• Structural Engineering and Mechanics
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• 제70권5호
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• pp.639-647
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• 2019

The performance of precast concrete structures is greatly influenced by the behaviour of beam-to-column connections. A single connection may be required to transfer several loads simultaneously so each one of those loads must be considered in the design. A good connection combines practicality and economy, which requires an understanding of several factors; including strength, serviceability, erection and economics. This research work focuses on the performance aspect of a specific type of beam-to-column connection using partly hidden corbel in precast concrete structures. In this study, the results of experimental assessment of the proposed beam-to-column connection in precast concrete frames was used. The purpose of this research is to develop and apply the Extreme Learning Machine (ELM) for moment-rotation prediction of precast beam-to-column connections. The ELM results are compared with genetic programming (GP) and artificial neural network (ANN). The reliability of the computational models was accessed based on simulation results and using several statistical indicators.

• Steel and Composite Structures
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• 제16권2호
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• pp.187-201
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• 2014

A new through-beam connection system for a concrete filled steel tube column to RC beam is proposed. In this connection, there are openings on the steel tube while the reinforced concrete beams are continuous in the joint zone. The moment and shear force at the beam ends can be transferred to column by continuous rebar and concrete. The weakening of the axial load and shear bearing capacity due to the opening of the steel tube can be compensated by strengthening steel tube at joint zone. Using this connection, construction of the joint can be made more convenient since welding and hole drilling in situ can be avoided. Axial compression and reversed cyclic loading tests on specimens were carried out to evaluate performance of the new beam-column connection. Load-deflection performance, typical failure modes, stress and strain distributions, and the energy dissipation capacity were obtained. The experimental results showed that the new connection have good bearing capacity, superior ductility and energy dissipation capacity by effectively strengthen the steel tube at joint zone. According to the test and analysis results, some suggestions were proposed to design method of this new connection.

• 대한조선학회지
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• 제14권4호
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• pp.3-14
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• 1977

There are many Beam-Column connections in general structures and ship structures. For simplicity and convenience of analysis, the connections are mostly considered hinged when not reinforced or rigidly fixed when reinforced. This paper has intended to analyze the Beam-Column connection which is assumed two dimensional flat plate. The analysis has been preformed by Finite Element Method following the change of moment of inertia at connection. The conclusion of this investigation is as follows: By reinforcing or increasing the moment of inertia at connection part, the stress distribution of whole structure and the stress concentration at that part are relieved. Displacements of beam(when column is fixed) are almost linearly decreasing by the change of moment of inertia at connection.

• Steel and Composite Structures
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• 제11권4호
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• pp.291-305
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• 2011

The new structure consisting of continuous compound spiral hoop reinforced concrete (CCSHRC)column and steel concrete composite (SCC) beam has both the advantages of steel structures and concrete structures. Two types of beam-to-column connections applied in this structural system are presented in this paper. The connection details are as follows: the main bars in beam concrete pass through the core zone for both types of connections. For connecting bar connection, the steel I-beam webs are connected by bolts to a steel plate passing through the joint while the top and bottom flanges of the beams are connected by four straight and two X-shaped bars. For bolted end-plate connection, the steel I-beam webs are connected by stiffened extended end-plates and eight long shank bolts passing through the core zone. In order to study the seismic behaviour and failure mechanisms of the connections, quasi-static tests were conducted on both types of full-scale connection subassemblies and core zone specimens. The load-drift hysteresis loops show a plateau for the connecting bar connection while they are excellent plump for bolted end-plate connection. The shear capacity formulas of both types of connections are presented and the values calculated by the formula agree well with the test results.

• Steel and Composite Structures
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• 제39권2호
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• pp.201-213
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• 2021

Currently, there is a lack of research in the design approach to avoid column wall failure in the concrete filled double skin steel tubular (CFDST) column-beam connections. In this paper, a finite element model has been developed and verified by available experimental data to analyze the failure mechanism of CFDST column-beam connections. Various finite element models with different column hollow ratios (χ) were established. The simulation result revealed that with increasing χ the failure mode gradually changed from yielding of end plate, to local failure of the column wall. Detailed parametric analyses were performed to study the failure mechanism of column wall for the CFDST column-beam connection, in which the strength of sandwiched concrete and steel tube and thickness of steel tube were incorporated. An analytical model was proposed to predict the moment resistance of the assembled connection considering the failure of column wall. The simulation results indicate that the proposed analytical model can provided a conservative prediction of the moment resistance. Finally, an upper bound value of χ was recommend to avoid column wall failure for CFDST column-beam connections.

• Coupled systems mechanics
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• 제3권2호
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• pp.195-211
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• 2014

When strong seismic forces act on reinforced concrete structures, their beam-column connections are very susceptible to damage during the earthquake event. The aim of this numerical work is to evaluate the influence of the internal steel reinforcement array on the nonlinear response of a RC beam-column connection when it is subjected to strong cyclic loading -as a seismic load. For this, two specimens (extracted from an experimental test of 12 RC beam-column connections reported in literature) were modeled in the Finite Element code FEAP considering different stirrup's arrays. In order to evaluate the nonlinear response of the RC beam-column connection, the 2D model takes into account the nonlinear thermodynamic behavior of each component: for concrete, a damage model is used; for steel reinforcement, it is adopted a classical plasticity model; in the case of the steel-concrete bonding, this one is considered perfect without degradation. At the end, we show a comparison between the experimental test's responses and the numerical results, which includes the distribution of shear stresses and damage inside the concrete core of the beam-column connection; in the other hand, the effects on the connection of a low and high state of confinement are analyzed for all cases.

• 국제초고층학회논문집
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• 제7권4호
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• pp.343-362
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• 2018

A simplified spring connection modelling approach for steel flush endplate beam-to-column connections in fire has been developed to enable realistic behaviour of connections to be incorporated into full-scale frame analyses at elevated temperature. Due to its simplicity and reliability, the proposed approach permits full-scale high-temperature frame analysis to be conducted without high computational cost. The proposed simplified spring connection modelling approach has been used to investigate the influence of connection ductility (both axial and rotational) on frame behaviour in fire. 2D steel and 3D composite frames with a range of beam spans were modelled to aid the understanding of the differences in frame response in fire where the beam-to-column connections have different axial and rotational ductility assumptions. The modelling results highlight that adopting the conventional rigid or pinned connection assumptions does not permit the axial forces acting on the connections to be accurately predicted, since the axial ductility of the connection is completely neglected when the rotational ductility is either fully restrained or free. By accounting for realistic axial and rotational ductilities of beam-to-column connections, the frame response in fire can be predicted more accurately, which is advantageous in performance-based structural fire engineering design.

• Steel and Composite Structures
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• 제31권3호
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• pp.319-327
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• 2019

This paper describes an experimental study of steel beam-column connections with or without expanded beam flanges with different geometries. The objectives of this study are to elucidate the cyclic behavior of these connections, identify the location of the plastic hinge zone, and provide useful test data for future numerical simulations. Five connection specimens are designed and tested under cyclic load. The test setup consists of a beam and a column connected together by a connection with or without expanded beam flanges. A constant axial force is applied to the column and a time varying point load is applied to the free end of the beam, inducing shear and moment in the connection. Because the only effect to be studied in the present work is the expanded beam flange, the sizes of the beam and column as well as the magnitude of the axial force in the column are kept constant. However, the length, width and shape of the expanded beam flanges are varied. The responses of these connections in terms of their hysteretic behavior, failure modes, stiffness degradation and strain variations are experimentally obtained and discussed. The test results show that while the influence of the expanded beam flanges on hysteretic behavior, stiffness degradation and energy dissipation capacity of the connection is relatively minor, the size of the expanded beam flanges does affect the location of the plastic hinge zone and strain variations in these beam-column joints. Furthermore, in terms of ductility, moment and rotational capacities, all five connections behave well. No weld fracture or premature failure occurs before the formation of a plastic hinge in the beam.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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• pp.85-88
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• 2004

In this study, a simple moment-resisting precast concrete beam-column connection is proposed for highly seismic zone using dywidag ductile rod [DDC]. DDC is superior system for ductility, energy dissipation capacity, connection strength, and drift capacity. A study was carried out to investigate the connection behavior subjected to cyclic inelastic loading. Four Precast beam-column interior connections and one monolithic connection will be tested. The variables will be examined were the strength relationship between joint's ductile rod and beam reinforcement for gain energy dissipation capacity. The specimens will be tested only reverse cyclic loading in accordance with a prescribed displacement history. Connection performance is evaluated on the basis of ductility, energy dissipation capacity, connection strength, and drift capacity. the precast connection using DDC is capable of matching of exceeding the performance of the monolithic connection and thereby provides moment-resisting behavior.

• Structural Engineering and Mechanics
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• 제24권3호
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• pp.291-306
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• 2006

In order to improve the constructability and meanwhile ensure excellent seismic behavior, several innovative composite connection details were conceived and studied by the authors. This paper reports experimental results and observations on seismic behavior of steel beam bolted to reinforced concrete column connections (bolted RCS or BRCS). The proposed composite connection details involve post tensioning the end plates of the steel beams to the reinforced concrete or precast concrete columns using high-strength steel rods. A rational design procedure was proposed to assure a ductile behavior of the composite structure. Strut-and-tie model analysis indicates that a bolted composite connection has a favorable stress transfer mechanism. The excellent capacity and behavior were then validated through five full-scale beam to column connection model tests.