• Structural Engineering and Mechanics
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• v.56 no.1
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• pp.67-83
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• 2015

The load transfer mechanism and load-bearing capacity of cast steel joints for H-shaped beam to square tube column connection are studied based on the deformation compatibility theory. Then the monotonic tensile experiments are conducted for 12 specimens about the cast steel joints for H-shaped beam to square tube column connection. The findings are that the tensile bearing capacity of the cast steel joints for beam-column connection depends on the ring of cast steel stiffener. The tensile fracture happens at the ring of the cast steel stiffener when the joint fails. The thickness of square tube column has little influence on the bearing capacity of the joint. The square tube column buckles while the joint without concrete filled, but the strength failure happens for the joint with concrete filled column. And the length of welding connection between square tube column and cast steel stiffener has little influence on the load-bearing capacity of the cast steel joint. Finally it is shown that the load-bearing capacity of the joints for H-shaped beam to concrete filled square tube column connection is larger than that of the joints for H-shaped beam to square tube column connection by 10% to 15%.

• Steel and Composite Structures
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• v.11 no.5
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• pp.375-390
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• 2011

Composite beam, which combined the material characteristic of the steel and concrete, has been widely used in the construction of various building and bridge system. For the effective application of the composite beam, the composite action on the composite interface between the concrete element and the steel element should be achieved by shear connectors. The behavioral characteristics of composite beam are related with the degree of interaction and the degree of shear connection according to the shear strength and shear stiffness of the stud shear connectors. These two concepts are also affected by the number of installed shear connector and the strength of composite materials. In this study, experimental and analytical evaluations of the degree of shear connection affected by stud diameter were conducted, and the relationship between structural behavior and the degree of shear connection was verified. The very small difference among the ultimate loads of the specimens depending on the change of the degree of connection was possibly because of the dependence of the ultimate load on the characteristic of plastic moment of the composite beam.

• Structural Engineering and Mechanics
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• v.57 no.5
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• pp.785-808
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• 2016

An innovative Reduced Beam Section (RBS) connection, called Tubular Web RBS connection (TW-RBS), has been recently introduced and its performance has been numerically investigated in some earlier studies. The TW-RBS connection is a kind of accordion-web RBS connection in which part of the flat web of the beam is replaced by a steel tube at the expected region of the plastic hinge. This paper presents experimental results of three TW-RBS connections under cyclic loading. Obtained results indicated that TW-RBS reduces contribution of the beam web to the whole moment strength and creates a ductile fuse far from components of the beam-to-column connection. Besides, TW-RBS connection can increase story drift capacity up to 9% in the case of shallow beams which is much more than those stipulated by the current seismic codes. Based on the experimental results, the tubular web in the plastic hinge region improves lateral-torsional buckling stability of the beam such that only local buckling of the beam flange at the center of the reduced section was observed during the tests. In order to achieve a better understanding, behavior of all TW-RBS specimens are also numerically investigated and compared with those of experimental results.

• Journal of the Korean Society of School Health
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• v.30 no.3
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• pp.306-316
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• 2017

Purpose: The purpose of this study was to investigate the operational status and operational problems of health promoting model schools, particularly of the large-sized elementary schools in urban areas. Methods: The study analyzed the data of 14 large-sized elementary schools in urban areas selected from 85 health promoting model schools, an initiative led by the Ministry of Education from 2012 to 2014. Results: The study examined the operation process of health promoting schools in five stages; system development, needs survey & current status survey, school health policy development, program development & execution, and evaluation. In addition, the study discovered three key factors in operating health promoting schools and examined the status of each factor; connection with the curriculum, connection with the community, and consensus among members. Four problems were identified as operational problems: lack of research on faculty health issues, school physical environment and community resources, inadequate presentation of performance indicators, no close coordination in core task development and lack of linkage with the curriculum. Conclusion: It turned out the concept of health promoting school suggested by WHO was relatively faithfully realized in this study. Compared to small-sized elementary schools in rural areas, health promoting schools in this study showed better aspects overall. The connection with the community was good, but the connection with the curriculum was poor.

• Structural Engineering and Mechanics
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• v.49 no.1
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• pp.23-40
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• 2014

In this article, using finite element method of analysis (FEM), behavior of the endplate moment connection subjected to axial force and bending moment is investigated. In the FEM model, all the nonlinear characteristics such as material, geometry, as well as contact have been included. First, in order to verify the numerical model of the connection, an analysis of the endplate moment connection conducted without the application of the axial force. Results obtained from FEM indicating a close and good correlation with the experimental results. Then to investigate the influence of the axial forces, the connections subjected to axial forces as well as the bending moment are analyzed. To observe the overall effect of these actions, the momentaxial force interaction diagrams are drawn. It is observed that the presence of axial force even in a small value can change the behavior of the connection significantly. It is also shown that the axial forces can alter the failure mode of the connection; and therefore it could result in a different than the predicted moment capacity of the connection.

• Steel and Composite Structures
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• v.36 no.5
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• pp.493-506
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• 2020

The load-slip relationship of the shear connection is an important parameter in design and analysis of composite structures. In this paper, a load-slip curve prediction method of the shear connection based on the artificial neural networks (ANNs) is proposed. The factors which are significantly related to the structural and deformation performance of the connection are selected, and the shear stiffness of shear connections and the transverse coordinate slip value of the load-slip curve are taken as the input parameters of the network. Load values corresponding to the slip values are used as the output parameter. A twolayer hidden layer network with 15 nodes and 10 nodes is designed. The test data of two different forms of shear connections, the stud shear connection and the perforated shear connection with flange heads, are collected from the previous literatures, and the data of six specimens are selected as the two prediction data sets, while the data of other specimens are used to train the neural networks. Two trained networks are used to predict the load-slip curves of their corresponding prediction data sets, and the ratio method is used to study the proximity between the prediction loads and the test loads. Results show that the load-slip curves predicted by the networks agree well with the test curves.

• Steel and Composite Structures
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• v.39 no.2
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• pp.135-148
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• 2021

Hollow structural section (HSS) columns have been increasingly popular due to their structural and architectural merits. However, practical difficulty lies in developing proper connections. The through-diaphragm connections are considered as suitable connection type that is widely adopted in Asian countries. However, the stress concentration occurs at the location connecting through-diaphragm and steel beam. Furthermore, the actual load path from the beam flange is not uniformly transferred to the HSS column as conventionally assumed. In this paper, tensile tests were further conducted on three additional specimens with beam flange plate to evaluate the load versus displacement response. The load-displacement curves, yield and ultimate capacity, ductility ratio were obtained. Furthermore, the strain development at different loading levels was discussed comprehensively. It is shown that the studied connection configuration significantly reduces the stress concentration. Meanwhile, simplified trilinear load-displacement analytical model for specimen under tensile load was presented. Good agreement was found between the theoretical and experimental results.

• Journal of the Earthquake Engineering Society of Korea
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• v.28 no.1
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• pp.47-57
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• 2024

Recently, in newly constructed apartment buildings, the exterior wall structures have been characterized by thinness, having various openings, and a significantly low reinforcement ratio. In this study, a nonlinear finite element analysis was performed to investigate the crack damage characteristics of the exterior wall structure. The limited analysis models for a 10-story exterior wall were constructed based on the prototype apartment building, and nonlinear static analysis (push-over analysis) was performed. Based on the finite element (FE) analysis model, the parametric study was conducted to investigate the effects of various design parameters on the strength and crack width of the exterior walls. As the parameters, the vertical reinforcement ratio and horizontal reinforcement ratio of the wall, as well as the uniformly distributed longitudinal reinforcement ratio and shear reinforcement ratio of the connection beam, were addressed. The analysis results showed that the strength and deformation capacity of the prototype exterior walls were limited by the failure of the connection beam prior to the flexural yielding of the walls. Thus, the increase of wall reinforcement limitedly affected the failure modes, peak strengths, and crack damages. On the other hand, when the reinforcement ratio of the connection beams was increased, the peak strength was increased due to the increase in the load-carrying capacity of the connection beams. Further, the crack damage index decreased as the reinforcement ratio of the connection beam increased. In particular, it was more effective to increase the uniformly distributed longitudinal reinforcement ratio in the connection beams to decrease the crack damage of the coupling beams, regardless of the type of the prototype exterior walls.

• Computers and Concrete
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• v.16 no.1
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• pp.163-178
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• 2015

Due to the increase of the use of precast concrete structures in multistory buildings, this paper deals with the behavior of an specific type of beam-column connection used in this structural system. The connection is composed by concrete corbels, dowels and continuity bars passing through the column. The study was developed based on the experimental and numerical results. In the experimental analysis a full scale specimen was tested and for numerical study, a 3D computational model was created using a finite element analyze (FEA) software, called DIANA. The comparison of the results showed a satisfactory correlation between loading versus displacement curves.

• Computers and Concrete
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• v.16 no.3
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• pp.381-397
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• 2015

Connections are the most important regions in a structural system especially for buildings in seismic zones. In R.C. structures due to large dimensions of members and lack of cognition of the stress distribution in a connection, reaching a comprehensive understanding of the connection behaviors becomes more complicated. The shear wall-to-floor slab connections in lateral load resisting systems have a potential weakness in transferring loads from slabs to shear walls which might change the path of load transformation to shear walls. This paper tries to investigate the effects of seismic load combinations on the behavior of slabs at their connection zones with the shear walls. These connection zones naturally are the most critical regions of the slabs in RC buildings. The investigation carried on in a simulated environment by considering three different structures with different shear wall layout. The final results of our study reveal that layout of shear walls in a building significantly affects the magnification of forces developed at the shear wall-floor slab connections.