were reported and discussed. The test results showed that the SCSWJ failed in flexure mode with characteristics of tensile yielding of side plate and steel faceplate, concrete crushing at the bottom toe, and outward local buckling of steel faceplates. Pinching effect was observed in the load versus lateral drift curves after the peak load due to premature local buckling of side plates and faceplates locating between the first and second row of J-hook from the bottom. This paper developed analytical models to predict the peak lateral resistance of SCSWJ. The validations against 12 results from six cyclic tests confirmed that the developed models offered reasonable but conservative predictions on the peak lateral resistance of SCSWJ. This study promotes the applications of the SCSWJ in the earthquake-prone Arctic regions. • Novel SCS sandwich walls with J-hook have been proposed for civil and offshore structures. • Seismic behaviors of novel SCSWJ shear walls are evaluated by large-scale tests. • Key parameters influencing seismic performances of SCSWJ are studied and reported. • Analytical models are developed for ultimate lateral shear resistance of SCSWJ. [ABSTRACT FROM AUTHOR]

A new type of composite shear wall, composed of dual steel plates, vertical stiffening steel plates to connect the dual plates and concrete infilled in the vertical channels formed by these steel plates, is proposed. Fifteen specimens were tested under horizontal cyclic loads, along with a constant vertical axial force, to investigate their seismic behaviour. Specimen failure mainly included three modes: severe local buckling at the corners of the flange plates and boundary channels, damage of the concrete occurring in the middle and bottom of the shear wall and local buckling waves originating at the middle of the specimen. All the specimens exhibited a good deformation capacity: the ultimate drift ratios of the specimens reached an average value of 4.55%, and the ductility has an average value of 4.0. The test results indicated that the thickness of the shear wall and the number of channels in the shear wall have a significant effect on the ductility of the specimens. However, changing the number of channels in the walls has a negligible effect on the shear strength of the wall. Formulas to predict the maximum shear strength and initial stiffness of the shear wall are proposed, and it is verified that they can provide a satisfactory prediction for most specimens, with an error within 10%. • Fifteen steel concrete composite shear walls subjected to cyclic load under high axial load ratio were tested. • The composite shear walls exhibited high load-carrying capacities, good ductility and excellent energy dissipation ability. • Increasing the thickness of wall can enhance the maximum strength and ductility but decrease stiffness degradation ratio. • Increasing the number of channels in the wall can increase the ductility but does not obviously affect the maximum strength. • The simplified formulas were proposed to evaluate the maximum shear strength and initial stiffness of the specimens. [ABSTRACT FROM AUTHOR]