• Title/Summary/Keyword: design provisions

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Effect of high-strength concrete on shear behavior of dry joints in precast concrete segmental bridges

  • Jiang, Haibo;Chen, Ying;Liu, Airong;Wang, Tianlong;Fang, Zhuangcheng
    • Steel and Composite Structures
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    • v.22 no.5
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    • pp.1019-1038
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    • 2016
  • The use of high-strength concrete (HSC) in precast concrete segmental bridges (PCSBs) can minimize the superstructure geometry and reduce beam weight, which can accelerate the construction speed. Dry joints between the segments in PCSBs introduce discontinuity and require special attention in design and construction. Cracks in dry joints initiate more easily than those in epoxy joints in construction period or in service. Due to the higher rupture strength of HSC, the higher cracking resistance can be achieved. In this study, shear behavior of dry joints in PCSBs was investigated by experiments, especially focusing on cracking resistance and shear strength of HSC dry joints. It can be concluded that the use of HSC can improve the cracking resistance, shear strength, and ductility of monolithic, single-keyed and three-keyed specimens. The experimental results obtained from tests were compared with the AASHTO 2003 design provisions. The AASHTO 2003 provision underestimates the shear capacity of single-keyed dry joint C50 and C70 HSC specimens, underestimates the shear strength of three-keyed dry joint C70 HSC specimens, and overestimates the shear capacity of three-keyed dry joint C50 HSC specimens.

Simplified elastic design checks for torsionally balanced and unbalanced low-medium rise buildings in lower seismicity regions

  • Lam, Nelson T.K.;Wilson, John L.;Lumantarna, Elisa
    • Earthquakes and Structures
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    • v.11 no.5
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    • pp.741-777
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    • 2016
  • A simplified approach of assessing torsionally balanced (TB) and torsionally unbalanced (TU) low-medium rise buildings of up to 30 m in height is presented in this paper for regions of low-to-moderate seismicity. The Generalised Force Method of Analysis for TB buildings which is illustrated in the early part of the paper involves calculation of the deflection profile of the building in a 2D analysis in order that a capacity diagram can be constructed to intercept with the acceleration-displacement response spectrum diagram representing seismic actions. This approach of calculation on the planar model of a building which involves applying lateral forces to the building (waiving away the need of a dynamic analysis and yet obtaining similar results) has been adapted for determining the deflection behaviour of a TU building in the later part of the paper. Another key original contribution to knowledge is taking into account the strong dependence of the torsional response behaviour of the building on the periodic properties of the applied excitations in relation to the natural periods of vibration of the building. Many of the trends presented are not reflected in provisions of major codes of practices for the seismic design of buildings. The deflection behaviour of the building in response to displacement controlled (DC) excitations is in stark contrast to behaviour in acceleration controlled (AC), or velocity controlled (VC), conditions, and is much easier to generalise. Although DC conditions are rare with buildings not exceeding 30 m in height displacement estimates based on such conditions can be taken as upper bound estimates in order that a conservative prediction of the displacement profile at the edge of a TU building can be obtained conveniently by the use of a constant amplification factor to scale results from planar analysis.

A Study on the Improvement Direction through the Present Status of Nursing Home - Focus on the Nursing Home in Chungcheongbuk-do - (노인요양시설의 건축현황 및 개선방향에 관한 연구 - 충청북도 노인요양시설을 중심으로 -)

  • Lee, Wan-Geon
    • Korean Institute of Interior Design Journal
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    • v.19 no.3
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    • pp.242-250
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    • 2010
  • Recently, the long-term care insurance for the elderly was carried out according to the elderly is increased rapidly and the formation of sympathy that a nation and society try commonly to share health and welfare promotion of the elderly. The purpose of this study is to analyze the present status of nursing home after that the long-term care insurance is enforced in chungcheongbuk-do and to utilize as basic data. The study limited its survey to those facilities that refer to the Ministry of Health and Welfare data, that had the capacity of more than 50 people. The result are as followings. Firstly, most of the nursing home were located on the outskirts of the city. But it must be constructed in the city center if the recent deinstitutionalization trend is reflected. Secondly, notwithstanding the provisions of the Elderly Welfare Law, if the Livability and amenity are considered, the plan of a single or a twin room is needed. The ondol(溫突) system bedroom for the safety of the elderly had to be planned and for the color planning of a bedroom, a heating, the furniture, the form of a door, corridors, etc. should be partly improved. The fastener in which it is appropriate for the main exit, a stair, an elevator, the lighting device, and etc. is needed and the installation of a wandering path for the dementia patient and etc. is required. Thirdly, most of the dining room arranged on the first floor but it is not nearly used and it used for employee or the other use. Therefore, we have to consider the system in which it can deliver the meal to a bedroom. If the smell of the elderly and etc. is considered, the sufficient height of the floor should be reflected for the ventilation equipment. Lastly, The improvement of the existing law are required.

An Analysis of Functional Requirements for Electronic Records Management Systems: Based on the Records Management Principles Extracted from ISO 15489 (전자기록관리시스템(ERMS) 설계표준의 기능요건 분석-ISO 15489를 기준으로-)

  • Lee, So-Yeon;Kim, Ja-Kyoung
    • Journal of the Korean Society for information Management
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    • v.21 no.3
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    • pp.227-250
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    • 2004
  • In order to design effective electronic records management systems, it is viable to consider both traditional principles of records management, proven to be effective, and the characteristics of digital information. ISO 15489, an international standard for records management, is acknowledged as the most useful guidelines for this goal. The present study extracted basic principles of electronic records management from its provisions of 7 functional steps. It then compared the principles to system requirements of three system design criterion, developed by Department of Defense(U.S.A.) Public Records Office(Britain). and European Union respectively. Common requirements, included in all three criterion. were then searched in the Korean standard of developing automated systems for records centers. Finally, suggestions were made to develop a Korean standard for electronic records management system, elaborating from the core requirements of the system found by the present study.

Study on Reinforcement Effect of Circular RC Columns by Helical Bar Under Cyclic Lateral Load (반복 횡하중을 받는 원형 철근콘크리트 기둥의 Helical Bar 보강효과에 대한 연구)

  • Kim, Seong-Kyum;Park, Jong-Kwon;Han, Sang-Hee;Kim, Byung-Cheol;Jang, Il-Young
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.18 no.1
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    • pp.48-58
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    • 2014
  • In this study, quasi-static according to the displacement-controlled (strain control) method tests on RC columns for seismic reinforcement performance in accordance with the provisions of the seismic design and construction before 1992 design code for highway bridges in korea. Used reinforcement that improves the performance of Inorganic Helical Bar, a kind of alloy steel, circular columns were tested outside the seismic reinforcing. In the experiment, fracture behavior, lateral load-displacement relation, ductility and energy assessment evaluation was performed through tests. The variables in experimental are section force of reinforcement, spiral reinforcement spacing, reinforcement method. Improved seismic performance and effect were confirmed through quasi-static test experiments. The results of study confirmed determination the appropriate size of reinforcement, reinforcement forces, spacing and selection of the type required, furthermore, not only mechanical reinforcement but also substitution of high-strength concrete reinforced with concrete cover improved seismic performance.

A Development of a Web Based Supporting System for Writing Construction Project Specification (Web기반 공사시방서 작성 시스템 개발 방안)

  • Kim Kyoon-Tai;Kim Tae-Song;Koo Jai-Dong
    • Proceedings of the Korean Institute Of Construction Engineering and Management
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    • autumn
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    • pp.501-506
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    • 2001
  • The Korean government established a domestic specification system, and regulated that owner should produced construction project specifications, instead of special provisions, in design phase, January 1998. But in Korea the ability of construction engineers for construction project specification are insufficient. So the government had built up a database of standard specifications and developed a supporting system for writing construction project specification(SPECMAKE) in 1999. However, it is a PC base stand-alone system, so it is not convenient to update the database. In order to overcome these limitations, the purpose of this paper builds up a database of construction criteria and develops a automatic writing system for construction project specification on web base. The database contains standard specifications, design and construction guidelines related with construction business. And this paper describes the frameworks, the components, and the functions of the specifications writing system for the construction projects.

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Crime Prevention by Using CPTED and Improvement (환경설계를 통한 범죄예방 및 개선방안)

  • Park, Kwang-Hyun
    • Journal of Digital Contents Society
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    • v.18 no.4
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    • pp.733-738
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    • 2017
  • This study is to find out empirically how the fear of crime is affected by the level of recognition of people. CPTED elements including natural surveillance, access control, utilization enhancement, territoriality securement, etc. Safety of residents could be considered and then increased when we plan, design, and operate a city. In Korea, CPTED is currently being applied to every town. However, it is not systemized and neither efficient, for there are no constraint provisions, and the foreign cases are not specifically customized to the current situation of the country. This study, therefore, aims to find the limits from analyzing related laws and regimes, administrative regulations, and applied cases, and to deduct improvement plans based on examined foreign cases.

An Assessment Study of Seismic Resistance of Two-story Wood-frame Housing by Shaking Table Tests

  • Ni, Chun;Kim, Sang-Yeon;Chen, Haijiang;Lu, Xilin
    • Land and Housing Review
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    • v.3 no.1
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    • pp.79-82
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    • 2012
  • While there exists a relatively large body of technical information for the engineered design of wood-frame buildings to resist seismic ground motions, the quantitative assessment of seismic resistance of conventional houses built by prescriptive requirements is less well understood. Forintek Canada Corp., in collaboration with other research and industry partners, has embarked on a research project to address this topic. This paper will report on the seismic shake table tests of a full-scale wood-frame building. The two-story specimen, $6m{\times}6m$ in plan, was built on the seismic shake table at Tongji University in Shanghai, China, according to Part 9 of the 1995 National Building Code of Canada and shaken uni-directionally in each of the two principal directions. Three different seismic table motions were applied at increasing peak ground motion amplitudes up to 0.40 and 0.50 g. The specimen was repaired after the above sets of seismic table motions, and successive runs were conducted for increased door openings. Measurements included specimen accelerations, displacements and anchorage forces. Static stiffness of the specimen was measured at low force levels, and natural frequencies were measured after each seismic loading stage by applying low-level random excitation. The results presented consist of the capacity spectra of the shake table tests, changes in specimen stiffness and natural frequencies with increasing seismic loading. These results and those from other recent shake table tests elsewhere will be compared with simplified engineering calculations based on codified values of strength, and on that basis preliminary conclusions will be drawn on the adequacy of the current code provisions and design guides in Canada and the USA for conventional wood-frame construction.

Study on the Decision of Watergate Stage Using Inundation Simulation for Inland (내수침수모의를 통한 배수문 높이결정에 관한 연구)

  • Choo, Tai Ho;Yun, Gwan Seon;Yoon, Hyeon Cheol
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.2
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    • pp.1149-1156
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    • 2014
  • In order to reduce flood damages, there should demand an appropriate design such as enlarging a bank, dredging a river bottom, building a hydraulic structure and so on. The installation locations about the Watergate are listed of the seven provisions in the river design standard, but it is not detailed. In order to compute proper place considering landuse and basin characteristics of inlands, internal inundation modeling that should be performed is regarded with quantitative evaluation. Anyway, that is very complex and taking a long time because that has to consider hydraulic and hydrologic characteristics. In the current study, therefore, the simple and convenient method for internal inundation modeling was proposed to overview the Watergate location.

Estimating uncertainty in limit state capacities for reinforced concrete frame structures through pushover analysis

  • Yu, Xiaohui;Lu, Dagang;Li, Bing
    • Earthquakes and Structures
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    • v.10 no.1
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    • pp.141-161
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    • 2016
  • In seismic fragility and risk analysis, the definition of structural limit state (LS) capacities is of crucial importance. Traditionally, LS capacities are defined according to design code provisions or using deterministic pushover analysis without considering the inherent randomness of structural parameters. To assess the effects of structural randomness on LS capacities, ten structural parameters that include material strengths and gravity loads are considered as random variables, and a probabilistic pushover method based on a correlation-controlled Latin hypercube sampling technique is used to estimate the uncertainties in LS capacities for four typical reinforced concrete frame buildings. A series of ten LSs are identified from the pushover curves based on the design-code-given thresholds and the available damage-controlled criteria. The obtained LS capacities are further represented by a lognormal model with the median $m_C$ and the dispersion ${\beta}_C$. The results show that structural uncertainties have limited influence on $m_C$ for the LSs other than that near collapse. The commonly used assumption of ${\beta}_C$ between 0.25 and 0.30 overestimates the uncertainties in LS capacities for each individual building, but they are suitable for a building group with moderate damages. A low uncertainty as ${\beta}_C=0.1{\sim}0.15$ is adequate for the LSs associated with slight damages of structures, while a large uncertainty as ${\beta}_C=0.40{\sim}0.45$ is suggested for the LSs near collapse.