• Title, Summary, Keyword: low-rise building

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Monitoring of wind effects on an instrumented low-rise building during severe tropical storm

  • Li, Q.S.;Hu, S.Y.
    • Wind and Structures
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    • v.20 no.3
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    • pp.469-488
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    • 2015
  • A full-scale instrumented low-rise building with gable roof was built at a coastal site with a high incidence of tropical cyclones for monitoring of wind effects on the building during windstorms. This paper presents the field measurements of the wind velocity field around and the wind-induced pressures on the low-rise building during the passage of severe tropical storm Soudelor. Near-ground wind characteristics such as wind speed, wind direction, turbulence intensity, gust factor, turbulence integral length scale and wind velocity spectra were investigated. The wind-induced pressures on the roof of the building were analyzed and discussed. The results revealed that the eave and ridge edges on the roof were subjected to the most severe suction pressures under quartering winds. These suction pressures showed obvious non-Gaussian behavior. The measured results were compared with the provisions of ASCE 7-10 to assess the suitability of the code of practice for the wind-resistant design of low-rise buildings under tropical cyclones. The field study aims to provide useful information that can enhance our understanding of the extreme wind effects on low-rise buildings in an effort to reduce tropical cyclone wind damages to residential buildings.

A comparative study on dynamic behavior of high-rise building and low-rise building considering SSI analysis (SSI 해석을 고려한 초고층 및 저층 건물 동적거동 비교 연구)

  • You, Kwang-Ho;Kim, Seung-Jin
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.20 no.6
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    • pp.973-987
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    • 2018
  • Most of the previous seismic analyses have been carried out by separating the ground and structures, and there is a lack of comparative study on the dynamic behavior of high-rise and low-rise buildings. Therefore, in this study, the sensitivity analysis was performed with selected parameters by using a finite element analysis program in order to grasp the dynamic behavior of high-rise and low-rise buildings. As a result, it was turned out that the horizontal displacement, the interstory drift ratio, and the bending stress of a high-rise building were more affected by a long seismic wave than a low-rise buildings. Also, the weak parts of a high-rise and low-rise building were more affected by type of seismic wave than the ground conditions. Therefore, it is inferred that it will be helpful for seismic designs to consider the influence of ground conditions and seismic wave type on buildings.

Structural Design of Nakanoshima Festival Tower West that Achieved High-Grade Seismic Performance

  • Kumano, Takehito;Yoshida, Satoshi;Saburi, Kazuhiro
    • International Journal of High-Rise Buildings
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    • v.6 no.3
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    • pp.217-226
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    • 2017
  • This paper summarizes the structural concept and design of the "Nakanoshima Festival Tower West" in Osaka, Japan, which is 200m high and has a super-high damping system. Its superstructure is mainly composed of a central core and outer tube frames. It has a bottom truss structure at the boundary between the low-rise and mid-rise sections of the building, where the column arrangement is changed. Besides, the high-rise section of the building has a neck truss structure. These truss structures smoothly transfer the axial forces of the columns and reduce the flexural deformations induced by horizontal loads. Oil dampers with extremely high damping capacity are installed in the rigid walls named the "Big Wall Frames" of the low-rise section. Moreover, many braces and damping devices are well arranged in the center core of each story. The damping effects of these devices ensure that all structural members are remain within the elastic range and that story drifts are within 1/150 in large earthquakes. This super-high damping structure in the low-rise section is named the "Damping Layer". The whole structural system is named the "Super Damping Structure". The whole structural systems enhance the building's safety, comfort and Business Continuity Planning (BCP) under large earthquakes.

A Study on Problems of High-rise Building Fires in Korea and the Basic Directions for Fire Safety of High-rise Building Design (우리나라 고층건축화재의 문제점과 그 대책의 기본방향에 관한 연구)

  • 이강훈
    • Fire Science and Engineering
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    • v.4 no.2
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    • pp.15-26
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    • 1990
  • Building become higher. larger and more complex than ever before, showing abrupt changes in building structures. forms and mechanical systems. Likewise hazads of fire and the scale of fire losses become more and more greater. Therefore. considerations for fire safety take up great portion of the building design process. In this study, problems of high-rise building fires and basic directions for fire safety of high-rise building design were studied through the statistical analysis of 138 fire cases. The results of this study are summarized as follows : ·Most of the fires in high-rise building occur on the low floors and the fire frequencies are very low on the upper floors. Fire casualties are liable to be more on the upper floors than on tile floor of fire origin. ·The important causes of evacuation failures were analyzed as being late in escape and lack of stairwell enclosures. ·The main cause of vertical fire spread is lack of stairwell enclosures. However, the fire spreads mainly through the enterior windows in apartment houses. The combustible materials in buildings act on as the major factors of horizontal fire spread and the improper fire doors play role of another the critical causes. ·The basic directions for fire safety of high-rise building design put much stress firstly on the compartmentation of the buildings effectively performing the provision of safe escape routes and the safe refuse places in buildings.

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Refined damage prediction of low-rise building envelope under high wind load

  • Pan, F.;Cai, C.S.;Zhang, W.;Kong, B.
    • Wind and Structures
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    • v.18 no.6
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    • pp.669-691
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    • 2014
  • Since low-rise residential buildings are the most common and vulnerable structures in coastal areas, a reliable prediction of their performance under hurricanes is necessary. The present study focuses on developing a refined finite element model that is able to more rigorously represent the load distributions or redistributions when the building behaves as a unit or any portion is overloaded. A typical 5:12 sloped low-rise residential building is chosen as the prototype and analyzed under wind pressures measured in the wind tunnel. The structural connections, including the frame-to-frame connections and sheathing-to-frame connections, are modeled extensively to represent the critical structural details that secure the load paths for the entire building system as well as the boundary conditions provided to the building envelope. The nail withdrawal, the excessive displacement of sheathing, the nail head pull-through, the sheathing in-plane shear, and the nail load-slip are found to be responsible for the building envelope damage. The uses of the nail type with a high withdrawal capacity, a thicker sheathing panel, and an optimized nail edge distance are observed to efficiently enhance the building envelope performance based on the present numerical damage predictions.

Variation in wind load and flow of a low-rise building during progressive damage scenario

  • Elshaer, Ahmed;Bitsuamlak, Girma;Abdallah, Hadil
    • Wind and Structures
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    • v.28 no.6
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    • pp.389-404
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    • 2019
  • In coastal regions, it is common to witness significant damages on low-rise buildings caused by hurricanes and other extreme wind events. These damages start at high pressure zones or weak building components, and then cascade to other building parts. The state-of-the-art in experimental and numerical aerodynamic load evaluation is to assume buildings with intact envelopes where wind acts only on the external walls and correct for internal pressure through separate aerodynamic studies. This approach fails to explain the effect of openings on (i) the external pressure, (ii) internal partition walls; and (iii) the load sharing between internal and external walls. During extreme events, non-structural components (e.g., windows, doors or rooftiles) could fail allowing the wind flow to enter the building, which can subject the internal walls to lateral loads that potentially can exceed their load capacities. Internal walls are typically designed for lower capacities compared to external walls. In the present work, an anticipated damage development scenario is modelled for a four-story building with a stepped gable roof. LES is used to examine the change in the internal and external wind flows for different level of assumed damages (starting from an intact building up to a case with failure in most windows and doors are observed). This study demonstrates that damages in non-structural components can increase the wind risk on the structural elements due to changes in the loading patterns. It also highlights the load sharing mechanisms in low rise buildings.

Particle Image Velocimetry Measurement of Unsteady Turbulent Flow around Regularly Arranged High-Rise Building Models

  • Sato, T.;Hagishima, A.;Ikegaya, N.;Tanimoto, J.
    • International Journal of High-Rise Buildings
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    • v.2 no.2
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    • pp.105-113
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    • 2013
  • Recent studies proved turbulent flow properties in high-rise building models differ from those in low-rise building models by comparing turbulent statistics. Although it is important to understand the flow characteristics within and above high-rise building models in the study of urban environment, it is still unknown and under investigation. For this reason, we performed wind tunnel experiment using Particle Image Velocimetry (PIV) to investigate and identify the turbulent flow properties and characteristic flow patterns in high-rise building models. In particular, we focus on instantaneous flow field near the canopy and extracted flow field when homogeneous flow field were observed. As a result, six characteristic flow patterns were identified and the relationship between these flow patterns and turbulent organized structure were shown.

Structural Design of Mid-Story Isolated High-Rise Building - Roppongi Grand Tower

  • Nakamizo, Daiki;Koitabashi, Yuichi
    • International Journal of High-Rise Buildings
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    • v.7 no.3
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    • pp.233-242
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    • 2018
  • Since the response reduction effect on over 200-meter-tall resulting from the seismic isolation system is smaller in general than low-rise and mid-rise buildings, mid-story isolated buildings are considered to reduce the response in the upper part above the isolation story, however, in many cases, the acceleration response just below the isolation story is likely to be the largest. This paper presents the structural design schemes, the design of the main structural frames, and the constructions of a 230-meter-tall super high-rise building with mid-story isolation mechanism integrated in Roppongi, Tokyo. Moreover, this paper shows how the architectural and structural design for integrating a mid-story isolation system in a super high-rise building has been conducted and what solutions have been derived in this project. The realization of this building indicates new possibilities for mid-story isolation design for super high-rise buildings.

Short term unsteady wind loading on a low-rise building

  • Sterling, M.;Baker, C.J.;Hoxey, R.P.
    • Wind and Structures
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    • v.6 no.5
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    • pp.403-418
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    • 2003
  • This paper presents an extensive analysis of the short term, unsteady wind loading on a low-rise building. The building is located in a rural environment and only the specific situation of wind flow orthogonal to the long face of the structure is considered. The data is analysed using conventional analysis and less traditional methods such as conditional sampling and wavelet analysis. The nature of the flow field over the building is found to be highly unsteady and complex. Fluctuating pressures on the windward wall are shown to a large extent to be caused by the fluctuations in the upstream flow, whereas extreme pressures on the roof are as a result of high intensity small scale flow structures. On the roof of the building a significant amount of energy is shown to exist at frequencies above 1 Hz.

Seismic Damage to RC Low-rise Building Structures Having Irregularities at the Ground Story During the 15 November 2017 Pohang, Korea, Earthquake (2017.11.15. 포항 흥해지진의 저층 RC 비틀림 비정형 건축물의 피해 및 손상 특성)

  • Hwang, Kyung Ran;Lee, Han Seon
    • Journal of the Earthquake Engineering Society of Korea
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    • v.22 no.3
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    • pp.103-111
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    • 2018
  • This study examines the seismic failure of RC low-rise building structures having irregularities at the ground story during the 15 November 2017 Pohang, Korea, earthquake, $M_w=5.4$, which is the second strongest since the government began monitoring them in 1978 in South Korea. Some 2,000 private houses were damaged or destroyed in this earthquake. Particularly, serious damage to the piloti story of RC low-rise residential building structures of fewer than five stories was observed within 3 km of the epicenter with brittle shear failure of columns and walls due to severe torsional behavior. Buildings below six stories constructed before 2005 did not have to comply with seismic design requirements, so confinement detailing of columns and walls also led to inadequate performance. However, some buildings constructed after 2005 were damaged at the flexible side of the piloti story due to the high torsional irregularity. Based on these results, this study focuses on the problems of the seismic torsion design approach in current building codes.