• Steel and Composite Structures
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• v.8 no.3
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• pp.243-264
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• 2008

This paper details a testing facility ("NATURAL FIRE FACILITY") that allows closely-controlled experimental testing on full-scale sub-frames while reproducing the spatially transient temperature conditions measured in real fires. Using this test facility, an experimental investigation of six steel sub-frames under a natural fire was carried out at the Department of Civil Engineering of the University of Coimbra. The main objective of these tests was to provide insight into the influence of these connection types on the behaviour of steel sub-structures under fire. The experimental layout is defined by two thermally insulated HEA300 columns and an unprotected IPE300 beam with 5.7 m span, supporting a composite concrete slab. Beam-to-column connections are representative of the most common joint type used on buildings: welded joints and extended, flush and partial depth plate. Finally, the available results are presented and discussed: evolution of the steel temperature; development of displacements and local deformations and failure modes on the joints zone.

• Steel and Composite Structures
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• v.30 no.5
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• pp.433-441
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• 2019

The aim of this research is reinforcing of concrete with variety of fiber reinforced polymer (FRP) configurations and investigates the load capacity and ductility of these connections using an experimental investigation. Six scaled-down RC exterior joints were tested under moderately monotonic loads. The results show that, the shape of the FRP had a different effect on the joint capacity and the connection ductility coefficient. The greatest effect on increasing the ductility factor was seen in the sample where two reinforcement plates were used on both sides of the beam web (RCS5 sample). For the sample with the presence of FRP plates at the top and bottom of the beam (RCS3 sample), the ductility factor was reduced even the load capacity of this sample increased. Except for the RCS3 sample, the rest of the samples exhibited an increase in the ductility factor due to the FRP reinforcement.

• Journal of the Korea Concrete Institute
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• v.19 no.4
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• pp.401-409
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• 2007

The objective of this research is to provide better knowledge on the behavior of strong axis SRC column-RC beam joint, supported by experimental results, that can be broadly applicable to many structures. For this purpose, firstly literature reviews and field survey were made to classify the most commonly used for these types of joints. Then, experimental program was designed and performed including 6 SRC column-RC beam joint specimens designed with various joint details. Using the experimental results obtained from the quasi-static cyclic tests, structural performances of the joints such as hysteretic curves, maximum strength capacities, strength degradation beyond the maximum strength, ductilities, and energy dissipation capacities were investigated. Test results showed that specimens with wide beam shape (RCW-P, RCW-W, RCW-F) and T beam shape (RCT-W) showed better structural performances than the bracket type specimens (HBR-L, HBR-S). These specimens also revealed to have higher strength capacities than the nominal design strength. However, H beam bracket type specimens (HBR-L, HBR-S) need further study both analytically and experimentally to verify the reason for unexpected structural performances.

• Journal of the Korea Concrete Institute
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• v.22 no.3
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• pp.367-374
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• 2010

The transfer slab system is a structural system that transfers the loads from the upper shear wall structure to the lower columns. This is a costly system due to a very thick slab, and the relatively high cost can be mitigated by introducing voids in the slab. However, this system of flat plate containing voids is vulnerable to brittle failure caused by punching shear in vicinity of slab-column connection. Thus, the punching shear capacity of the void system is very important. However, the current code doesn't provide a clear design provision for the strength of slabs with a void section. In this study, experimental study was conducted to investigate the punching shear strength of the void slab system. The shear strength of the specimens was predicted by current code and previous researches. In result, the punching shear strength of the void system is determined as the least value calculated at critical section located a distance d/2 from the face of the column and the center of the void section using the effective area at critical section.

• Steel and Composite Structures
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• v.52 no.4
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• pp.405-418
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• 2024

To study the influence of different reduced beam section (RBS) on the mechanical performance of modular boltedwelded hybrid connection joints (MHCJs), this article uses ABAQUS to establish and verify the finite element model (FEM) of the test specimens on the basis of quasi-static test research. Based on, 14 joint models featuring different RBS are devised to evaluate their influence on seismic behavior, such as joint failure mode, bending moment (M)-rotation angle (θ) curve, ductility, and energy consumption. The results indicate that when the flange and web are individually weakened, they alleviate to some extent the concentrated stress of the core module (CM) and column end steel skeleton in the joint core area, but both increase the stress on the flange connecting plate (FCP). At the same time, the impact of both on seismic performance such as bearing capacity, stiffness, and energy consumption is relatively small. When simultaneously weakening the flange and web of the steel beam, forming plastic hinges at the weakened position of the beam end, significantly alleviated the stress concentration of the CM and the damage at the FCP, improving the overall deformation and energy consumption capacity of joints. But as the weakening size of the web increases, the overall bearing capacity of the joint shows a decreasing trend.

• Journal of the Korea Concrete Institute
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• v.20 no.4
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• pp.523-530
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• 2008

In structural design provision, maximum punching shear stress of slabs is prescribed as combined stress in direct shear occurred by gravity load and eccentric shear occurred by unbalanced moment. This means that the effect of unbalanced moment is considered to decide the punching shear stress. However, from the resistance capacity standpoint, the effect of unbalanced moment strength is not considered for deciding punching shear strength. In this paper, a model considering interrelation between unbalanced moment and punching shear was proposed. In the model, the relation between load effect and resistance capacity in unbalanced moment and punching shear was two-dimensionally expressed. Using the interrelation model, a method how unbalanced moment strength should be considered to decide the punching shear strength was proposed. Additionally, effective width enlargement factors for deciding the unbalanced moment strength of flat plates with shear reinforcements were proposed. The interrelation model proposed in this paper is very effective for the prediction of the behavior of slab-column connection because not only punching shear and unbalanced moment strengths but also failure modes of flat plates can be accurately predicted.