• Steel and Composite Structures
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• v.29 no.1
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• pp.1-22
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• 2018

Multi-storey precast concrete skeletal structures are assembled from individual prefabricated components which are erected on-site using various types of connections. In the current design of these structures, beam-to-column connections are assumed to be pin jointed. Welded plate beam to-column connections have been used in the precast concrete industry for many years. They have many advantages over other jointing methods in component production, quality control, transportation and assembly. However, there is at present limited information concerning their detailed structural behaviour under bending and shear loadings. The experimental work has involved the determination of moment-rotation relationships for semi-rigid precast concrete connections in full scale connection tests. The study reported in this paper was undertaken to clarify the behaviour of such connections under symmetrical vertical loadings. A series of full-scale tests was performed on sample column for which the column geometry and weld arrangements conformed with successful commercial practice. Proprietary hollow core slabs were tied to the beams by tensile reinforcing bars, which also provide the in-plane continuity across the connections. The strength of the connections in the double sided tests was at least 0.84 times the predicted moment of resistance of the composite beam and slab. The secant stiffness of the connections ranged from 0.7 to 3.9 times the flexural stiffness of the attached beam. When the connections were tested without the floor slabs and tie steel, the reduced strength and stiffness were approximately a third and half respectively. This remarkable contribution of the floor strength and stiffness to the flexural capacity of the joint is currently neglected in the design process for precast concrete frames. In general, the double sided connections were found to be more suited to a semi-rigid design approach than the single sided ones. The behaviour of double sided welded plate connection test results are presented in this paper. The behaviour of single sided welded plate connection test results is the subject of another paper.

• Steel and Composite Structures
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• v.29 no.5
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• pp.603-622
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• 2018

Precast concrete structures are erected from individual prefabricated components, which are assembled on-site using different types of connections. In the present design of these structures, beam-to-column connections are assumed pin jointed. Bolted billet beam to-column connections have been used in the precast concrete industry for many years. They have many advantages over other jointing methods in component production, quality control, transportation and assembly. However, there is currently limited information concerning their detailed structural behaviour under vertical loadings. The experimental work has involved the determination of moment-relative rotation relationships for semi-rigid precast concrete connections in full-scale connection tests. The study reported in this paper was undertaken to clarify the behaviour of such connections under symmetrical vertical loadings. A series of full-scale tests was performed on sample column for which the column geometry and bolt arrangements conformed to successful commercial practice. Proprietary hollow core floor slabs were tied to the beams by 2T25 tensile reinforcing bars, which also provide the in-plane continuity across the connections. The contribution of the floor strength and stiffness to the flexural capacity of the joint is currently neglected in the design process for precast concrete frames. The flexural strength of the connections in the double-sided tests was at least 0.93 times the predicted moment of resistance of the composite beam and slab. The secant stiffness of the connections ranged from 0.94 to 1.94 times the flexural stiffness of the attached beam. In general, the double-sided connections were found to be more suited to a semi-rigid design approach than the single sided ones. The behaviour of double sided bolted billet connection test results are presented in this paper. The behaviour of single sided bolted billet connection test results is the subject of another paper.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.10a
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• pp.317-322
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• 1995

This study is to examine the usefulness in using precast girder-infilled steel tube column in reinforced concrete structures through the analysis of the test results, in order to develope the new composite structural system using precast girder-Infilled steel tube column, The variables of specimen are strength of concrete, the numble of hoops, the form of beam-column The variables of specimen are strength of concrete, the number of hoops, the form of beam-column joints. By raising strength of concrete and incresing number of hoops in beam-column joint, it becomes clear to take similar structure capacity to monolithic structures.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.425-428
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• 2004

Nonlinear finite element analysis is conducted to predict the structural behavior of precast concrete column and steel beam connected by using bolted connections. The Nonlinear FEM program is based on the modified compression field theory which has good accuracy in the concrete structures. The link element is properly used to model the discontinuity between precast concrete column and steel beam. Predictions from the proposed model are compared with experimental results and it is concluded that structural behaviors of the composite structures, such as strength capacity, crack pattern and failure mode, can be predicted quite successfully.

• Computers and Concrete
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• v.24 no.3
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• pp.223-236
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• 2019

Experience of previous earthquakes shows that a considerable portion of concrete precast buildings sustain relatively large damages especially at the beam-column joints where the damages are mostly caused by bar slippage. Precast concrete buildings have a kind of discontinuity in their beam-column joints, so reinforcement details in this area is too important and have a significant effect on the seismic behavior of these structures. In this study, a relatively simple and efficient nonlinear model is proposed to simulate pre- and post-elastic behavior of the joints in usual practice of precast concrete building. In this model, beam and column components are represented by linear elastic elements, dimensions of the joint panel are defined by rigid elements, and effect of slip is taken into account by a nonlinear rotational spring at the end of the beam. The proposed method is validated by experimental results for both internal and external joints. In addition, the seismic behavior of the precast building damaged during Bojnord earthquake 13 May 2017, is investigated by using the proposed model for the beam-column joints. Damage unexpectedly inducing the precast building in the moderate Bojnord earthquake may confirm that bearing capacity of the precast building was underestimated without consideration of joint behavior effect.

• Journal of the Korean GEO-environmental Society
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• v.24 no.12
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• pp.13-18
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• 2023

Cast-in-place concrete lining is commonly used in tunnel lining, but cast-in-place concrete lining has problems with construction and quality control. Precast segment lining is being used to solve these problems. In general, precast segment lining is known to have improved durability and easy maintenance such as rehabilitation of structures. This study compared the durability of 22 tunnel linings constructed with precast segments or cast-in-place reinforced concrete.

• Steel and Composite Structures
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• v.10 no.1
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• pp.1-21
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• 2010

As an alternative for conventional structures for tall buildings, a hybrid lateral load resisting structure has been designed, enabling the assembly of tall buildings directly from a truck. It consists of steel frames with discretely connected precast concrete infill panels provided with window openings. Besides the stiffening and strengthening effect of the infill panels on the frame structure, economical benefits may be derived from saving costs on materials and labour, and from reducing construction time. In order to develop design rules for this type of structure, the hybrid infilled frame has recently been subjected to experimental and numerical analyses. Ten full-scale tests were performed on one-storey, one-bay, 3 by 3 m infilled frame structures, having different window opening geometries. Subsequently, the response of the full-scale experiments was simulated with the finite element program DIANA. The finite element simulations were performed taking into account non-linear material characteristics and geometrical non-linearity. The experiments show that discretely connected precast concrete panels provided with a window opening, can significantly improve the performance of steel frames. A comparison between the full-scale experiments and simulations shows that the finite element models enable simulating the elastic and plastic behaviour of the hybrid infilled frame.

• Earthquakes and Structures
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• v.2 no.3
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• pp.297-321
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• 2011

The seismic design of a two-storey precast reinforced-concrete building structure equipped with viscous dampers is presented in this paper with twofold purpose. The first goal is to verify the applicability of a practical procedure for the identification of the mechanical characteristics of the viscous dampers which allow to achieve target performance levels, originally proposed by the authors for moment-resisting building frames, also with reference to "pendular" structures. The second goal is to investigate the effectiveness of the use of viscous dampers (as compared with traditional lateral-resisting stiff braces) for the seismic design of precast not moment-resisting concrete structures.

• Journal of the Korea institute for structural maintenance and inspection
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• v.3 no.3
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• pp.261-268
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• 1999

The seismic performance of precast concrete panel structures tested previously has been evaluated in this paper. Hysteretic curves of test specimens are idealized to elasto-plastic curves to get reliable yielding and ultimate displacements. For the idealized curves, ductility and energy dissipation capacity of specimens have been evaluated using a few guide lines. In addition, the strength capacity of specimens is checked for the strength demand caused by the design earthquake load including overturning moment effects. The result shows while the strength of specimen with joint box for vertical continuity is little bit lower than that of specimen connected by welding, the ductility of the former is higher than that of the latter. The energy dissipation ratios of PC specimens are ranged from 83% to 96% of that of Re specimen and the average of those are shown 90%.

• Journal of the Korean Society for Advanced Composite Structures
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• v.6 no.2
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• pp.8-16
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• 2015

Prestressed concrete (PSC) is a method in which prestressed tendon is placed inside and/or outside the reinforced concrete member and the compressive force applied to the concrete in advance to enhance the engineering properties of concrete member which is weak under tension. In this paper we suggested the precast PSC girder assembled with segments of portable size and weight at the factory. The segments of precast PSC girder will be delivered and assembled as a unit of PSC girder at the site. Consequently, we suggested new-type of precast segmented PSC girder with different shapes of segment cross-section (i.e., I-shape, Box-shape). To mitigate the problems associated with the field splice between the segments of precast PSC girder anchor system is attached near the neutral axis of the girder and relatively uniform compression throughout the girder cross-section is applied. Prior to the experimental investigation, analytical investigation on the structural behavior of precast PSC girder was performed and the serviceability (deflection) and safety (strength) of the girder were confirmed. In addition, 4-point bending test on the girder was conducted to investigate the structural performance under bending. From the experimental investigation, it was found that the precast PSC girder spliced with 3 and 5 segments has sufficient in serviceability and safety conditions and it was also observed that the point where the segments spliced has no defects and the girder behaves as a unit.