• Korean Journal of Heritage: History & Science
• /
• v.55 no.4
• /
• pp.38-53
• /
• 2022

In this article, I have summarized and reviewed the concepts and terms surrounding the stamped construction technique, focusing on earthen walls in the Three Kingdoms period. This is because confusion is caused by defining the nature of the earthen walls by using various concepts and terms for each researcher regarding the substance and construction method of the earthen walls. The stamped earth method is a representative ancient civil engineering or construction technique in which a frame is made of plates to form a fortress wall, a fence, and the base of a building, and then soil or sand is poured into it layer by layer and then stamped with a bat to make it solid. Therefore, in order to prove that the earthen wall was built by the stamped earth method, evidence such as a narrow plate, a column for fixing it, long horizontal and vertical wood pieces to support the narrow plate, and traces of pounding the soil must be detected. However, in Korea, there are very few cases where such evidence has been fully excavated, so it is necessary to agree on how strictly the standards for the stamped earth method will be applied. The terms related to the stamped technique mobilized for the construction of the earthen walls were explained with actual examples by dividing the terms related to the concept into terms related to the principle and unit of the stamped plate, and the specific stamped technology. In particular, in Pungnabtoseong Earthen wall, a variety of typical and diverse methods of building the ancient stamped earthen wall were identified so that decisive data could be secured to understand the principles and techniques of the stamped earthen wall. In the future, a more general understanding of the stamped technique will be possible only when more evidence related to it is found in relics other than Pungnabtoseong Earthen wall.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2005.10a
• /
• pp.135-140
• /
• 2005

There are cofferdam and watertight wall to prevent of circulation or pollution during building of ocean structures like a dam and bridge in the harbors area and the sea. Inflow fluid and base of structure is important thing as one of the structural design factors for this interception wall like a cofferdam and watertight wall. In this study, it is revealed that at least 500 instantaneous velocity field data are required for ensemble average to get reliable turbulence statistics. The turbulent shear flow around a surface-mounted vertical wall was investigated by using the two-frame PIV(CACTUS 3.1) system and Mean velocity distributions have also been measured in the whole flow field.

• Journal of Korean Association for Spatial Structures
• /
• v.19 no.3
• /
• pp.33-40
• /
• 2019

A seismic isolation system is one of the most effective control devices used for mitigating the structural responses due to earthquake loads. This system is generally used as a type of base isolation system for low- and mid-rise building structures. If the base isolation technique is applied to high-rise buildings, a lot of problems may be induced such as the movement of isolation bearings during severe wind loads, the stability problem of bearings under large compression forces. Therefore, a mid-story isolation system was proposed for seismic protection of high-rise buildings. Residence-commerce complex buildings in Korea have vertical irregularity because shear wall type and frame type structures are vertically connected. This problem can be also solved by the mid-story isolation system. An effective analytical method using super elements and substructures was proposed in this study. This method was used to investigate control performance of mid-story isolation system for residence-commerce complex buildings subjected to seismic loads. Based on numerical analyses, it was shown that the mid-story isolation system can effectively reduce seismic responses of residence-commerce complex tall buildings.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2020.06a
• /
• pp.222-223
• /
• 2020

Recently, as the era of economic cooperation on the Korean Peninsula approaches, the role of the building sector, such as humanitarian reorganization of North Korean housing, is increasing. The purpose of this study is to find out the current location of North Korean housing standards through the North Korean Housing Survey. For the survey, a survey was conducted through 79 North Korean defectors. The main construction methods of North Korean housing are reinforced concrete, steel framed, wooden framed, masonry, and reinforced concrete walled and prefabricated. The residential environment satisfaction items consist of durability, waterproof, heating, ventilation, heat insulation, air tightness, mining, soundproofing, disaster safety, fire safety, and crime prevention. The result is as follows. The housing construction method in North Korea, which lived at that time, consisted of 21 people (30.88%) of reinforced concrete frames, 18 people (26.47%) of wooden frames, 17 people (25%) of masonry walls, 5 people of prefabricated structures (7.35%), and reinforced concrete. Two people (2.94%) were walled. Among these, the wooden frame type had the lowest satisfaction level for each item, and the reinforced concrete had a high level of dissatisfaction in the items of heating, confidentiality, and disaster safety, and the other item had a high level of satisfaction. The masonry wall type has a relatively high satisfaction level in terms of insulation, confidentiality, mining, and disaster safety.

• Earthquakes and Structures
• /
• v.23 no.3
• /
• pp.283-295
• /
• 2022

Seismic design codes permit the use of Equivalent Static Analysis of buildings considering torsional eccentricity e with dynamic amplification factors on structural eccentricity and some accidental eccentricity. Estimation of e in buildings is not addressed in codes. This paper presents a simple approximate method to estimate e in RC Moment Frame and RC Structural Wall buildings, which required no detailed structural analysis. The method is validated by 3D analysis (using commercial structural analysis software) of a spectrum of building. Results show that dynamic amplification factor should be applied on torsional eccentricity when performing Response Spectrum Analysis also. Also, irregular or mixed modes of oscillation arise in torsionally unsymmetrical buildings owing to poor geometric distribution of mass and stiffness in plan, which is captured by the mass participation ratio. These irregular modes can be avoided in buildings of any plan geometry by limiting the two critical parameters (normalised torsional eccentricity e/B and Natural Period Ratio 𝜏 =T_𝜃/T, where B is building lateral dimension, T_𝜃 uncoupled torsional natural period and T uncoupled translational natural period). Suggestions are made for new building code provisions.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.13 no.1
• /
• pp.35-43
• /
• 2009

Two types of piloti-type high-rise RC building structures having irregularity in the lower two stories were selected as prototypes, and nonlinear time history analysis was performed using OpenSees to verify the analysis technique and to investigate the seismic capacity of those buildings. One of the buildings studied had a symmetrical moment-resisting frame (BF), while the other had an infilled shear wall in only one of the exterior frames (ESW). A fiber model, consisting of concrete and reinforcing bar represented from the stress-strain relationship, was adapted and used to simulate the nonlinearity of members, and MVLEM (Multi Vertical Linear Element Model) was used to simulate the behavior of the wall. The analytical results simulate the behavior of piloti-type high-rise RC building structures well, including the stiffness and yield force of piloti stories, the rocking behavior of the upper structure and the variation of the axial stiffness of the column due to variation in loading condition. However, MVLEM has a limitation in simulating the abrupt increasing lateral stiffness of a wall, due to the torsional mode behavior of the building. The design force obtained from a nonlinear time history analysis was shown to be about $20{\sim}30%$ smaller than that obtained in the experiment. For this reason, further research is required to match the analytical results with real structures, in order to use nonlinear time history analysis in designing a piloti-type high-rise RC building.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.9 no.2
• /
• pp.45-50
• /
• 2009

The environment exploration is an essential process for indoor robots such as clean robot and security robot. Apartment house and office building has common frame structure, but internal arrangement of each room may be slightly different. So, it is more convenient to use a common frame map than to build a new map at every time the arrangement is changed. In this case, it is important to recognize invariant features such as wall, door and window. In this paper, an indoor mobile robot is implemented, and by using the laser scanner data and line segment histogram with respect to segment orientation and distance, an environment exploration method is presented and tested. This robot is fitted with a laser scanner, gyro sensor, ultra sonic sensor and IR sensor, and programed with C language.

• Structural Engineering and Mechanics
• /
• v.35 no.1
• /
• pp.19-35
• /
• 2010

This paper proposes a hybrid heuristic and criteria-based method of optimum design which combines the advantages of both the iterated simulated annealing (SA) algorithm and the rigorously derived optimality criteria (OC) for structural optimum design of reinforced concrete (RC) buildings under multi-load cases based on the current Chinese design codes. The entire optimum design procedure is divided into two parts: strength optimum design and stiffness optimum design. A modified SA with the strategy of adaptive feasible region is proposed to perform the discrete optimization of RC frame structures under the strength constraints. The optimum stiffness design is conducted using OC method with the optimum results of strength optimum design as the lower bounds of member size. The proposed method is integrated into the commercial software packages for building structural design, SATWE, and for finite element analysis, ANSYS, for practical applications. Finally, two practical frame-shear-wall structures (15-story and 30-story) are optimized to illustrate the effectiveness and practicality of the proposed optimum design method.

• Steel and Composite Structures
• /
• v.37 no.1
• /
• pp.91-98
• /
• 2020

Steel plate shear walls are recently used as efficient seismic lateral resisting systems. These lateral resistant structures are implemented to provide more strength, stiffness and ductility in limited space areas. In this study, the seismic behavior of the multi-story steel frames with steel plate shear walls are investigated for buildings with 4, 8, 12 and 16 stories using verified computational modeling platforms. Different number of steel moment bays with distinctive lengths are investigated to effectively determine the deflection amplification factor for low-rise and high-rise structures. Results showed that the dissipated energy in moment frames with steel plates are significantly related to the inside panel. It is shown that more than 50% of the dissipated energy under various ground motions is dissipated by the panel itself, and increasing the steel plate length leads to higher energy dissipation capability. The deflection amplification factor is studied in details for various verified parametric cases, and it is concluded that for a typical multi-story moment frame with steel plate shear walls, the amplification factor is 4.93 which is less than the recommended conservative values in the design codes. It is shown that the deflection amplification factor decreases if the height of the building increases, for which the frames with more than six stories would have less recommended deflection amplification factor. In addition, increasing the number of bays or decreasing the steel plate shear wall length leads to a reduction of the deflection amplification factor.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.19 no.5
• /
• pp.229-238
• /
• 2015

For small-size reinforce-concrete buildings, Midas Gen, OpenSees, and Perform-3D, which are structural analysis programs that are most popularly used at present, were applied for nonlinear static pushover analysis, and then difference between those programs was analyzed. Example buildings were limited to 2-story frames with irregular shaped walls. Analysis result showed that there were more differences than for frames only and frames with rectangular walls, but it was not so significant. Nevertheless, the capacity curve were different in some buildings, which is attributed to shape and location of walls, and feature of the analysis program. Especially, selection of automatic or manual input in Midas Gen, or nonlinear wall elements in Perform3D can affect the capacity curve and performance of the buildings. Therefore, the program users should understand the feature of the program well, and then conduct performance assessment. The result of this study is limited to low-story buildings so that it should be noted that it is possible to get different results for mid- to high-rise buildings.