• Title/Summary/Keyword: post and beam

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Air Tightness Performance of Residential Timber Frame Buildings

  • Kim, Hyun-Bae;Park, Joo-Saeng;Hong, Jung-Pyo;Oh, Jung-Kwon;Lee, Jun-Jae
    • Journal of the Korean Wood Science and Technology
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    • v.42 no.2
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    • pp.89-100
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    • 2014
  • Energy consumption statistics in 2005 from the Korea Energy Management Corporation show that building energy usage was about 24.2% of total domestic energy consumption, and 64% of total building energy usage was consumed by residential buildings. Thus, about 10% of total domestic energy consumption is due to the heating of residential buildings. Building energy can be calculated by the configuration of the building envelope and the rate of infiltration (the volume of the infiltration of outdoor air and the leakage of indoor air), and by doing so, the annual energy usage for heating and cooling. Therefore, air-tightness is an important factor in building energy conservation. This investigate air infiltration and various factors that decrease it in timber frame buildings and suggest ways to improve air-tightness for several structural types. Timber frame buildings can be classified into light frame, post and beam, and log house. Post and beam includes Han-ok (a Korean traditional building). Six light frame buildings, three post and beam buildings, one Korean traditional Han-ok and a log house were selected as specimens. Blower door tests were performed following ASTM E779-03. The light frame buildings showed the highest air-tightness, followed by post and beam structures, and last, log houses.

A study on the Plan Modular Establishment for the Development of Wooden Dwelling Model - Focused on the Post & Beam Structure - (목조주택 모형개발을 위한 평면모듈 설정에 대한 연구 - 기둥-보 방식 구조를 중심으로 -)

  • Kang, Man-Ho;Joo, Seok-Joong;Kim, Jae-Deok
    • Journal of the Korean housing association
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    • v.18 no.1
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    • pp.141-148
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    • 2007
  • In this research, to develope wooden house model with post & beam structure which is commensurate with domestic environment, we analyzed the size and module of a unit space and space organization of existing habitation, then, based on the result, we tried to suggest general wood house modules. For this, we investigated 98 floor plans for 30 pyeong apartment in Seoul, Gyounggi-do, Gwangju, and Jeolla-do. The results are showed as follows. 1) It has shown that 7 posts distances are available in 2 bay floor plan type - 3.0 m, 3.3 m, 3.6 m, 3.9 m, 4.2 m, 4.5 m, and 4.8 m. 2) It has shown that 8 posts distances are available in 3 bay floor plan type - 3.0 m, 3.3 m, 3.6 m, 3.9 m, 4.2 m, 4.5 m, 4.8 m, and 5.1 m. It was concluded as follows, applying the standard of regulations of horizontal modular coordination design, from $\ulcorner$the standard of modular coordination design in architecture(KSF 1525)$\lrcorner$. 1) The available widths are 3.0 m, 3.3 m, 3.6 m, 4.2 m, and 4.8 m, and the available depths are 3.0 m, 3.3 m, 3.6 m, and 4.2 m. 2) To guarantee a space through post module of a room combination, we can use a module of 3.6 m, 4.2 m, 4.8 m except 3.0 m, 3.3 m among available modules. The module investigated in post & beam structure wooden house is applied in basic 6 floor plans as follows. 1) When organize the room on the basis of tile module of 3.6 m, 4.2 m, it was possible to organize the floor plan. 2) After arranging main room, making practical application of variableness which is advantage of post & beam structure, putting to practical use of extra space that becomes the combination of atypical room such as kitchen, dining room, and bathroom, it was possible to organize the floor plan of the residence. 3) It is possible to organize whole rooms through the plan module from 3.6 m to 4.2 m, that decides the floor plan of a wooden house.

Hybrid model-based and deep learning-based metal artifact reduction method in dental cone-beam computed tomography

  • Jin Hur;Yeong-Gil Shin;Ho Lee
    • Nuclear Engineering and Technology
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    • v.55 no.8
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    • pp.2854-2863
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    • 2023
  • Objective: To present a hybrid approach that incorporates a constrained beam-hardening estimator (CBHE) and deep learning (DL)-based post-refinement for metal artifact reduction in dental cone-beam computed tomography (CBCT). Methods: Constrained beam-hardening estimator (CBHE) is derived from a polychromatic X-ray attenuation model with respect to X-ray transmission length, which calculates associated parameters numerically. Deep-learning-based post-refinement with an artifact disentanglement network (ADN) is performed to mitigate the remaining dark shading regions around a metal. Artifact disentanglement network (ADN) supports an unsupervised learning approach, in which no paired CBCT images are required. The network consists of an encoder that separates artifacts and content and a decoder for the content. Additionally, ADN with data normalization replaces metal regions with values from bone or soft tissue regions. Finally, the metal regions obtained from the CBHE are blended into reconstructed images. The proposed approach is systematically assessed using a dental phantom with two types of metal objects for qualitative and quantitative comparisons. Results: The proposed hybrid scheme provides improved image quality in areas surrounding the metal while preserving native structures. Conclusion: This study may significantly improve the detection of areas of interest in many dentomaxillofacial applications.

Novel steel bracket and haunch hybrid system for post-earthquake retrofit of damaged exterior beam-column sub-assemblages

  • Kanchanadevi, A.;Ramanjaneyulu, K.
    • Structural Engineering and Mechanics
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    • v.73 no.3
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    • pp.239-257
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    • 2020
  • In the present study, an innovative steel bracket and haunch hybrid scheme is devised, for retrofitting of earthquake damaged deficient beam-column sub-assemblages. Formulations are presented for evaluating haunch force factor under combined load case of lateral and gravity loads for the design of double haunch retrofit. The strength hierarchies of control and retrofitted beam-column sub-assemblages are established to showcase the efficacy of the retrofit in reversing the undesirable strength hierarchy. Further, the efficacy of the proposed retrofit scheme is demonstrated through experimental investigations carried out on gravity load designed (GLD), non-ductile and ductile detailed beam-column sub-assemblages which were damaged under reverse cyclic loading. The maximum load carried by repaired and retrofitted GLD specimen in positive and negative cycle is 12% and 28% respectively higher than that of the control GLD specimen. Further, the retrofitted GLD specimen sustained load up to drift ratio of 5.88% compared with 2.94% drift sustained by control GLD specimen. Repaired and retrofitted non-ductile specimen, could attain the displacement ductility of three during positive cycle of loading and showed improved ductility well above the expected displacement ductility of three during negative cycle. The hybrid haunch retrofit restored the load carrying capacity of damaged ductile specimen to the original level of control specimen and improved the ductility closer to the expected displacement ductility of five. The total cumulative energy dissipated by repaired and retrofitted GLD, non-ductile and ductile specimens are respectively 6.5 times, 2.31 times, 1.21 times that of the corresponding undamaged control specimens. Further, the damage indices of the repaired and retrofitted specimens are found to be lower than that of the corresponding control specimens. The novel and innovative steel bracket and haunch hybrid retrofit scheme proposed in the present study demonstrated its effectiveness by attaining the required displacement ductility and load carrying capacity and would be an excellent candidate for post-earthquake retrofit of damaged existing RC structures designed according to different design evolutions.

Study on thermal buckling and post-buckling behaviors of FGM tubes resting on elastic foundations

  • She, Gui-Lin;Ren, Yi-Ru;Xiao, Wan-Shen;Liu, Haibo
    • Structural Engineering and Mechanics
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    • v.66 no.6
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    • pp.729-736
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    • 2018
  • This paper studies thermal buckling and post-buckling behaviors of functionally graded materials (FGM) tubes subjected to a uniform temperature rise and resting on elastic foundations via a refined beam model. Compared to the Timoshenko beam theory, the number of unknowns of this model are the same and no correction factors are required. The material properties of the FGM tube vary continuously in the radial direction according to a power function. Two ends of the tube are assumed to be simply supported and in-plane boundary conditions are immovable. Energy variation principle is employed to establish the governing equations. A two-step perturbation method is adopted to determine the critical thermal buckling loads and post-buckling paths of the tubes with arbitrary radial non-homogeneity. Through detailed parametric studies, it can be found that the tube has much higher buckling temperature and post-buckling strength when it is supported by an elastic foundation.

Optimal Active Control of Bridges using Modified King-post Mechanism (수정된 King-post mechanism을 이용한 교량 구조물의 최적능동제어)

  • 김준형;정길호;이인원
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1995.10a
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    • pp.103-110
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    • 1995
  • This Paper develops a new control system to reduce the vibration of bridges using King-post mechanism. The optimal active control theory is used in the control system. The positions of post and roller in the King-post mechanism are important factors, since the vibration of bridges is very sensitive to their variations. To demonstrate the efficiency of the proposed control mechanism, a simply supported beam under moving load is considered.

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Analytical approximate solutions for large post-buckling response of a hygrothermal beam

  • Yu, Yongping;Sun, Youhong
    • Structural Engineering and Mechanics
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    • v.43 no.2
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    • pp.211-223
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    • 2012
  • This paper deals with large deformation post-buckling of a linear-elastic and hygrothermal beam with axially nonmovable pinned-pinned ends and subjected to a significant increase in swelling by an alternative method. Analytical approximate solutions for the geometrically nonlinear problem are presented. The solution for the limiting case of a string is also obtained. By coupling of the well-known Maclaurin series expansion and orthogonal Chebyshev polynomials, the governing differential equation with sinusoidal nonlinearity can be reduced to form a cubic-nonlinear equation, and supplementary condition with cosinoidal nonlinearity can also be simplified to be a polynomial integral equation. Analytical approximations to the resulting boundary condition problem are established by combining the Newton's method with the method of harmonic balance. Two approximate formulae for load along axis, potential strain for free hygrothermal expansion and periodic solution are established for small as well as large angle of rotation at the end of the beam. Illustrative examples are selected and compared to "reference" solution obtained by the shooting method to substantiate the accuracy and correctness of the approximate analytical approach.

Flexural tests on two-span unbonded post-tensioned lightweight concrete beams

  • Yang, Keun-Hyeok;Lee, Kyung-Ho;Yoon, Hyun-Sub
    • Structural Engineering and Mechanics
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    • v.72 no.5
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    • pp.631-642
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    • 2019
  • The objective of the present study is to examine the flexural behavior of two-span post-tensioned lightweight aggregate concrete (LWAC) beams using unbonded tendons and the reliability of the design provisions of ACI 318-14 for such beams. The parameters investigated were the effective prestress and loading type, including the symmetrical top one-point, two third-point, and analogous uniform loading systems. The unbonded prestressing three-wire strands were arranged with a harped profile of variable eccentricity. The total length of the beam, measured between both strand anchorages, was 11000 mm. The test results were compared with those compiled from simply supported LWAC one-way members, wherever possible. The ultimate load capacity of the present beam specimens was evaluated by the collapse mechanism of the plasticity theorem and the nominal section moment strength calculated following the provision of the ACI 318-14. The test results showed that the two-span post-tensioned LWAC beams had lower stress increase (Δfps) in the unbonded tendons than the simply supported LWAC beams with a similar reinforcement index. The effect of the loading type on Δfps and displacement ductility was less significant for two-span beams than for the comparable simply supported beams. The design equations for Δfps and Δfps proposed by ACI 318-14 and Harajli are conservative for the present two-span post-tensioned LWAC beams, although the safety decreases for the two-span beam, compared to the ratios between experiments and predictions obtained from simply supported beams.

Paresthesia diagnosed using cone-beam computed tomography: a case report

  • Kumar, Umesh;Kaur, Charan Kamal;Vashisht, Ruchi;Rattan, Vidya
    • Journal of Dental Anesthesia and Pain Medicine
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    • v.20 no.2
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    • pp.95-99
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    • 2020
  • Various dental procedures, such as injection administration, surgical treatment, and endodontic treatment, can cause injury to the nerves. The most commonly injured nerves are the inferior alveolar and lingual nerves. This can manifest as altered sensation to the area of innervation of the injured nerve, such as the lower lip, chin, teeth, tongue, and mucosa. Altered sensations or loss of sensation are relatively infrequent complications in daily dental practice. Here, we report an uncommon case of altered sensation in the midfacial region caused by an endodontic procedure and discuss the need to consider local dental causes in the differential diagnosis of numbness in the facial region.

Numerical study on fire resistance of cyclically-damaged steel-concrete composite beam-to-column joints

  • Ye, Zhongnan;Heidarpour, Amin;Jiang, Shouchao;Li, Yingchao;Li, Guoqiang
    • Steel and Composite Structures
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    • v.43 no.5
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    • pp.673-688
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    • 2022
  • Post-earthquake fire is a major threat since most structures are designed allowing some damage during strong earthquakes, which will expose a more vulnerable structure to post-earthquake fire compared to an intact structure. A series of experimental research on steel-concrete composite beam-to-column joints subjected to fire after cyclic loading has been carried out and a clear reduction of fire resistance due to the partial damage caused by cyclic loading was observed. In this paper, by using ABAQUS a robust finite element model is developed for exploring the performance of steel-concrete composite joints in post-earthquake fire scenarios. After validation of these models with the previously conducted experimental results, a comprehensive numerical analysis is performed, allowing influential parameters affecting the post-earthquake fire behavior of the steel-concrete composite joints to be identified. Specifically, the level of pre-damage induced by cyclic loading is regraded to deteriorate mechanical and thermal properties of concrete, material properties of steel, and thickness of the fire protection layer. It is found that the ultimate temperature of the joint is affected by the load ratio while fire-resistant duration is relevant to the heating rate, both of which change due to the damage induced by the cyclic loading.