• Steel and Composite Structures
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• 제46권2호
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• pp.237-252
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• 2023

The article describes the development of a novel dissipative bracing connection device (identified by the acronym DRBrC) for concentrically braced frames in steel and composite structures. The origins of the device trace back to the seminal work of Kelly, Skinner and Heine (1972), and, more directly related, to the PIN-INERD device, overcoming some of its limitations and greatly improving the replaceability characteristics. The connection device is composed of a rigid housing, connected to both the brace and the beam-column connection (or just the column), in which the axial force transfer is achieved by four-point bending of a dissipative pin. The experimental validation stages, presented in detail, consisted of a preliminary testing campaign, resulting in successive improvements of the original device design, followed by a systematic parametric testing campaign. That final campaign was devised to study the influence of the constituent materials (S235 and Stainless Steel, for the pin, and S355 and High Strength Steel, for the housing), of the geometry (four-point bending intermediate spans) and of the loading history (constant amplitude or increasing cyclic alternate). The main conclusions point to the most promising DRBrC device configurations, also presenting some suggestions in terms of the replaceability requirements.

• Steel and Composite Structures
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• 제14권6호
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• pp.547-569
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• 2013

In recent years there has been increasing international interest about designing structures that cost less to repair after they have been subjected to strong earthquakes. Considering this interest, an innovative repairable fuse device has been developed for dissipative beam-to-column connections in moment-resisting composite steel and concrete frames. The seismic performance of the device was assessed through an extensive experimental program comprising ten cyclic and two monotonic tests. These tests were conducted on a single beam-to-column specimen with different fuse devices for each test. The devices varied in terms of the chosen geometric and mechanical parameters. The tests showed that the devices were able to concentrate plasticity and to dissipate large amounts of energy through non-linear behavior. Numerical models were developed with Abaqus and simplified design models are also proposed.

• Steel and Composite Structures
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• 제15권4호
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• pp.357-377
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• 2013

In order to study the degradation and damage behaviors of steel frame welded connections, two series of tests in references with different connection constructions were carried out subjected to various cyclic loading patterns. Hysteretic curves, degradation and damage behaviours and fatigue properties of specimens were firstly studied. Typical failure modes and probable damage reasons were discussed. Then, various damage index models with variables of dissipative energy, cumulative displacement and combined energy and displacement were summarized and applied for all experimental specimens. The damage developing curves of ten damage index models for each connection were obtained. Finally, the predicted and evaluated capacities of damage index models were compared in order to describe the degraded performance and failure modes. The characteristics of each damage index model were discussed in depth, and then their distributive laws were summarized. The tests and analysis results showed that the loading histories significantly affected the distributive shapes of damage index models. Different models had their own ranges of application. The selected parameters of damage index models had great effect on the developing trends of damage curves. The model with only displacement variable was recommended because of a more simple form and no integral calculation, which was easier to be formulated and embedded in application programs.

• Steel and Composite Structures
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• 제45권2호
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• pp.231-248
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• 2022

Hybrid Steel-Trussed Concrete Beam (HSTCB) is structural typology suitable for light industrialization. HSTCBs usually cover long span with small depths, which lead to significant amount of longitudinal rebars. The latter make beam-column joints more prone to damage due to earthquake-induced cyclic actions. This phenomenon can be avoided using friction-based BCCs. Friction devices at Beam-to-Column Connections (BCCs) have become promising solutions to reduce the damage experienced by structural members during severe earthquakes. Few solutions have been developed for cast-in-place Reinforced Concrete (RC) and steel-concrete composite Moment Resisting Frames (MRFs), because of the difficulty of designing cost-effective damage-proof connections. This paper proposes a friction-based BCC for RC MRFs made with HSTCBs. Firstly, the proposed connection is described, and its innovative characteristics are emphasized. Secondly, the design method of the connection is outlined. A detailed 3D FE model representative of a beam-column joint fitted with the proposed connection is developed. Several monotonic and cyclic analyses are performed, investigating different design moment values. Lastly, the numerical results are discussed, which demonstrate the efficiency of the proposed solution in preventing damage to RC members, and in ensuring satisfactory dissipative capacity.

• Computers and Concrete
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• 제23권2호
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• pp.81-95
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• 2019

The unexpected seismic interaction of dry-assembled precast concrete frame structures typical of the European heritage with their precast cladding panels brought to extensive failures of the panels during recent earthquakes due to the inadequateness of their connection systems. Following this recognition, an experimental campaign of cyclic and pseudo-dynamic tests has been performed at ELSA laboratory of the Joint Research Centre of the European Commission on a full-scale prototype of precast structure with vertical and horizontal cladding panels within the framework of the Safecladding project. The panels were connected to the frame structure by means of innovative arrangements of fastening systems including isostatic, integrated and dissipative. Many of the investigated configurations involved a strong frame-cladding interaction, modifying the structural behaviour of the frame turning it into highly non-linear since small deformation. In such cases, properly modelling the connections becomes fundamental in the framework of a design by non-linear dynamic analysis. This paper presents the peculiarities of the numerical models of precast frame structures equipped with the various cladding connection systems which have been set to predict and simulate the experimental results from pseudo-dynamic tests. The comparison allows to validate the structural models and to derive recommendations for a proper modelling of the different types of existing and innovative cladding connection systems.