• Earthquakes and Structures
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• v.14 no.1
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• pp.73-84
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• 2018

Low cyclic loading tests are conducted on the steel reinforced recycled concrete (SRRC) column-steel (S) beam composite frame joints. This research aims to evaluate the earthquake damage performance of composite frame joints by performing cyclic loading tests on eight specimens. The experimental failure process and failure modes, load-displacement hysteresis curves, characteristic loads and displacements, and ductility of the composite frame joints are presented and analyzed, which shows that the composite frame joints demonstrate good seismic performance. On the basis of this finding, seismic damage performance is examined by using the maximum displacement, energy absorbed in the hysteresis loops and Park-Ang model. However, the result of this analysis is inconsistent with the test failure process. Therefore, this paper proposes a modified Park-Ang seismic damage model that is based on maximum deformation and cumulative energy dissipation, and corrected by combination coefficient ${\alpha}$. Meanwhile, the effects of recycled coarse aggregate (RCA) replacement percentage and axial compression ratio on the seismic damage performance are analyzed comprehensively. Moreover, lateral displacement angle is used as the quantification index of the seismic performance level of joints. Considering the experimental study, the seismic performance level of composite frame joints is divided into five classes of normal use, temporary use, repair after use, life safety and collapse prevention. On this basis, the corresponding relationships among seismic damage degrees, seismic performance level and quantitative index are also established in this paper. The conclusions can provide a reference for the seismic performance design of composite frame joints.

• Steel and Composite Structures
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• v.44 no.1
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• pp.33-47
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• 2022

This paper presents a finite element model for predicting the monotonic behaviour of bolted endplate joints connecting steel-concrete composite walls and steel beams. The demountable Hollo-bolts are utilised to facilitate the quick installation and dismantling for replacement and reuse. In the developed model, material and geometric nonlinearities were included. The accuracy of the developed model was assessed by comparing the numerical results with previous experimental tests on hollow/composite column-to-steel beam joints that incorporated endplates and Hollo-bolts. In particular, the Hollo-bolts were modelled with the expanded sleeves involved, and different material properties of the Hollo-bolt shank and sleeves were considered based on the information provided by the manufacture. The developed models, therefore, can be applied in the present study to simulate the wall-to-beam joints with similar structural components and characteristics. Based on the validated model, the authors herein compared the behaviour of wall-to-beam joints of two commonly utilised composite walling systems (Case 1: flat steel plates with headed studs; Case 2: lipped channel section with partition plates). Considering the ease of manufacturing, onsite erection and the pertinent costs, composite walling system with flat steel plates and conventional headed studs (Case 1) was the focus of present study. Specifically, additional headed studs were pre-welded inside the front wall plates to enhance the joint performance. On this basis, a series of parametric studies were conducted to assess the influences of five design parameters on the behaviour of bolted endplate wall-to-beam joints. The initial stiffness, plastic moment capacity, as well as the rotational capacity of the composite wall-to-beam joints based on the numerical analysis were further compared with the current design provision.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.04a
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• pp.246-249
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• 2004

When MWK (Multiaxial Warp Knitted Fabric) composites are applied for the structures, the connections of each component using mechanical fastening is needed. The local contact between the bolted joint and the composite laminates may induce high stress concentration or breakdown in the laminates for the mechanical joints. There for, it is strongly required to study the characteristics of mechanically joints of MWK composite laminates. In this study, stress analysis near the hole boundary of MWK composite laminate is conducted with various geometric factors under different loadings. In the case of multi-pin loaded MWK composite laminates, the results show that the types of loadings and geometric factors of mechanical joints have a significant influence on the joint performances.

• Steel and Composite Structures
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• v.37 no.1
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• pp.15-26
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• 2020

The top-and-seat angles with double web angles are commonly used in the design of beam-to-column joints in Asian and North American countries. The seismic behavior analysis of these joints with large cross-section size of beam and column (often connected by four or more bolts) is a challenge due to the effects from the relatively larger size of stiffened angles and the composite action from the adjacent concrete slab. This paper presents an experimental investigation on the seismic performance of exterior composite beam-to-column joints with stiffened angles under cyclic loading. Four full-scale composite joints with different configuration (only one specimen contain top angle in concrete slab) were designed and tested. The joint specimens were designed by considering the effects of top angles, longitudinal reinforcement bars and arrangement of bolts. The behavior of the joints was carefully investigated, in terms of the failure modes, slippage, backbone curves, strength degradation, and energy dissipation abilities. It was found that the slippage between top-and-seat angles and beam flange, web angle and beam web led to a notable pinching effect, in addition, the ability of the energy dissipation was significantly reduced. The effect of anchored beams on the behavior of the joints was limited due to premature failure in concrete, the concrete slab that closes to the column flange and upper flange of beam plays an significant role when the joint subjected to the sagging moment. It is demonstrated that the ductility of the joints was significantly improved by the staggered bolts and welded longitudinal reinforcement bars.

• Structural Engineering and Mechanics
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• v.24 no.3
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• pp.307-321
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• 2006

This paper is concerned with the behaviour of steel and concrete composite joints subjected to reversal of loading. Three cruciform composite joint specimens and one bare steel joint specimen were tested so that one side of the beam-to-column connection was under negative moment and another side under positive moment. The steelwork beam-to-column connections were made of bolted end plate with an extended haunch section. Composite slabs employing metal decking were used for all the composite joint specimens. The moment-rotation relationships for the joints were obtained experimentally. Details of the experimental observations and results were reported.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.14-17
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• 2004

A prefabricated composite hollow slab with perforated I-beams was suggested for the replacement of deteriorated concrete decks or the construction of new composite bridges with long-span slabs. Composite slabs with embedded I-beams have considerably higher stiffness and strength. For the application of prefabricated composite slabs to bridges, joints between slabs should satisfy the requirements of the ultimate limit state and the serviceability limit state. In this paper, three types of the detail for loop joints were selected and their structural performance in terms of strength and crack control was investigated through static tests on continuous composite slabs. A main parameter was the detail of the joint, such as an ordinary loop joint and loop joint with additional reinforcements. Even though there was no connection of the steel beams at the joints, the loop joints showed good performance in ultimate strength. In terms of crack control, the loop joint with additional reinforcements showed better performance. In ultimate limit state, the continuous composite slabs showed good moment redistribution and ductility.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.12 s.255
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• pp.1543-1550
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• 2006

Since the performance of joints usually determines the structural efficiency of composite structures, an extensive knowledge of the behavior of adhesive joints and the related effect on joint strength is essential for design purposes. In this study, the torque capacity of adhesive joints was predicted using the combined thermal and mechanical analyses when the adherend was a composite tube. A finite element analysis was performed to evaluate residual thermal stresses developed in the joint, and mechanical s stresses in the adhesive were calculated including both the nonlinear adhesive behavior and the behavior of composite tubes. Three different joint failure modes were considered to predict joint failure: interfacial failure, adhesive bulk failure, and adherend failure. The influence of the composite adherend stacking angle on the residual thermal stresses was investigated, and how the residual thermal stresses affect the joint strength was also discussed. Finally, the predicted results were compared with experimental results available in literature.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2002.05a
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• pp.167-172
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• 2002

During the operation of military aircraft, maintenance is divided into organizational, intermediate and depot maintenance. In the depot maintenance, after removal of major parts and removable doors, damage assessment is performed. Locating damage, charactering the damage and determining its extent, zoning the damage on the part being repaired and re-evaluation of the damaged area after damage removal. Repair joints are classified by bonded joints and bolted joints, depending on joining material. In this paper, repair method in aging aircraft is investigated and the possibility of application of copmposite patch is surveyed.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.04a
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• pp.94-97
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• 2005

The strength of aluminum 7075 and carbon composite hybrid joints was studied for adhesive, bolt, and the adhesive-bolt combined joints. Several hybrid joint specimens were tested to get the failure load and modes for three types of the joints. Adhesive Cytec EA9394S was used for aluminum and carbon bonding. Failure load of the adhesive-bolt combined joint was 94 % of the sum of the failure load of the separately bonded and bolted joints. Hybrid joint also showed more stable failure behavior than the simple adhesive or bolted joint.

• Composites Research
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• v.30 no.4
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• pp.229-234
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• 2017

Generally, joints are the weakest part in the composite structures. Composite joints can be classified into adhesive joints and mechanical joints, and mechanical joints are mainly used in areas less sensitive to environmental conditions. In this paper, the failure loads of composite mechanical joints with five different stacking angles are tested and predicted. Finite element analysis of mechanical joints were performed and failure loads were predicted by the FAI(Failure Area Index) method using Tsai-Wu and Yamada-Sun failure criteria, and the predicted failure loads were compared with experimental results. From the experiment and analysis, the failure loads of the mechanical joints were decreased as the ratio of 0 degree layer was low and they could be predicted within 13.03% using the FAI method and Yamada-Sun failure criteria.