• Title/Summary/Keyword: low-rise buildings

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Seismic Performance Evaluation of Medium-and Low-rise R/C Buildings Strengthened with RCSF External Connection Method by Pseudo Dynamic Test (유사동적실험에 의한 RCSF 외부접합공법으로 내진보강 된 중·저층 철근콘크리트 건물의 내진성능 평가)

  • Lee, Kang-Seok
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.19 no.1
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    • pp.13-22
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    • 2015
  • In this study, a new RCSF (Reinforced Concrete Steel Frame) external connection method is proposed for seismic strengthening of medium-and low-rise reinforced concrete buildings. The RCSF method, proposed in this study, is capable of carrying out the seismic retrofitting construction while residents can live inside structures. The method is one of the strength design approach by retrofit which can easily increase the ultimate lateral load capacity of concrete buildings controlled by shear. The pseudo-dynamic test, designed using a existing school building in Korea, was carried out in order to verify the seismic strengthening effects of the proposed method in terms of the maximum load carrying capacity and ductility. Test results revealed that the proposed RCSF strengthening method installed in RC frame enhanced conspicuously the strength and displacement capacities, and the method can resist markedly under the large scaled earthquake intensity level.

A New Methodology for Seismic Capacity Evaluation of Low-rise R/C Buildings (비선형요구내력스펙트럼을 이용한 저층 R/C 건물의 내진성능 평가법)

  • Lee, Kang Seok
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.15 no.3
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    • pp.106-115
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    • 2011
  • This study proposed a new methodology for seismic capacity evaluation of low-rise reinforced concrete (RC) buildings based on non-linear required spectrum. In order to verify the reliability of the proposed method, relationships between results obtained using the proposed method and the non-linear dynamic analyses were investigated. Compared with the seismic protection index (Es=0.6) defined in the Japanese Standard, the applicability of the method was also estimated. Research results indicate that the method proposed in this study compares reasonably well with the detailed evaluation methods. Using the seismic evaluation method developed in this study, the seismic capacity category and earthquake damage degree of low-rise RC buildings corresponding to a specific earthquake level can be effectively estimated.

Seismic Performance Evaluation of Seismic Strengthening Method using SRCF External Connection of Medium and Low-rise R/C Buildings (중·저층 철근콘크리트 건물의 SRCF 외부접합 내진보강공법의 내진성능 평가)

  • Lee, Kang-Seok;Jung, Jue-Seong;Lee, Jong-Kweon
    • Journal of the Korea Concrete Institute
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    • v.27 no.2
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    • pp.147-155
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    • 2015
  • A new SRCF (Steel Reinforced Concrete Frame) external connection method for seismic strengthening of medium-and low-rise reinforced concrete buildings is reported in this paper. The SRCF method, proposed in this study, is capable of carrying out the seismic retrofitting construction while residents can live inside building. The method is one of the strength design approach by retrofit which can easily increase the ultimate lateral load capacity of concrete buildings controlled by shear. The pseudo-dynamic test, designed using a existing school building in Korea, was carried out in order to verify the seismic strengthening effects of the proposed method in terms of the maximum load carrying capacity and deformation. Test results revealed that the proposed SRCF strengthening method installed in RC frame enhanced conspicuously the strength and deformation capacities, and the method can resist markedly under the large scaled earthquake intensity level.

Application of Hybrid Seismic Isolation System to Realize High Seismic Performance for Low-rise Lightweight Buildings (저층 경량건물의 고성능 내진을 위한 복합면진시스템의 적용)

  • Chun, Young-Soo
    • Land and Housing Review
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    • v.4 no.2
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    • pp.185-192
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    • 2013
  • This study presents application effects of hybrid seismic isolation system to realize high seismic performance for low-rise lightweight buildings through a non-linear analysis and onsite experiments. The complex seismic isolation system applied in this study is a method of mixing sliding bearing and laminated rubber bearing in order to overcome limitation of laminated rubber bearing in increasing natural period of the whole seismic isolation system. As a result of the non-linear analysis, seismic isolation buildings designed with complex seismic isolation system are safe because its maximum response displacement is within allowable design displacement even for a strong earthquake which rarely occurs and its maximum response shear is less than design seismic force. As a result of the onsite experiment, the rigidity of seismic isolation stories corresponds to approximately 95.8% of the design equivalent stiffness value. This indicates that actual properties of the whole seismic isolation system correspond to design values.

A Comparative Analysis of Terrorism Threat Level of Domestic Tall Buildings and General Buildings through Rapid Visual Screening (Rapid Visual Screening통한 건물 높이별 테러위험도 비교 분석)

  • Song, Jin-Young;Yoon, Sung-Won
    • Journal of Korean Association for Spatial Structures
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    • v.11 no.4
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    • pp.89-99
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    • 2011
  • As the scope of the target of terrorism is recently extending, the danger of domestic terroristic attacks is increasing constantly, and the form of terrorism is changing from hard targets such as significant facilities of the country into soft target of multi-complex buildings such as skyscrapers. Accordingly this study analyzes the terrorism threat level on skyscrapers by comparing the assessment results of the terrorism threat level on skyscrapers and high-rise buildings with the assessment results of the terrorism threat level on low-rise buildings through fema 455 - Rapid Visual Screening. As a result, skyscrapers and high-rise buildings are relatively higher threat rating than consequences and vulnerability rating. This is caused by the fact that the terrorism threat level on skyscrapers is high due to their residents and their national or regional symbolism and visibility

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.

Serviceability evaluation methods for high-rise structures considering wind direction

  • Ryu, Hye-Jin;Shin, Dong-Hyeon;Ha, Young-Cheol
    • Wind and Structures
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    • v.30 no.3
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    • pp.275-288
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    • 2020
  • High-rise buildings are very slender and flexible. Their low stiffness values make them vulnerable to horizontal loads, such as those associated with wind or earthquakes. For high-rise buildings, the threat to serviceability caused by wind-induced vibration is an important problem. To estimate the serviceability under wind action, the response acceleration of a building at the roof height is used. The response acceleration is estimated by the same wind speed at all wind directions. In general, the effect of wind direction is not considered. Therefore, the response accelerations obtained are conservative. If buildings have typical plans and strong winds blow from relatively constant wind directions, it is necessary to account for the wind direction to estimate the response accelerations. This paper presents three methods of evaluating the response accelerations while considering the effects of wind direction. These three serviceability evaluation methods were estimated by combining the wind directional frequency data obtained from a weather station with the results of a response analysis using wind tunnel tests. Finally, the decrease in the efficiencies of the response acceleration for each serviceability evaluation method was investigated by comparing the response acceleration for the three methods accounting for wind direction with the response acceleration in which wind direction was not considered.

Effects of turbulence intensity and exterior geometry on across-wind aerodynamic damping of rectangular super-tall buildings

  • Quan, Y.;Cao, H.L.;Gu, M.
    • Wind and Structures
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    • v.22 no.2
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    • pp.185-209
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    • 2016
  • Across-wind aerodynamic damping ratios are identified from the wind-induced acceleration responses of 15 aeroelastic models of rectangular super-high-rise buildings in various simulated wind conditions by using the random decrement technique. The influences of amplitude-dependent structural damping ratio and natural frequency on the estimation of the aerodynamic damping ratio are discussed and the identifying method for aerodynamic damping is improved at first. Based on these works, effects of turbulence intensity $I_u$, aspect ratio H/B, and side ratio B/D on the across-wind aerodynamic damping ratio are investigated. The results indicate that turbulence intensity and side ratio are the most important factors that affect across-wind aerodynamic damping ratio, whereas aspect ratio indirectly affects the aerodynamic damping ratio by changing the response amplitude. Furthermore, empirical aerodynamic damping functions are proposed to estimate aerodynamic damping ratios at low and high reduced speeds for rectangular super-high-rise buildings with an aspect ratio in the range of 5 to 10, a side ratio of 1/3 to 3, and turbulence intensity varying from 1.7% to 25%.

Full-scale tests and analytical model of the Teflon-based lead rubber isolation bearings

  • Wang, Lu;Oua, Jin;Liu, Weiqing;Wang, Shuguang
    • Structural Engineering and Mechanics
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    • v.48 no.6
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    • pp.809-822
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    • 2013
  • Base isolation is widely used in seismic resisting buildings due to its low construction cost, high reliability, mature theory and convenient usage. However, it is difficult to design the isolation layer in high-rise buildings using the available bearings because high-rise buildings are characterized with long period, low horizontal stiffness, and complex re-distribution of the internal forces under earthquake loads etc. In this paper, a simple and innovative isolation bearing, named Teflon-based lead rubber isolation bearing, is developed to address the mentioned problems. The Teflon-based lead rubber isolation bearing consists of friction material and lead rubber isolation bearing. Hence, it integrates advantages of friction bearings and lead rubber isolation bearings so that improves the stability of base isolation system. An experimental study was conducted to validate the effectiveness of this new bearing. The effects of vertical loading, displacement amplitude and loading frequency on the force-displacement relationship and energy dissipation capacity of the Teflon-based lead rubber isolation bearing were studied. An analytical model was also proposed to predict the force-displacement relationship of the new bearing. Comparison of analytical and experimental results showed that the analytical model can accurately predict the force-displacement relationship and elastic shear deflection of the Teflon-based lead rubber isolation bearings.

A Study on the Development of Building Envelope Elements for Energy Reduction in Multi- Rise Residential Buildings

  • Lee, Myung Sik
    • Architectural research
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    • v.18 no.4
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    • pp.151-155
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    • 2016
  • It is necessary to improve the performance of buildings with respect to the energy efficiency while improving the quality of occupants' lives through a sustainable built environment. During the design and development process, building projects must have a comprehensive, integrated perspective that seeks to reduce heating, cooling and lighting loads through climate-responsive designs. The aim of this study is to find an optimal thermal transmittance (U-values) for building envelope elements for low energy multi-rise residential buildings in the early design phase in Korea. The study found that using small U-values of $0.15w/m^2K$ for exterior walls, ceilings and floors and $1.0w/m^2K$ for south and north facing windows has resulted in energy reduction of 22.1%-59.4% in the south facing rooms and 43%-77.6% of the north facing rooms. It has also found the energy load reduction potential of using small U-values are higher on the north facing rooms. The findings of this study can be suggested to be used as a baseline case for low energy consumption studies. It can also be used to determine appropriate envelope materials and insulation values.