• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.1-4
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• 2008

Flat plate slab has been widely used in high rise building for its remarkable advantages. However, Flat plate structures under lateral load are susceptible to punching shear of the slab-column connection. Exterior slab-column connections has an unsymmetrical critical section for eccentric shear of which perimeter is less than that of interior connection, and hence, around the connection, unbalanced moment and eccentric shear are developed by both gravity load and lateral loads. Therefore, exterior connections is susceptible to punching shear failure. For that reason, this study compare ACI 318-05 to CEB-FIP MC 90 that is based on experiment results and existing data of flat plate exterior connections. This study shows that compared to CEB-FIP MC 90 is more exact about eccentric shear stress, unbalanced moment and Both of all are not suitable in large column aspect ratio. Considering gravity shear ratio, These are suitable but design condition only consider gravity shear ratio. So these should be considered differences from change of design condition

• Structural Engineering and Mechanics
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• v.14 no.3
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• pp.307-330
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• 2002

This study aims at postulating a simple methodology for predicting the failure modes of monotonically loaded reinforced concrete beam-column joints. All the factors that affect the failure modes of joints are discussed in detail using an experimental database of monotonically loaded exterior beam-column joints. The relative contributions of the strut and truss mechanisms to joint shear strength are determined based on the test results. A simple design equation for the beam longitudinal reinforcement ratio for joints with low, medium and high amount of stirrups is developed. The factors influencing the failure modes of monotonically loaded exterior beam-column joints are investigated in detail. Design charts that predict the failure modes of exterior beam-column connections both with and without stirrups are developed. Experimental data are compared with the design charts. The results show that the simple methodology gives very accurate predictions of the failure modes.

• Journal of Korean Society of Steel Construction
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• v.10 no.1 s.34
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• pp.25-35
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• 1998

A moment connection of H beam-to-rectangular tube column with external stiffeners was proposed. A formula to predict the ultimate strength of the connection was derived based on the yield line mechanism. Experimental investigation was performed to determine the applicability of the connection type and the strength formula. The ultimate strengths computed by the formula agreed well with the experimental values.

• Steel and Composite Structures
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• v.21 no.6
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• pp.1251-1264
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• 2016

After observing relatively poor performance of bolted web-welded flange beam-to-column connections during 1994 Northridge earthquake, various types of connections based on two concepts of: (i) strengthening the connection; and (ii) weakening the beam ends were proposed. Among these modified or newly proposed connections, bolted T-stub connection follows the concept of strengthening. One of the connections with the idea of weakening the beam ends is reduced beam section (RBS). In this paper, finite element simulation is used to study the cyclic behavior of a new proposed connection developed by using a combination of both mentioned concepts. Investigated connections are exterior beam-to-column connections designed to comply with AISC provisions. The results show that moment capacity and dissipated energy of the new proposed connection is almost the same as those computed for a T-stub connection and higher than corresponding values for an RBS connection.

• Journal of the Korea Concrete Institute
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• v.26 no.2
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• pp.125-133
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• 2014

In this study, experimental research was carried out to investigate the seismic and structural performance of precast concrete exterior beam-column joints using bolt type connection and prestressing method. A total of five full-scale exterior beam-column joints were constructed and tested under reversed cyclic loading, controlled by displacement. Results of the test are as follows: Energy dissipation capacity and pinching phenomenon of PC beam-column joints showed disadvantageous behavior compared to RC beam-column joints. However, drift capacity of the PC joint was excellent. Also, yield mechanism concentrated on embedded nuts was suitable as an exterior beam-column joint of lateral load resistance frame. Additional application of prestressing method was also very effective to control excessive pinching and cracking in the joint region, and thus improved an overall seismic performance of the PC joint.

• Journal of the Korean Institute of Educational Facilities
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• v.16 no.3
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• pp.59-67
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• 2009

The intention of the study is to understand a characteristics of 'Campus core' in university campus and to verify the connection and hierarchy of exterior space in campus masterplan. This study concludes that 'Multi-nuclei structure', is where a single campus core was subdivided into several service cores, is an integral part of campus masterplan in process of expansion from campus core and the changing exterior space, by in-depth case analysis of Seoul Women's University Campus.

• Computers and Concrete
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• v.23 no.3
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• pp.203-215
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• 2019

Precast reinforced concrete structure (PRCS) consists of prefabricated members assembled at worksites and has more connections limitations in comparison with the equivalent in-situ reinforced concrete structure (IRCS). As a result of these limitations, PRCSs have less ductility in comparison with IRCSs. Recent studies indicate that the most noticeable failure in PRCSs have occurred in their connection zone. The objective of this study is introducing a type of precast beam-to-column connection (PBC) which in spite of being simple is of the same efficiency and performance as in-situ beam-to-column connection (IBC). To achieve this, the performance of proposed new PBC at exterior joint of a four story PRCS was analyzed by pseudo dynamic analysis and compared with that of IBC in equivalent IRCS. Results indicated that the proposed connection has even better performance in terms of strength, energy dissipation and stiffness, than that of IBC.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.8
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• pp.102-106
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• 2012

This paper was carried out to survey fire hazard and improvement at the drain pump in air-conditioners. Based on the results of analysis, the proposal of electrical accidents prevention and a construction improvement are as follows. A power connection of the drain pump has two types, an electrical outlet type and direct connection type at control board of air-conditioner. The electrical outlet types need a bulletin sign or education as malfunction of the drain pump include an additional accidents, current leakage and overflowing with water on the floor from breaker trip by exterior cause and breaker off by mistake of worker. On the other hand, the direct connection types prevent a power interruption as exterior cause, but it has some trouble, cut of ground cable and without protection device. Usually it doesn't work by electrician when air-conditioner and the drain pump power work. Therefore an education or countermeasures are recommended for not electrician. Generally malfunction of the drain pump causes accumulated materials into the tank. Even though the accumulated materials lead to an overheating and burning as failure of detector occur an idling, periodic inspection of the air-conditioner filter and the drain pump tank prevent the trouble.

• Journal of the Korea Concrete Institute
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• v.18 no.5 s.95
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• pp.595-602
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• 2006

An experimental study was conducted to investigate seismic behaviour of post-tensioned(PT) exterior slab-column connections used for the purpose to resist gravity loads only. For these, 2/3-scale, two PT post-tensioned exterior connections with two different tendon arrangement patterns and one conventional reinforced concrete(RC) exterior connection was tested under quasi-static, uni-directional reversed cyclic loading. During the lateral testing, gravity forces transferred to the column were kept constant to closely simulate a moment to shear ratio of a real building. One of the objectives of this study was to assess the necessity and/or the quantity of bottom bonded reinforcement needed to resist moment reversal which would occur under significant inelastic deformations of the adjacent lateral force resisting systems. The ACI 318 and 352 provisions for structural integrity were applied to provide the bottom reinforcement passing through the column for the specimens. Prior test results were also collected to conduct comparative studies for some design parameters such as the tendon arrangement pattern, the effect of post-tensioning forces and the use of bottom bonded reinforcement. Consequently, the impact of tendon arrangement on the seismic performance of the PT connection, that is lateral drift capacity and ductility, dissipated energy and failure mechanism, was considerable. Moreover, test results showed that the amount of bottom reinforcement specified by ACI 352. 1R-89 was sufficient for resisting positive moments arising from moment reversal under reversed cyclic loads. Shear strength of the tested specimens was more accurately predicted by the shear strength equation(ACI 318) considering the average compressive stress over the concrete($f_{pc}$) due to post-tensioning forces than that without considering $f_{pc}$.

• Journal of Industrial Technology
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• v.26 no.A
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• pp.29-38
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• 2006

Efficiency and universality which was the spirit of the modern age, had also an enfluence on our living environment. Various types of individual housing unit were developed and mass-produced. However, the exterior space in our city is a place for our social life and intermediate place to connect the private life of each individual to our society. For the people to adapt themselves well to their environment, it should be well organized which means it is clearly divided and integrated in a hierarchical order. To realize these conditions, adequate boundaries to divide each territory and entrances to connect each territory are two essential elements. One of the possible methods to realize these conditions can be found in korean traditional architecture where the exterior space has the same figural quality like buildings and is the center of the whole composition. Buildings, walls and colonnades are the elements to define space. Gates, pavilions, gabs between buildings and posts are the elements to symbolize the entrance connecting each space. Each exterior space is integrated to a whole composition. One is the gradual differentiation along the axis which is unique in korean traditional architecture. The other is the rectangular connection which is also found in the other area in the world. The results of this thesis are as follows. The exterior space in the housing area should have the figural quality. The elements to make boundaries defining exterior space are classified into horizontal elements such as low buildings and walls, and vertical elements such as tower-shape buildings which define space in a different way. The position of openings in a housing block affects the characteristic and openness of a exterior space. Various types of gates are used to decide the relationship between spaces.