• Title/Summary/Keyword: Load-bearing capacity

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Internal force monitoring design of long span bridges based on ultimate bearing capacity ratios of structural components

  • Hu, Ke;Xie, Zheng;Wang, Zuo-Cai;Ren, Wei-Xin;Chen, Lei-Ke
    • Structural Monitoring and Maintenance
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    • v.5 no.1
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    • pp.93-110
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    • 2018
  • In order to provide a novel strategy for long-span bridge health monitoring system design, this paper proposes a novel ultimate bearing capacity ratios based bridge internal force monitoring design method. The bridge ultimate bearing capacity analysis theories are briefly described. Then, based on the ultimate bearing capacity of the structural component, the component ultimate bearing capacity ratio, the uniformity of ultimate bearing capacity ratio, and the reference of component ultimate bearing capacity ratio are defined. Based on the defined indices, the high bearing components can then be found, and the internal force monitoring system can be designed. Finally, the proposed method is applied to the bridge health monitoring system design of the second highway bridge of Wuhu Yangtze river. Through the ultimate bearing capacity analysis of the bridge in eight load conditions, the high bearing components are found based on the proposed method. The bridge internal force monitoring system is then preliminary designed. The results show that the proposed method can provide quantitative criteria for sensors layout. The monitoring components based on the proposed method are consistent with the actual failure process of the bridge, and can reduce the monitoring of low bearing components. For the second highway bridge of Wuhu Yangtze river, only 59 components are designed to be monitored their internal forces. Therefore, the bridge internal force monitoring system based on the ultimate bearing capacity ratio can decrease the number of monitored components and the cost of the whole monitoring system.

Theoretical Analysis of Water Hydrostatic Journal Bearings (물 정수압 저널 베어링의 이론적 해석)

  • Park, Seong-Hwan;Park, Sang-Shin
    • Tribology and Lubricants
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    • v.27 no.2
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    • pp.71-76
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    • 2011
  • In this study, the nondimensional load capacity of water hydrodynamic journal bearings is calculated. A generalized coordinate formulation is applied to handle the complexity of bearing geometry. A window-based analysis program is developed to analysis the cylindrical hydrostatic bearings. Load capacities are calculated according to some design parameters such as clearance, diameter of orifice, size of recesses and temperature. The results are presented and discussed.

Load Bearing Capacity Evaluation of Continuous IPC Girder Bridge. (IPC 거더 연속교의 실교량 내하력 평가 연구)

  • Han, Man-Yop;Hwang, Eu-Seung;Jin, Kyung-Seok;Kang, Sang-Hoon;Shin, Jae-Woo
    • Proceedings of the Korea Concrete Institute Conference
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    • 2005.05a
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    • pp.475-478
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    • 2005
  • This study was performed to evaluate about load bearing capacity of continuos IPC Girder Bridge under and after Construction. This is Ichi-1 Bridge that is 2-40m span continuous bridge on a extension road through the Ichun and the Naesa. The result of static loading test to use a 25ton truck after construction, deflection ratio is 0.64 that is $35\%$ and average of response ratio is 0.48$\~$0.89 that is less than theoretical value. The result of dynamic loading test, the number of proper vibrations is 3.06Hz that is like theoretical value 3.61Hz, the modulus of impact is 0.235 that is bigger than specification 0.19. the load bearing capacity is minimum DB-40 that is so big value. In the result, continuos IPC Girder Bridge is safe in short period. we will evaluate long period behavior of continuos IPC Girder Bridge.

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Analytical Study on Effects of Bearing Geometry on Performance of Sliding Thrust Bearings (미끄럼 스러스트베어링의 성능에 미치는 베어링 형상의 영향 해석)

  • Kim, Ho-Jong;Choi, Sung-Pil;Ha, Hyun-Cheon
    • The KSFM Journal of Fluid Machinery
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    • v.9 no.5 s.38
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    • pp.7-13
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    • 2006
  • In the present study, we develop an analysis module to be applicable to design of sliding thrust bearings. The pressure equation is solved by using the finite element method. Average lubricant temperature is obtained from using the energy balance method. The module developed has been applied to three types of thrust bearing, such as tapered-land thrust bearings of angular and diamond types, and tilting-pad thrust bearings. Effects of the dam of the tapered-lad thrust bearings have also been investigated. It has been seen that the tapered-land thrust bearings of angular type result in the highest load capacity, while the tilting pad thrust bearings result in the lowest lubricant temperature. It has also been seen that the dam in the tapered-land thrust bearings increases both the load capacity and lubricant temperature.

Numerical Investigation on Load Supporting Mechanism of a Pile Constructed above Underground Cavity (공동이 존재하는 암반에 시공된 말뚝기초의 하중지지 메카니즘에 관한 수치해석 연구)

  • Choi, Go-Ny;Yoo, Chung-Sik
    • Journal of the Korean Geotechnical Society
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    • v.27 no.1
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    • pp.5-16
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    • 2011
  • This paper presents the results of a three-dimensional finite element analysis on load supporting mechanism of pile constructed above underground cavity in limestone rock formation. Considering a wide range of cavity conditions, the behavior of pile was studied using the bearing capacity, rock yielding pattern, stress distribution and deformation of pile head and the cavity. The results indicate that the load transfer mechanism of pile, rock yielding pattern and the reduction of bearing capacity of pile significantly vary with the location, size and length of cavity. Based on the results, graphical solutions defining the reduction of the bearing capacity with specific cavity conditions were suggested.

Development of Repair System for Drain Pipe to Enhance Safety (하수관거 안전성 향상을 위한 보수 시스템 개발)

  • Chung, Jee-Seung;Kang, Weon-Dae
    • Journal of the Korean Society of Safety
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    • v.26 no.6
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    • pp.45-53
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    • 2011
  • This study was performed to develop repair and reinforcing materials in sewage drain pipe by using 40% of CAC(Calcium Aluminate Cement) and 4% of Polymer Powder. Regarding reinforcing materials to enhance load-bearing capacity, polyester textile and wire mesh were adopted and then they were evaluated by the measurement of deflection and Stress-strain Relationship. Two types of drain pipe made by concrete and PE were considered as plain specimens and then loading test were performed after repaired by CAC mortar impregnated reinforcing materials. As the test results of the load-bearing test on both drain pipe, there was higher load-bearing capacity on the specimen adopted wire mesh but debonding of repair mortar was found due to stiffness of wire mesh. By the way, repair system using CAC mortar impregnated polyster textile without wire mesh showed satisfactory results including bonding and load-bearing capacity regardless substrate, so this repair system using by mixture of CAC mortar and polyster textile is suggested as the reasonable repairing method within this experimental scope.

Bearing Capacity Analysis on Cyclic Loading of Soft Ground by Surface Reinforcement (표층처리지반에서의 반복하중재하시험을 통한 지지력 분석)

  • Kwak, Nokyung;Park, Minchul;Lee, Song
    • Journal of the Korean GEO-environmental Society
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    • v.13 no.6
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    • pp.5-17
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    • 2012
  • The study of surface ground reinforcing method is supposed to be considered preferentially is not satisfied and also doesn't contemplate plastic flow because of repetitive drive of construction equipment. Also, Terzaghi's bearing-capacity equation and Yamanouchi's suggestion have been used to design the surface reinforcement, but most engineers depend on their experience and cases constructed before because of dispersed variables and inappropriate bearing-capacity factors. Hence, plate load test and repetitive plate load test were performed in the field which is reinforced with geotextile, Geogrid whose tensile strength are 200kN/m, 100kN/m and bamboo($0.4m{\times}0.4m$). The object of this study is to evaluate bearing capacity and behaviour of surface ground and to compare each reinforcement form test results. From the results bearing capacity ratio increased by a maximum of 1.5 times with bamboo reinforcement method comparing to others.

Load Carrying Capacity and Failure Mechanism of Geogrid Reinforced Stone Columns : Reduced-Scale Model Tests (지오그리드 보강 Stone Column의 파괴메카니즘 및 지지력 특성 - 축소모형실험을 통한 고찰)

  • Lee, Dae-Young;Song, Ah-Ran;Yoo, Chung-Sik
    • Journal of the Korean Geotechnical Society
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    • v.22 no.10
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    • pp.121-129
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    • 2006
  • Stone column is one of the ground improvement systems which is being used for accelerating consolidation and increasing bearing capacity for settlement sensitive structures like load embankments, bridge abutments, oil storage tanks etc. The effects of this method are enhancement of ground bearing capacity, reduction of settlement, prevention of liquefaction and prevention of lateral ground movement. Recently, geosynthetic reinforced (encased) stone column approach has been developed to improve its load carrying capacity through increasing confinement effect. Although such a concept has successfully been applied in practice, fundamentals of the method have not been fully explored. This paper presents the results of an investigation on the bearing capacity and failure mechanism of geogrid-encased stone column by model tests. The results of the analyses indicated improved bearing capacity of the geogrid reinforced stone column method over the conventional strone column method with no encasing.

Bearing Capacity of SDA Augered Piles in Various Grounds Depending on Water-Cement Ratio of Cement Milk (시멘트밀크 배합비에 따른 다양한 지반 내 SDA매입말뚝의 연직지지력)

  • Hong, Won-Pyo;Lee, Jae-Ho;Chai, Soo-Geun
    • Journal of the Korean Geotechnical Society
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    • v.24 no.5
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    • pp.37-54
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    • 2008
  • The standard construction manual of the SDA (Separated Doughnut Auger) piling method was proposed so that the resisting capacity of the augered piles could work effectively. 438 dynamic pile load tests were performed on 379 test piles, which were installed at 36 sites in Korea by the SDA piling method with application of various water-cement ratio of cement milks. The dynamic pile load test results showed that the bearing capacity of the SDA augered piles depended on the water-cement ratio of cement milks. And couple of the formulas were presented according to water-cement ratio and various grounds to estimate quantitatively both the unit end bearing and the unit frictional capacity of the SDA augered piles. It was also considered that the water-cement ratio of cement milks exerts an influence on the bearing capacity of the SDA augered piles. The presented formulas were compared with the existing formulas, which were presented by several standard design codes to design the augered piles.

Research on axial bearing capacity of cold-formed thin-walled steel built-up column with 12-limb-section

  • Wentao Qiao;Yuhuan Wang;Ruifeng Li;Dong Wang;Haiying Zhang
    • Steel and Composite Structures
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    • v.47 no.3
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    • pp.437-450
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    • 2023
  • A half open cross section built-up column, namely cold-formed thin-walled steel built-up column with 12-limbsection (CTSBC-12) is put forward. To deeply reveal the mechanical behaviors of CTSBC-12 under axial compression and put forward its calculation formula of axial bearing capacity, based on the previous axial compression experimental research, the finite element analysis (FEA) is conducted on 9 CTSBC-12 specimens, and then the variable parameter analysis is carried out. The results show the FEA is in good agreement with the experimental research, the ultimate bearing capacity error is within 10%. When the slenderness ratio is more than 96.54, the ultimate bearing capacity of CTSBC-12 decreases rapidly, and the failure mode changes from local buckling to global buckling. With the local buckling failure mode unchanged, the ultimate bearing capacity decreases gradually as the ratio of web height to thickness increases. Three methods are used for calculating the ultimate bearing capacity, the direct strength method of AISI S100-2007 gives result of ultimate axial load which is closest to the test and FEA results. But for simplicity and practicality, a simplified axial bearing capacity formula is proposed, which has better calculation accuracy with the slenderness ratio changing from 30 to 100.