• Advances in concrete construction
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• v.3 no.3
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• pp.237-250
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• 2015

Beam-column joints are highly vulnerable locations which are to be designed for high ductility in order to take care of unexpected lateral forces such as wind and earthquake. Previous investigations reveal that the addition of steel fibres to concrete improves its ductility significantly. Also, due to presence of slab the strength and ductility of the beam increases considerably and ignoring the effect of slab can lead to underestimation of beam capacity and defiance of strong column weak beam concept. The influence of addition of steel fibres on the strength and behaviour of steel fibre reinforced high performance concrete (SFRHPC) interior beam-column-slab joints was investigated experimentally. The specimens were subjected to reverse cyclic loading. The variable considered was the volume fraction of crimped steel fibres i.e., 0%, 0.5% and 1.0%. The results show that the addition of steel fibres improves the first crack load, strength, ductility, energy absorption capacity and initial stiffness of the beam.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.419-422
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• 1999

This study was intended to investigate the cyclic behavior of high strength concrete beam-column connection. Four assemblies were designed 2/3 scale beam-column-slab joint and tested. The obtained results are follows. 1) The transverse beams increase the shear resistance and ductility of joint, 2) The slab was contributed to increase of the flexural capacity of the beam, but was not contributed to increase the joint ductility under lateral loads.

• Structural Engineering and Mechanics
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• v.5 no.5
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• pp.645-662
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• 1997

A nonlinear semi-three-dimensional layered finite element procedure is developed for cracking and failure analysis of reinforced concrete beams and the spandrel beam-column-slab connections of flat plates. The layered element approach takes the elasto-plastic failure behaviour and geometric nonlinearity into consideration. A strain-hardening plasticity concrete model and a smeared steel model are incorporated into the layered element formulation. Further, shear failure, transverse reinforcement, spandrel beams and columns are successfully modelled. The proposed method incorporating the nonlinear constitutive models for concrete and steel is implemented in a finite element program. Test specimens including a series of reinforced concrete beams and beam-column-slab connections of flat plates are analysed. Results confirm the effectiveness and accuracy of the layered procedure in predicting both flexural and shear cracking up to failure.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.10a
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• pp.323-328
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• 1995

This paper is experimental study to define the structural behaviors of reinforced flat plate under combined gravity and lateral loads. Specific objectives of this study reported herein are : (1) To study the behavior of a typical slab-column subassemblage under lateral loading. (2) To study the effects of vertical loads on slab-column lateral load behavior. (3) To investigate the post-failure behavior of slab-column connetios. To achieve these objectives, this study includes four tests of slab-column subassemblages that were made for 1/2 scale. Finally, Test results of this study show that the level of gravity load on the flat plate is one of the most important factors determining the lateral behavior of flat plate connections.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.101-102
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• 2017

This study was carried out as basic study to apply to construction site the HPC method which is being developed. The construction cost of HPC method was analyzed in comparison with conventional method (half slab method). With regard to research method, it was decided that data on construction work carried out by half slab method was analyzed. According to the results of study, in case of being applied to the construction work using a divided column, the number of columns was decreased. So, it was shown that member production cost, and transport and assemblage cost reduced. In case of being applied to construction work using an undivided column, the analysis showed that there was little difference in construction cost. Therefore, the analysis showed that, if HPC construction method was applied to large structure using a large column, the construction cost was reduced to some extent in comparison with conventional half slab method.

• Computers and Concrete
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• v.12 no.3
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• pp.351-375
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• 2013

Post-punching resistance of a flat slab can help redistribute the gravity loads and resist progressive collapse of a structure following initial damage. One important difficulty with accounting for the post-punching strength of a slab is the discontinuity that develops following punching shear. A numerical simulation technique is proposed here to model and evaluate post-punching resistance of flat slabs. It is demonstrated that the simulation results of punching shear and post-punching response of the model of a slab on a single column are in good agreement with corresponding experimental data. It is also shown that progressive collapse due to a column removal (explosion) can lead to punching failure over an adjacent column. Such failure can propagate throughout the structure leading to the progressive collapse of the structure. Through post-punching modeling of the slab and accounting for the associated discontinuity, it is also demonstrated that the presence of an adequate amount of integrity reinforcement can provide an alternative load path and help resist progressive collapse.

• Earthquakes and Structures
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• v.22 no.2
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• pp.203-218
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• 2022

In this paper, quasi-static tests were carried out on three prefabricated reinforced concrete column-steel beam (RCS) sub-assemblages with floor slabs and one comparison specimen without floor slab. The effects of axial compression and floor slab on the seismic performance were studied, and finite element simulations were conducted using ABAQUS. The results showed that the failure of prefabricated RCS sub-assemblages with floor occurred as a joint beam and column failure mode, while failure of sub-assemblages without floor occurred due to beam plastic hinge formation. Compared to the prefabricated RCS sub-assemblages without floor slab, the overall stiffness of the sub-assemblages with floor slab was between 19.2% and 45.4% higher, and the maximum load bearing capacity increased by 26.8%. However, the equivalent viscosity coefficient was essentially unchanged. When the axial compression ratio increased from 0.24 to 0.36, the hysteretic loops of the sub-assemblages with floor became fuller, and the load bearing capacity, ductility, and energy dissipation capacity increased by 12.1%, 12.9% and 8.9%, respectively. Also, the initial stiffness increased by 10.2%, but the stiffness degradation accelerated. The proportion of column drift caused by beam end plastic bending and column end bending changed from 35% and 46% to 47% and 36%, respectively. Comparative finite element analyses indicated that the numerical simulation outcomes agreed well with the experimental results.

• Journal of the Korea Institute of Building Construction
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• v.13 no.5
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• pp.482-490
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• 2013

Although the flat plate system is an efficient structural type due to the simplicity of its construction, the low story height, and the various plan design, the slab-column connections are vulnerable to punching shear failure from gravity load and eccentric shear failure from lateral load. To prevent the structure collapse, various construction methods of slab-column connection reinforcement are developed but none of these satisfies all of structural performance, economics, and constructability. This paper presents the reinforcement of slab-column connection with lattice bars. The structural performance is confirmed with the interior slab-column connection tests subjected to cyclic loading, and the economic feasibility is demonstrated from the structural design under the same condition with lattice bars, stud rails, and stirrups.

• Journal of the Earthquake Engineering Society of Korea
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• v.11 no.6
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• pp.23-32
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• 2007

This study developed an analytical model for predicting nonlinear behavior of PT flat plate frames having slab-column connections with and without slab bottom reinforcement passing through the column. The developed model can predict the failure sequence until punching failure occurs. For verifying the analytical model, the test results of PT flat plate slab-column connections were compared with the results of the analysis. Moreover, the results of static pushover test and shaking table test of 2 story PT flat plate frame were compared with analysis results. For evaluating seismic performance of PT flat plate frame, this study conducted nonlinear response history analysis of the 2 story PT flat plate frame with and without slab bottom reinforcement passing through the column under 1940 El Centro ground motion scaled to have pseudo spectral acceleration of 0.3, 0.5, and 0.7g at the fundamental period of the frame. This study observed that as ground motion is more intense, seismic demands for the frame having the connections without slab bottom reinforcement passing through the column are larger than those without slab bottom reinforcement.

• Computers and Concrete
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• v.22 no.1
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• pp.71-81
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• 2018

Introduction of prestressed concrete slabs based on post-tensioned (PT) method aids in constructing larger spans, more useful floor height, and reduces the total weight of the building. In the present paper, for the first time, simulation of 32 two-way PT slab-edge column connections is performed and verified by some existing experimental results which show good consistency. Finite element method is used to assess the performance of bonded and unbonded slab-column connections and the impact of different parameters on these connections. Parameters such as strand bonding conditions, presence or absence of a shear cap in the area of slab-column connection and the changes of concrete compressive strength are implied in the modeling. The results indicate that the addition of a shear cap increases the flexural capacity, further increases the shear strength and converts the failure mode of connections from shear rigidity to flexural ductility. Besides, the reduction of concrete compressive strength decreases the flexural capacity, further reduces the shear strength of connections and converts the failure mode of connections from flexural ductility to shear rigidity. Comparing the effect of high concrete compressive strengths versus the addition of a shear cap, shows that the latter increases the shear capacity more significantly.