• Title/Summary/Keyword: Topping

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Experimental Cyclic Behavior of Precast Hybrid Beam-Column Connections with Welded Components

  • Girgin, Sadik Can;Misir, Ibrahim Serkan;Kahraman, Serap
    • International Journal of Concrete Structures and Materials
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    • v.11 no.2
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    • pp.229-245
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    • 2017
  • Post-earthquake observations revealed that seismic performance of beam-column connections in precast concrete structures affect the overall response extensively. Seismic design of precast reinforced concrete structures requires improved beam-column connections to transfer reversed load effects between structural elements. In Turkey, hybrid beam-column connections with welded components have been applied extensively in precast concrete industry for decades. Beam bottom longitudinal rebars are welded to beam end plates while top longitudinal rebars are placed to designated gaps in joint panels before casting of topping concrete in this type of connections. The paper presents the major findings of an experimental test programme including one monolithic and five precast hybrid half scale specimens representing interior beam-column connections of a moment frame of high ductility level. The required welding area between beam bottom longitudinal rebars and beam-end plates were calculated based on welding coefficients considered as a test parameter. It is observed that the maximum strain developed in the beam bottom flexural reinforcement plays an important role in the overall behavior of the connections. Two additional specimens which include unbonded lengths on the longitudinal rebars to reduce that strain demands were also tested. Strength, stiffness and energy dissipation characteristics of test specimens were investigated with respect to test variables. Seismic performances of test specimens were evaluated by obtaining damage indices.

Optimal production cost evaluation model of cogeneration system for buildings including maintenanace scheduling (보수계획을 고려한 건물용 열병합 발전의 최적 운전비용 산출 모델)

  • Kim, Y.S.;Park, J.S.;Yu, J.S.;Kim, J.H.
    • Proceedings of the KIEE Conference
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    • 1995.07b
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    • pp.559-561
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    • 1995
  • The cogeneration system has a strong merit in providing thermal and electrical energy simultaneously. Nowadays, cogeneration system is widely used in the point of efficient use of the energy resources And the installation of the system is expected to be greatly increased in each year. So, we need to develop an optimal operation planning for those systems. In this paper, we are used to result what studed at the my power system of room because it is in order to solve maintenance scheduling problem. Also we added a constraints to the proposed maintenance model for optimal maintenance rate. In the case study, we construct an multi-machine generated example system which operated in topping cycle, and calculate the yearly optimal production cost, marginal maintenance cost, and maintenance scheduling of the example system respectively.

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Pseudo-dynamic test of the steel frame - Shear wall with prefabricated floor structure

  • Han, Chun;Li, Qingning;Jiang, Weishan;Yin, Junhong;Yan, Lei
    • Steel and Composite Structures
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    • v.20 no.2
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    • pp.431-445
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    • 2016
  • Seismic behavior of new composite structural system with a fabricated floor was studied. A two-bay and three-story structural model with the scale ratio of 1/4 was consequently designed. Based on the proposed model, multiple factors including energy dissipation capacity, stiffness degradation and deformation performance were analyzed through equivalent single degree of freedom pseudo-dynamic test with different earthquake levels. The results show that, structural integrity as well as the effective transmission of the horizontal force can be ensured by additional X bracing at the bottom of the rigidity of the floor without concrete topping. It is proved that the cast-in-place floor in areas with high seismic intensity can be replaced by the prefabricated floor without pouring surface layer. The results provide a reliable theoretical basis for the seismic design of the similar structural systems in engineering application.

A Study on Adjustment of Prediction Equation for Natural Frequency Using the Simplification of Section Transformation Method of Composite Deck Plate Floor Systems (합성 데크 플레이트 바닥구조의 단면환산 단순화를 통한 고유진동수 예측식의 보정에 관한 연구)

  • 임지훈;김희철;홍원기
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.11b
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    • pp.731-738
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    • 2001
  • The conventional techniques for the prediction of natural frequency are often used to estimate the floor vibration. However. the predicted frequency differs significantly from the measured one since the predicted equation is not able to proper1y treat various material type. Transformation of slab section is necessary to predict natural frequency of composite deck plate, and this effort is complicated due to the various shape of each deck plate. In this study, a new simplified methodology to transform slab section is proposed, which treats effective depth as the distance from the top of a concrete topping to neutral axis of each deck plate. Finally proposed equation with fairly reasonable result compared to the measured values is obtained. based on the modification of vibration equation from LRFD theory. This efforts enhance errors in predicting frequency up to 15%.

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Flexural Capacity of the Encased(Slim Floor) Composite Beam with Deep Deck Plate (매입형(슬림플로어) 합성보의 휨성능 평가 -춤이 깊은 데크플레이트와 비대칭 H형강 철골보-)

  • Heo, Byung Wook;Bae, Kyu Woong;Moon, Tae Sup
    • Journal of Korean Society of Steel Construction
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    • v.16 no.2 s.69
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    • pp.235-245
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    • 2004
  • The advantages of composite construction are now well understood in terms of structural economy, good performance in service, and ease of construction. However, these conventional composite construction systems have some problems in application to steel framed buildings due to their large depth. So, in this study we executed an experimental test with the "Slim Floor"system which could reduce the overall depth of composite beam. Slim Floor system is a method of steel frame multi-story building construction in which the structural depth of each floor is minimized by incorporating the steel floor beams within the depth of the concrete floor slab. Presented herein is an experimental study that focuses on the flexural behaviour of the partially connected slim floor system with asymmetric steel beams encased in composite concrete slabs. Eight full-scale specimens were constructed and tested in this study with different steel beam height, slab width, with or without shear connection and concrete topping thickness. Observations from experiments indicated that the degree of shear connection without additional shear connection was $0.53{\sim}0.95$ times that of the full shear connection due to inherent mechnical and chemical bond stress.

Development and Quality Properties of Cereal Bars (씨리얼바 제조 및 품질특성)

  • Han Sang-Ha;Kum Jun-Seok;Lee Hyun-Yu;Park Jong-Dae
    • Food Science and Preservation
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    • v.12 no.3
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    • pp.235-240
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    • 2005
  • The purpose of this study was to develop new functional cereal bars for breakfast with 9 types of cereal(corn, whole wheat, rice, brown rice, black rice, indian millet, sprouting brown rice, black soybean, job's tear) and their chemical and sensory properties were evaluated. Process of cereal bars are cereal mixing ${\to}$ formation ${\to}$ baking ${\to}$ cooling ${\to}$ topping. Moisture content of sunsik-type cereal bars were $9.4\%$, and puffed-type cereal bars were $10.1\%$. L-values of sunsik cereal bars were lower than that of puffed type cereal bars, and a-value was the highest in sunsik-type cereal bars with fructooligosaccaride. Texture measurement showed that hardness of sunsik-type cereal bars was higher than that of puffed-type cereal bars. Sensory evaluation resulted that sunsik-type cereal bars showed the high quality Score.

Evaluation on Shear Behaviors of the Dapped Ends of Domestic Composite Double Tee Slabs under the Short-Term Loading (단기하중하의 국내 합성 더블티 슬래브 댑단부 전단거동 평가)

  • 유승룡
    • Journal of the Korea Concrete Institute
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    • v.14 no.5
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    • pp.774-781
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    • 2002
  • Shear behaviors of eight dapped ends of four full-scale domestic single-tee slabs were evaluated. The dapped ends with 10cm topping concrete were designed based on live load requirements for the domestic parking lot of m 500kgf/㎡ and for the large market of 1,200 kgf/㎡. All specimens were designed by the ACI 318-99 design. The variations of the experiment were the shape of hanger reinforcements as followings: 1) general PCI design method(currently used in domestic), 2) 90 degree bent-up, 3) 60 degree bent-up. All experiments were conducted with 1.2 m shear span. The results obtained in this study were 1) all specimens fully complied with the shear strength requirements as specified by ACI 318-99 except for one strand bond slip specimen, 2)a specimen with the 60 degree bent up hanger reinforcing detail showed the best shear behaviors under full service and ultimate load, and 3)a specimen with the 90 degree bent up hanger reinforcing detail resulted in the worst shear behaviors.

Nonlinear Analysis for Negative Moment Distribution of MRS Slab End Joints (비선형 해석에 의한 MRS 슬래브 단부 접합부의 모멘트 분포 연구)

  • Moon, Jeong-Ho;Oh, Young-Hun;Lim, Jae-Hyung
    • Journal of the Korea Concrete Institute
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    • v.23 no.2
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    • pp.177-184
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    • 2011
  • This paper describes an analytical study on the design approach of PC system with continuous connections at member ends. In multi-ribbed moment resisting slab (MRS) system, double tee members are connected continuously over inverted tee beams with the continuous reinforcements placed within topping concrete. Thus, negative moments are concentrated within the narrow connection area. In order to propose a design method, experimental results of the companion study were examined using detailed nonlinear analysis. Then nonlinear static analysis was used to evaluate the partial continuity effect and the moment redistribution mechanism. Material and cross sectional properties were obtained from experimental results of the companion study. Plastic hinge properties for nonlinear static analysis were modeled with cracking moment, nominal moment, corresponding member deformations, etc. The analysis results showed that a large amount of negative moment of MRS slab can be reduced by applying partial continuity and moment redistribution in MRS joint.

Review on Japchae in Cook Books Published during 1600s-1960s (1600년대~1960년대 조리서에 수록된 잡채의 문헌고찰)

  • Lee, Kyong Ae
    • Korean journal of food and cookery science
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    • v.29 no.4
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    • pp.377-385
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    • 2013
  • The changes in ingredients, seasonings and cooking methods of Japchae in Korean cook books published from the 1600s to the 1960s were investigated in this study. Japchae was a royal dish enjoyed by Kwanhaegun of Joseon Dynasty and interesting historical story is contained in it. Kwanghaegun Ilgi in 1608 showed that Japchae was Kwanghaegun's favorite dish. Therefore, it has been thought that Japchae was created in the 17th century. Wonhaengeulmyojeongrieugye in 1796 described bellflower Japchae and mungbean sprout Japchae. The traditional Japchae was made without glass noodle called dangmyeon. Eumsikdimibang in 1670 first introduced traditional Japchae, which was made with 20 different ingredients and then served with topping sauce made of pheasant broth, strained soybean paste and wheat flour. Japchae in Kyugonyoram(1896) was prepared by mixing mungbean sprout, watercress, gonjasoni, tripe and yukhwe with mustard. The current style Japchae with glass noodle first appeared in the 1920s and became popular in the 1950s because the traditional Japchae was described in cook books until the 1940s. There were two ways of preparing current style Japchae. Yijogungjeongyoritonggo in 1957 described Japchae was made by mixing the boiled glass noodle with other ingredients and seasonings together. On the other hand, Japchae in Urinaraeumsikmandeuneunbeob(1960) was prepared by seasoning first with other ingredients, and then mixing boiled glass noodle. A variety of ingredients - vegetables, mushrooms, meat, fish, pheasant, beef tong, sea cucumber, gonjasoni and pear - has been used to prepare Japchae. Japchae has been seasoned with ginger, soy sauce, black pepper, sesame salt, sesame oil, oil, leek, garlic, salt, sugar, vinegar and mustard. Egg strips, pine nut, thin strips of Shiitake and stone mushroom, red pepper threads, Chinese pepper(cheoncho), black pepper and ginger were used for garnishing.

Structural Performance Evaluation on Flexural and Shear Capacity for Weight Reducing Steel Wire-Integrated Void Deck Plate Slab (자중저감 철선일체형 중공 데크플레이트 슬래브의 휨 및 전단내력에 대한 구조성능평가)

  • Kim, Sang-Seup;Ryu, Deog-Su;Boo, Yoon-Seob
    • Journal of Korean Society of Steel Construction
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    • v.24 no.4
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    • pp.411-422
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    • 2012
  • The purpose of this study is to evaluate the flexural and shear capacity of steel wire-integrated void deck plate slabs. In order to evaluate flexural and shear capacity, we make five 150mmspecimens and three 200mmspecimens by slab depth as main variable. Each series of specimen is comprised of an existing steel wire-integrated deck-plate slab and two specimens using topping depth as variable. From the series of experiments, steel wire-integrated void deck plate slabs has any decline in flexural and shear performance. Therefore, a void-deck-plate slab which inserts Omega-steel plate showed reducing a using concrete-volume and had flexural and shear capacity following existing steel wire-integrated deck-plate.