• Title/Summary/Keyword: Architectural Engineering Design

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Wave Passage Effect on the Seismic Response of a Building considering Bedrock Shear Wave Velocity (기반암의 전단파속도를 고려한 지진파의 통과시차가 건물의 지진거동에 미치는 영향)

  • Kim, Yong-Seok
    • Journal of the Earthquake Engineering Society of Korea
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    • v.18 no.2
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    • pp.89-94
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    • 2014
  • Spatial variations of a seismic wave are mainly wave passage and wave scattering. Wave passage effect is produced by changed characteristics of exciting seismic input motions applied to the bedrock. Modified input motions travel horizontally with time differences determined by apparent shear wave velocity of the bedrock. In this study, wave passage effect on the seismic response of a structure-soil system is investigated by modifying the finite element software of P3DASS (Pseudo 3-Dimensional Dynamic Analysis of a Structure-soil System) to apply inconsistent (time-delayed) seismic input motions along the soft soil-bedrock interface. Study results show that foundation size affected on the seismic response of a structure excited with inconsistent input motions in the lower period range below 0.5 seconds, and seismic responses of a structure were decreased considerably in the lower period range around 0.05 seconds due to the wave passage. Also, shear wave velocity of the bedrock affected on the seismic response of a structure in the lower period range below 0.3 seconds, with significant reduction of the seismic response for smaller shear wave velocity of the bedrock reaching approximately 20% for an apparent shear wave velocity of 1000m/s at a period of 0.05 seconds. Finally, it is concluded that wave passage effect reduces the seismic response of a structure in the lower period range when the bedrock under a soft soil is soft or the bedrock is located very deeply, and wave passage is beneficial for the seismic design of a short period structure like a nuclear container building or a stiff low-rise building.

Improvement Model of Defect Information Management System for Apartment Buildings (공동주택에 대한 하자정보 관리시스템의 개선 모델)

  • Kang, Hyunwook;Park, Yangho;Kim, Yongsu
    • Korean Journal of Construction Engineering and Management
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    • v.20 no.4
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    • pp.13-21
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    • 2019
  • The purpose of this study is to suggest an Improvement Model of defect information management system. The improvement model adapts methods for the residents to input defect information correctly and share to defect information with construction company. The adapted research method is review for existing defect information management system and suggested for data flow diagram of improvement model. The results of this study are as follows: The basic design of the information input window of the defect information management system for connecting with big data was made. And 5 point scale was applied to evaluate the convenience, simplicity, accuracy, necessity, and usability of the improvement model. It is evaluated that the economic effect caused by using the improvement model is saved by about 151 million KRW compared to the existing method. The Improvement model is used utilize big data in correct defect management and decision making.

Experimental Study on the Setting Time and Compressive Strength of Nano-Micro Pozzolanic Binders as Cement Composites (포졸란 혼화재의 입자 크기 및 비표면적에 따른 응결시간 발현 및 압축강도 특성 평가)

  • Kim, Won-Woo;Yang, Keun-Hyeok
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.10 no.3
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    • pp.269-275
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    • 2022
  • In this study, the setting time and compressive strength of cement paste composites applied with nano-micro pozzolanic binders were experimental analyzed. The pozzolanic binder was reduced initial and final setting time and the compressive strength was increased. Micro silica was effective in decrease the initial setting and final setting time and impressing the compressive strength. When two or more cement binders were used, the using of silica fume and a small amount of nano silica at reduced the setting time to 62-64 % to OPC cement and the compressive strength was increased to 117 %. A small amount of mixing the nano silica was effect to pore filling and pozzolanic activation. However, the addition of a chemical admixture should be considered when mixing table design because pozzolanic binders high specific surface area causes a decrease in cement composites flow.

Verification of External Magnetization based EM Technique for Diagnosing Residual Tensile Stress in Aged PSC Structures (노후 PSC 구조물의 잔여 긴장 응력 진단을 위한 외부 자화 EM 기법 검증)

  • Soon-Jeon Park;Sehwan Park;Jaehoon Choi;Kyo-Young Jeon;Junkyeong Kim
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.36 no.4
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    • pp.251-257
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    • 2023
  • This study entailed an investigation of a tensile stress measurement method for prestressed concrete (PSC) tendons by utilizing external magnetization. The target of this study are PS structures that have been constructed and in use. An optimal external magnetization based elasto-magnetic (EM) sensor was designed using finite element analysis considering various factors, such as coil arrangement and size, that could influence the PS tendons inside the PSC girder. The residual tensile stress resulting from the external magnetization of the girder was then determined. Further, theoretical verification was performed using the numerical and material data used in the finite element analysis for sensor design. The calculated values of strength of magnetization at the target location were matched with the finite element analysis results. Thus, the designed sensor and the feasibility of magnetizing the tendons inside the PSC I-girder using an EM sensor were validated.

Evaluating the impact of urban multifunctional walls on pedestrian wind comfort on street sidewalks (Case study: Tabriz city)

  • Parinaz Badamchizadeh;Paria Saadatjoo;Majid Ahmadlouydarab;Guoqiang Zhang
    • Wind and Structures
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    • v.39 no.3
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    • pp.223-242
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    • 2024
  • Wind comfort in cold climates is one of the most essential factors for urban planners. This issue is particularly important for sidewalks that are in line with the prevailing wind flow and surrounded by high-rise buildings. Imam Street near the University Square in Tabriz is one of the passages that struggle with uncomfortable wind speeds. The aim of this study is to investigate the role of sidewalk walls on pedestrian wind comfort. These multifunctional walls not only serve as street furniture, but also reduce wind speed at pedestrian level. In this work, all simulations are performed using the RWIND tool and validated by wind tunnel experiments at the Architectural Institute of Japan. The main objective of this study is to evaluate the effects of the angle, height and spacing of the walls on wind attenuation at pedestrian level. The results show the effect of multifunctional walls on pedestrian-level wind mitigation. By rotating the windbreak walls from 0 to 60 degrees along the street, the average wind speed decreases by 30% to 46% compared to a situation without this type of wall. Increasing the wall height from 1.5 to 2 meters reduces the urban wind speed by 39-46%. However, increasing the distance between the sidewalk walls from 3.5-9.5 meters reduces the speed in the models from 46% to 32.7%. Finally, it has been demonstrated that sidewalk walls with a height of 2 meters, a rotation angle of 60° and a distance of 3.5 meters are the optimal choice for wind attenuation at pedestrian level.

Experimental and Analytical Study on the Steel Beam bonded with CFRP Strip (레진으로 접착 보강한 강재보의 거동)

  • Sung, Ikhyun
    • Journal of the Society of Disaster Information
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    • v.13 no.1
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    • pp.81-88
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    • 2017
  • In this paper, the behaviour of composite steel-CFRP members is studied experimentally and using FE-analysis. The use of advance composite materials in construction for repair and rehabilitation has become a frequent used method in the last decade. FRP composites have many advantages over the traditional technique of steel bonding for a number of reasons: 1. Composites add little or no additional weight to a building, eliminating the need for costly foundation strengthening. 2. FRP composites are very thin (1.2mm to 1.4mm). So there is no loss of floor space and negligible effect over the architectural aspect. 3. FRP composites do not corrode, this makes it long lasting. However, the method is yet to become a mainstream application due to a number of economical and design related issues. Brittle debonding failure, aging effect on bonding, broad based awareness and proper design guidelines are the main concern for future research works. This paper is focused on the ultimate load carrying capacity of the CFRP-strengthened beams and their effect on the deflection and failures modes by varying the amount of CFRP content.

Comparative Study of the System for Decentralized Rainwater Management in Korea and Germany (한국과 독일의 분산식 빗물관리를 위한 제도 비교 연구)

  • Han, Young-Hae;Lee, Tae-Goo
    • Journal of the Korean Institute of Landscape Architecture
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    • v.34 no.4 s.117
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    • pp.84-95
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    • 2006
  • This study begins by examining the reason for the lack of urban planning that takes the water cycle into consideration. While there are institutions that support environmentally friendly development or smooth water circulation, these designs are not reflected in planning nor in the real world. After reviewing foreign case studies, policy suggestions and possible policy implications for Korea are derived. In Korea, there is not a sufficient level of relevant laws or institutions systematically established to make it possible to deal with rainwater in a decentralized way. Instead, facility standards or guidelines are considered separately for the control of water and for preventing natural disasters. And even though an environmentally friendly approach is stipulated in relevant laws in terms of spatial planning, there are no planning systems or implementation tools to actualize this kind of approach. The factors that make decentralized rainwater management possible in urban planning are analyzed based on the case study of Germany. Germany requires developers to plan in order to achieve ecological urban development. In addition, as a detailed implementation tool to promote conservation of the water cycle, the law provides for various kinds of measures such as restrictions on the proportion of impervious surface area according to the use of the land, required compensation measures for environmental degradation following development, introduction of a fee for rainwater runoff and the establishment of ecological landscape planning. The actual reason these measures can be implemented however is the provision of planning guidelines and design criteria for rainwater utilization, absorption and containment, and the construction of a database for various environmental information.

Seismic Behavior of Columns in Ordinary and Intermediate Moment Frames (보통과 중간 모멘트 골조 기둥의 내진거동 비교)

  • Han Sailg-Whan
    • Journal of the Korea Concrete Institute
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    • v.17 no.1 s.85
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    • pp.51-58
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    • 2005
  • Moment frames have been widely used in building construction. In current design codes, concrete moment frames are classified into ordinary, intermediate, and special moment resisting concrete frames (OMRCF, IMRCF, SMRCF)). The objective of this study is to investigate the seismic behavior of columns in ordinary moment resisting concrete frames (OMRCF) and intermediate moment resisting concrete frames (IMRCF). For this purpose 3 story OMRCF and IMRCF buildings were designed and detailed in compliance to ACI 318 (2002) and KCI (1999). In this study the buildings were assumed to be located in seismic zone 1 classified by UBC (1997). This study considered the columns in the 1st story since these columns shall resist the largest axial and lateral forces during an earthquake. Eight 2/3 scale column specimens were made for representing the upper part and lower part of exterior and interior columns of the OMRCF and the IMRCF Quasi-static reversed cyclic loading was applied to each specimen with a constant or varying axial load. Test results show that seismic behaviors of columns are influenced by existence of lap splices, axial force levels, and lateral reinforcement at possible plastic hinging region. However, the effect of such variables strongly co-related to each other.

A Study on the Structural Performance of Steel Plate Damper (강재 플레이트 댐퍼의 구조성능에 관한 연구)

  • Youn, Ilro;Kim, Cheol Hwan;Do, Cheon Gi;Jang, Woong
    • Journal of Korean Society of Steel Construction
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    • v.29 no.2
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    • pp.159-167
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    • 2017
  • The earthquake which was recently occurred in Kyeongju area caused serious damage to several structures. It is needed to improve capacity against seismic of existing structures constructed before providing seismic design code. This paper is to verify the structural characteristics proposed diagonal steel dampers for existing structures to enhance the seismic resist capacity. The experimental and analysis study were undertaken to obtain the load-displacement relationships of diagonal steel dampers. The valuables were angels and spaces of strut. As a result, it is verified that the proposed steel damper is effective in the seismic reinforcement of existing structures.

Performance assessment of multi-hazard resistance of Smart Outrigger Damper System (스마트 아웃리거 댐퍼시스템의 멀티해저드 저항성능평가)

  • Kim, Hyun-Su
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.5
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    • pp.139-145
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    • 2018
  • An outrigger system is used widely to increase the lateral stiffness of high-rise buildings, resulting in reduced dynamic responses to seismic or wind loads. Because the dynamic characteristics of earthquake or wind loads are quite different, a smart vibration control system associated with an outrigger system can be used effectively for both seismic and wind excitation. In this study, an adaptive smart structural control system based on an outrigger damper system was investigated for the response reduction of multi-hazards, including seismic and wind loads. A MR damper was employed to develop the smart outrigger damper system. Three cities in the U.S., L.A., Charleston, and Anchorage, were used to generate multi-hazard earthquake and wind loads. Parametric studies on the MR damper capacity were performed to investigate the optimal design of the smart outrigger damper system. A smart control algorithm was developed using a fuzzy controller optimized by a genetic algorithm. The analytical results showed that an adaptive smart structural control system based on an outrigger damper system can provide good control performance for multi-hazards of earthquake and wind loads.