In this study, the characteristics of wind pressure distribution on circular retractable dome roofs with a low rise-to-span ratio were analyzed under various approaching flow conditions by obtaining and analyzing wind pressures under three different turbulent boundary layers. Compared to the results of previous studies with a rise-to-span ratio of 0.1, it was confirmed that a lower rise-to-span ratio increases the reattachment length of the separated approaching flow, thereby increasing the influence of negative pressure. Additionally, it was found that wind pressures varied significantly according to the characteristics of the turbulence intensity. Based on these experimental results, a model for peak net pressure coefficients for cladding design was proposed, considering variations in turbulence intensity and height.
Recently, the number of cases of fire spreading due to exterior materials of buildings is increasing. Due to the nature of modern architecture, which emphasizes the aesthetics of buildings, because buildings pursue a splendid appearance, they are inexpensive and have relatively good insulation performance, but an increasing number of buildings are adopting insulation materials that have poor fire safety performance. The risk of spread is also greatly increased. Since the exterior wall of a building is made of a variety of materials and structures, it is composed of a combination of several elements, including materials such as insulation and finishing materials. Therefore, it was determined that it was necessary to introduce a more systematic evaluation method for building exterior materials, and to improve the system reflecting this, away from the existing evaluation method that only checked the fire safety performance of finishing materials.
This study investigates the wind pressure characteristics of elliptical plan retractable dome roof. Wind tunnel experiments were performed on spherical dome roofs with varying wall height-span ratios (0.1~0.5) and opening ratios (0%, 10%, 30% and 50%), similar to previous studies of cirular dome roofs. In previous study, wind pressure coefficients for open dome roofs have been proposed since there are no wind load criteria for open roofs. However, in the case of Eeliptical plan retractable dome roof, the wind pressure coefficient may be largely different due to the presence of the longitudinal direction and transverse direction. The analysis results leads to the exceeding of maximum and minimum wind pressure coefficients KBC2016 code.
본 연구에서는 한국에 대한 기후변화로 인한 미래 풍속의 변화를 예측하고, 건축물 외장재에 대한 풍해 위험도를 정량적으로 평가하였다. 미래의 기후변화로 인한 풍속의 변화를 예측하기 위해서 기상청에서 제공하는 RCP 시나리오와 HadGem3-RA 모델을 사용한 풍속 변화 예측치에 관한 이전 연구의 결과가 활용되었다. 강풍에 대한 위험도는 임의의 풍속에 대한 손상확률인 강풍 취약도 모델과 강풍이 발생할 확률인 강풍 위험 모형의 결과를 합성곱하여 평가 되었다. 강풍 취약도 모델은 몬테카를로 모사(Monte-Carlo simulation)를 사용하여 개발되었으며, 강풍 위험모델은 과거 태풍에 대한 자료와 몬테카를로 모사를 사용한 강풍의 발생확률 분석에 관한 이전 연구의 결과를 기초로 개발되었다. 본 연구에서는 강풍 위험도 연구의 결과를 기초로 미래 풍속의 변화로 인한 건축물의 강풍 위험도 변화를 정량적으로 분석하였다. 연구결과로부터 서울보다 남쪽 지역인 부산에 미래 강풍이 더 발생하는 것으로 파악되었다. 또한, RCP 4.5와 RCP 8.5 시나리오 하에서 부산에서의 미래 풍속의 차이가 크지 않기 때문에 강풍 위험도의 변화 역시 크지 않은 것으로 평가되었다. 본 연구에서 제안한 방법론은 미래 강풍으로 인한 피해를 예측하고 대비하기 위한 방법으로 사 용될 수 있을 것으로 판단된다. 본 연구에서의 강풍 위험도 평가를 국가 차원에 적용하기 위해서는 강풍 위험에 대한 공간적 확장과 더불어 피해 대상물에 대한 강풍 취약도의 추가적인 개발이 필요할 것으로 판단된다.
In this study, the whole process of 6xxx series aluminum extruded alloy for high speed train interior and exterior parts are characterized. The mechanical properties, and chemical composition of the case materials were evaluated for the 6063, 6061 and 6N01 alloy profiles and compared to the commercial materials and the evaluation results satisfied the standard. The cast product was extruded using the air slip(AS) casting method and the direct casting(DC) method and these were again heat-treated conditions with T5 or T6. The remarkable point is that the extrusion temperature and pressure of 6061 alloy were somewhat higher than those of other alloys. The reason is that 6061 alloy exhibited brittle fracture due to grain boundary segregation even at the tensile fracture surface and the fact that the product used a billet by the direct casting method instead of air slip one. The mechanical properties were evaluated for the 6063, 6061, 6N01 extruded alloys and the evaluation results were analyzed and satisfied the standard properties.
The biggest impact on the cladding design of buildings is wind loads. Wind tunnel tests were conducted to examine the applicability of current wind load standards about membrane retractable roof spatial structure. A dome model with a circular shape that is retractable to the center of the dome was made (Opening ratio = 0, 10, 30, 50). In addition, height adjustable turntables were made and tested with five patterns with H/D = 0.1, 0.2, 0.3, 0.4 and 0.5. The maximum wind pressure coefficient and the minimum wind pressure coefficient for the cladding were analyzed and the experimental wind pressure coefficient were compared with the current wind load standards, KBC2016 and AIJ-RLB(2015). The experimental value and the reference value of the enclosed roof were very similar and showed possibility of application, but opened roof case was found that the reference value was underestimated.
In this study, the extrusion process of 6xxx series aluminum cast alloy for high speed train interior or exterior parts are developed. For casting, selection of optimum alloying elements, dissolution technology, de-gassing process, production of molds conforming to the conditions of use, development of casting process control technology for various shapes and materials are performed for the development of high-quality, high strength aluminum alloys. The development of more high farmable extruded aluminum casting alloys for interior or exterior materials has been the scope of this study. The extruded die design was performed for the 6063, 6061 and 6N01 alloy profiles and extrusion test was executed. From these results, the extrusion conditions such as extrusion pressure following as billet temperature and materials were carefully examined.
In this study, the whole process of 6xxx series aluminum cast alloy for high speed train interior or exterior parts are characterized. For casting, selection of optimum alloying elements, dissolution technology, de-gassing process, production of molds conforming to the conditions of use, development of casting process control technology for various shapes and materials are performed for the development of high-quality, high strength aluminum alloys. The development of more reliable lightweight aluminum and aluminum alloy for interior or exterior materials has been the scope of this study. The mechanical properties, and chemical composition of the case materials were evaluated for the 6063, 6061 and 6N01 alloy profiles and compared to the commercial materials and the evaluation results satisfied the standard.
As demands for freeform structure were gradually increased, researches about various shapes of claddings have been conducted. Particularly, claddings made from concrete easily made complex shapes. Because of this advantage, many researches about manufacturing methods and light weight of concrete mainly have been conducted. For example ALC (Autoclaved Lightweight Concrete) was the most popular claddings that had a great strength without aggregate and were cured at high temperature and pressure conditions. This paper showed multi-layer reinforcement system, exactly 5 layers polymer reinforcement method, that consisted of 3D printing material with low weight and high performance mechanical properties. Finite element analysis were performed to predict the maximum deformations loaded by wind and self-weight. Joints of analysis model were simplified as the pin joint. The variable of this analysis was the material arrangement of 3 layers located at center among exterior layer. Finally, the maximum deformations of analysis results were compared with the limitations of claddings.
For the purpose of finding out the acoustical characteristics of exterior materials in bridge, analytical studies are performed with boundary elements method by using the commercial program SYSNOISE. Before analysis, to figure out material property, it was conducted experiments of absorption coefficient for absorptive material. And prediction of pressure were conducted I GIRDER type (before & after installation of absorption panel ) and BOX GIRDER type (before & after installation of absorption panel) The results show that when the absorption panel is installed, environment around bridge can help reduce traffic noise. It was proved to be the effective noise reduction counter-plan for a traffic noise in the bridges.
In this study, FDS fire simulation experiments and measured wind speed by applying the exterior installation portion for blocking the spread of the fire was investigated. As a result, aluminum composite panels installed in the lower and the upper part of the panel to remove all the lower side, and then the maximum wind speed 0.24 m/s and the upper side 0.58 m/s were measured. In the FDS, the measured wind speed difference air currents are approximately 3.7 times in 12 seconds, the occurrence of 17 seconds early moment wind 2.2 m/s was measured from. Before and after the fire occurred in early of the air velocity about 39 seconds was 3.5 times difference. Such air currents caused by the temperature of the building but also by the building height was found. Turbulent flame of fire by expanding the vertical extent of damage become greatly important factor. Therefore, through the exterior installation portion of the block that can delay the spread of fire is expected that this should be taken.
중정형 건축물의 중정측 외장재 설계를 위한 외압계수분포 특징을 알아보기 위해 풍압실험을 실시하였다. 본 연구를 위하여 형상비와 중정의 폭을 변화시킨 4개의 모형을 제작하였으며, 풍동실험은 금오공과대학교 토출식 경계층풍동에서 실시하였다. 본 연구의 결과로부터 중정측의 외압계수는 건물외측의 외압계수보다 감소하는 것으로 나타났다.
이 연구는 풍동실험을 통하여 건축물의 외장재에 작용하는 풍압을 측정하여 피크팩터와 피크외압계수의 특성을 규명한 것이다. 각각의 풍압공에서 측정된 풍압시계열 데이터로부터 산정된 피크외압계수와 정상확률과정에서 얻은 피크팩터를 이용한 피크외압계수를 비교하였다. 풍동실험은 금오공과대학교 소재 토출식 경계층 풍동에서 실시하였다. 본 연구를 위하여 실험모형은 변장비를 1로 고정시키고 형상비를 2, 4, 6으로 변화시킨 3개의 모형을 대상으로 실험을 실시하였다.
Considering heat insulation and beautiful sight of construction, making use of exterior panels is increasing. Recently the exterior panels now are weak very much, and so in consequence of the weakness fire spreads rapidly. Compared with internal fire, external vertical fire spread rate goes rapidly and it is extensive in spread range, therefore it is dangerous very much. Accordingly, under present condition of poor standard of exterior panels, it is required to take measure to meet the appropriate situation. In this study, by making use of FDS(Fire Dynamic Simulation) program about external vertical fire of high rise building, fire behavior is searched by computer. It is important that realizing by computer fire modeling about external vertical fire must be included certainly in procedure of fire performance design in the future. In modeling program, FDS version 5 is available, and aluminium composite panel is applied in external panels. In this study, for realizing of actual fire condition, FDS is applied by details of fire scenarios considering influence of wind.
이 논문은 풍동실험 결과를 토대로 고층아파트 건축물의 풍압분포에 대한 내용을 다루고 있다. 태풍에 의해 창유리 파손을 입은 아파트 단지의 풍압모형을 제작하여 각 건축물의 상호간섭효과를 조사하였다. 풍동실험은 풍압모형을 이용하여 대형경계 층풍동에서 수행하였다. 간섭하는 주변건물의 여부에 따른 실험결과를 비교하고 검토하였다. 주변건물이 없어서 바람을 직접 맞을 때에는 105동, 106동은 주로 정압이 작용하였지만, 주변건물이 둘러싸고 있을 때의 105동, 106동은 큰 부압이 작용하는 것을 관찰할 수 있었다. 따라서 고층아파트 외장재 설계시 외장재의 안전성 확보를 위해서는 풍동실험을 수행하여 바람에 의해 야기되는 상호간섭효과를 고려하는 것이 가장 적합한 방법이라 할 수 있다.