• Title/Summary/Keyword: Construction Sequence

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Thermal Stresses of Roller Compacted Concrete Dam Considering Construction Sequence and Seasonal Temperature (시공단계 및 계절별 온도영향을 고려한 롤러다짐콘크리트댐의 온도응력 해석)

  • Cha, Soo-Won;Jang, Bong-Seok
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.28 no.6A
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    • pp.881-891
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    • 2008
  • The purpose of the present study is to investigate the influence of seasonal temperature variation on the thermal stresses in roller compacted concrete dam(RCD) structures. Using the finite element code, DIANA performs 2-D transient temperature and resultant stress analysis for RCD. Time variability of the mesh geometry is considered in order to simulate successive phases of the structure's construction. The main analysis variables are construction sequence, concrete temperature and ambient temperature. The results show principal tensile stress of hot-weathering concrete is higher than that of cold-weathering concrete. In some case the index of thermal cracking excesses 1.0, RCD also needs thermal management on placing temperature according to weather condition.

Identifying Correction Range of Geomagnetic Field for Indoor Positioning of Workers at Construction Site (건설현장 내 작업자 실내측위를 위한 지구자기장 보정 범위 도출)

  • Kim, Hyeonmin;Ahn, Heejae;Lee, Changsu;Kim, Harim;Ko, Youngwoong;Cho, HunHee
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2022.11a
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    • pp.93-94
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    • 2022
  • Although various studies about indoor positioning systems, such as beacon and Wifi, have been conducting for indoor positioning of workers at construction sites, these systems have limitations in terms of accuracy or economics. To overcome these limitations, geomagnetic field sequence-based indoor positioning technology can be a good alternative. However, it is necessary to correct the geomagnetic field near the construction material stocking area since the geomagnetic field can be distorted near construction materials such as rebars. Therefore, this study conducted an experiment for identifying correction range of geomagnetic field near the construction material stocking area. It was analyzed that the geomagnetic field should be corrected up to 60cm in the horizontal direction from the stocking point if the height of stocking area for rebars is 40cm or more. This study can be used for important reference for development of geomagnetic field sequence-based indoor positioning technology suitable for construction sites.

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THE CONSTRUCTION OF SOME LEVEL ARTINIAN O-SEQUENCES

  • Shin, Yong-Su
    • Journal of applied mathematics & informatics
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    • v.20 no.1_2
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    • pp.541-548
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    • 2006
  • We find a graded Artinian level O-sequence of the form $H\;:\;h_0\;h_1\;\cdots\;h_{d-1}\;h_d\cdots$ $^{(d+1-1_)-st}h_d$ < $h_{d+s}$ not having the Weak-Lefschetz property. We also introduce several algorithms for construction of some examples of non-unimodal level O-sequences using a computer program called CoCoA.

A preliminary study on the excavation sequence of a room-and-pillar underground structure by the drill-and-blast method (발파 굴착에 의한 주방식 지하구조물의 굴착공기 분석 연구)

  • Lee, Chulho;Hyun, Younghwan;Song, Junho;Chang, Soo-Ho
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.17 no.6
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    • pp.605-614
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    • 2015
  • A room-and-pillar underground structure is characterized by its grid-type array of room and pillar. As a result, its construction and economical efficiency can be governed by excavation sequence. In this study, the construction period by the drill and blast method which can be treated as a main sequence for excavation was examined by considering the regulation for blasting and construction standard of estimation in Korea. To evaluate the construction period for the room-and-pillar underground structure constructed in 4 kinds of square-type area ($30{\times}30{\sim}57{\times}57m$), the concurrent excavation pattern which was suggested in the previous researches was used. From the suggested condition, the total construction period by drill-and-blast method can be estimated with the consideration of the construction area, number of jumbo drill and faces in operation.

Construction of Jacket Matrices Based on q-ary M-sequences (q-ary M-sequences에 근거한 재킷 행렬 설계)

  • S.P., Balakannan;Kim, Jeong-Ki;Borissov, Yuri;Lee, Moon-Ho
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.45 no.7
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    • pp.17-21
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    • 2008
  • As with the binary pseudo-random sequences q-ary m-sequences possess very good properties which make them useful in many applications. So we construct a class of Jacket matrices by applying additive characters of the finite field $F_q$ to entries of all shifts of q-ary m-sequence. In this paper, we generalize a method of obtaining conventional Hadamard matrices from binary PN-sequences. By this way we propose Jacket matrix construction based on q-ary M-sequences.

New Construction Method for Quaternary Aperiodic, Periodic, and Z-Complementary Sequence Sets

  • Zeng, Fanxin;Zeng, Xiaoping;Zhang, Zhenyu;Zeng, Xiangyong;Xuan, Guixin;Xiao, Lingna
    • Journal of Communications and Networks
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    • v.14 no.3
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    • pp.230-236
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    • 2012
  • Based on the known binary sequence sets and Gray mapping, a new method for constructing quaternary sequence sets is presented and the resulting sequence sets' properties are investigated. As three direct applications of the proposed method, when we choose the binary aperiodic, periodic, and Z-complementary sequence sets as the known binary sequence sets, the resultant quaternary sequence sets are the quaternary aperiodic, periodic, and Z-complementary sequence sets, respectively. In comparison with themethod proposed by Jang et al., the new method can cope with either both the aperiodic and periodic cases or both even and odd lengths of sub-sequences, whereas the former is only fit for the periodic case with even length of sub-sequences. As a consequence, by both our and Jang et al.'s methods, an arbitrary binary aperiodic, periodic, or Z-complementary sequence set can be transformed into a quaternary one no matter its length of sub-sequences is odd or even. Finally, a table on the existing quaternary periodic complementary sequence sets is given as well.

New Technical Method in Incheon Bridge (인천대교와 신기술들)

  • Yoon, Man-Keun
    • Journal of the Korean Professional Engineers Association
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    • v.39 no.6 s.189
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    • pp.42-48
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    • 2006
  • This is briefly to introduce about design and construction method newly adopted in Incheon bridge construction site. The Incheon Bridge Project are divided into 3 parts, that is Cable Stayed Bridge. Viaduct Bridge and Approach Bridge. In this paper, we will describe overview and construction sequence of each kind part.

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The Reasonable Concrete-Placing Methods and Sequences of Composite Steel Bridge (강합성형 교량의 합리적인 타설방법과 순서에 관한 연구)

  • Jo, Byung-Wan;Seo, Sug-Gu
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.3 no.2
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    • pp.205-212
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    • 1999
  • Recently, unexpected cracks in the concrete deck slab of composite steel bridges have been widely reported at an early age of concrete placing due to the concrete placing sequence and methods. Accordingly, the analytical research was carried out to verify the negative moment at an internal supports due to the several concrete pouring sequence and to determine the reasonable concrete placing method on the deck slab of composite steel bridge. The results show that the conventional concrete-placing method, which pours concrete first on the positive moment regions and then negative regions, leads to the minimum moment at an internal supports. However, the conventional method produces two impractical construction joints on every spans and makes field engineer to pour concrete continuously. In conclusion, this concrete-placing method was verified to be reasonable only when the construction joint was placed at the $\frac{5}{8}l{\sim}\frac{6}{8}l$ location of the middle span.

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