• Title/Summary/Keyword: Prestressed Concrete Box Girder Bridge

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Analysis of PSC Box Girder Anchorage Zone using FEM and 2D SUB-3D STM Approach (유한요소법 및 유사 3 차원 스트릿-타이 모델 방법을 이용한 PSC 박스거더 정착부의 해석)

  • Yun, Young-Mook;Kim, Seung-Eock;Oh, Jin-Woo;Park, Jung-Woong
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.4 no.2
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    • pp.113-129
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    • 2000
  • This study evaluates the behavior and strength of an anchorage zone of the prestressed concrete box girder bridge on the Kyungboo highway railroad using the 2D SUB-3D STM approach and a linear elastic finite element analysis. The 2D SUB-3D STM approach utilizes several two-dimensional sub strut-tie models that represent the compressive and tensile stress flows of each projected plane of the three-dimensional structural concrete in the selection of a three dimensional strut-tie model, evaluation of the effective strengths of the concrete struts, and verification of the geometric compatibility condition and bearing capacity of the critical nodal zones in the selected three-dimensional strut-tie model. The finite element analysis uses an 8-node brick element and the longitudinal prestressing force is considered as the equivalent nodal force. Analysis results show that the 2D SUB-3D STM approach and linear elastic finite element method can be effectively applied to the analysis and design of three-dimensional structural concrete including a prestressed concrete box girder anchorage zone.

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Reliability-Based Assessment of Structural Safety of Regid-Frame-Typed Segmental PSC Box Girder Bridges Erected by the FCM during Construction (FCM에 의한 라멘식 세그멘탈 PSC박스거더 교량의 신뢰성에 기초한 시공간 구조안전도평가)

  • Cho, Hyo-Nam;Joo., Hwan-Joong;Park, Kyung-Hoon;Moon, Kyung-Ho
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.6 no.1
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    • pp.131-140
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    • 2002
  • In this paper, a limit state model based on the analysis of structural behavior of segmental prestressed concrete box girder bridges and reliability-based safety assessment method are proposed for the bridges erected by free cantilever method. Strength limit state models for prestressed concrete box girder and rigid-frame type columns are developed for a structural safety assessment during construction. Based on the proposed limit state models, the reliability of the bridge is evaluated by using the Advanced First Order Second Moment method. The proposed model and method are applied to the Seo-Hae Grand Bridge built by FCM in order to verify its effectiveness in the safety assessment during construction of the kind of bridges. The sensitivity analyses of the main parameters are also performed in order to identify the important factors that need to be controlled for the safety of the bridges during construction.

A Study on the Optimal Design of Prestressed Concrete Box Girder Bridges (프리스트레스트 콘크리트 박스 거더 교량의 최적설계에 관한 연구)

  • Noh, Kum-Rae;Yun, Hee-Taek;Park, Sun-Kyu
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.4 no.2
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    • pp.139-149
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    • 2000
  • In the preliminary design stage of prestressed concrete (PSC) box girder bridges, the design factors decided by inexperience designer could heavily affect to the results of final design. There is a possibility that the design ends up with an excessively wasteful design. To achieve an economical design with preventing an excessive design, the optimal design technique has been developed using ADS optimal program and SPCFRAME in this study. The objective function for the optimal design problem is the material cost of box girders and constrained functions are constituted with design specifications and workability. The Sequential Unconstraint Minimization Technique (SUMT) is used for the optimal design in this study. We designed an uniform cross-section bridge and an ununiform cross-section bridge in the same design condition by optimal design technique developed in this study. Analyzing the results obtained for various tendon layouts, we suggest a standard tendon layout which gives the most effective structural behavior.

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Transverse Analysis of Prestressed Concrete Box Girder High-Speed Railway Bridges (고속전철 PSC 박스거더 교량의 횡방향 해석)

  • 김병석;김영진;박성용
    • Proceedings of the KSR Conference
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    • 1998.11a
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    • pp.47-53
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    • 1998
  • Many kinds of methods have been developed to carry out transverse analysis of prestressed concrete(PSC) box girder bridges. However, most bridge engineers only use the simple frame model to analyze PSC box girder in transverse direction because of its simplicity and easy usage. But, this frame model has many problems such that it can't consider warping, distortion and longitudinal load distribution. In this study, the results from simple frame model and 3-dimensional shell model with UIC load are compared to show its validity. The results from frame model are slightly larger than those of shell model in symmetric loading case. But, positive bending moment of top slab is larger in shell model than frame model in case subject to anti-symmetric loading. It shows that simple frame model can't always give conservative results, so a practical tool whose treatment is easy and whose product is reliable shall be developed as soon as possible.

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3-D Behavior and Strut-and-Tie Model Analysis of Diaphragm in PSC Train Bridge (PSC철도교량 격벽부의 3차원 거동 및 스트럿-타이 모델 해석)

  • 송하원;변근주;김형운;김영훈
    • Proceedings of the KSR Conference
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    • 1998.05a
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    • pp.564-571
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    • 1998
  • The function of diaphragms at abutments and piers of prestressed concrete (PSC) box girder train bridge is to transfer forces from the superstructure onto bearings or column and to stiffen the superstructure cross-section against in-plane deformation. Due to large stress disturbance at diaphragm, the design for the diaphragm using conventional design method is relatively irrational than designs for other structual members. And, due to contribution to boundary condition of deck slab by the diaphragm, the behavior of deck slab near the diaphragm is different from behavior of the deck slab obtained from two dimensional analysis of the bridge, which is basis far the design of deck slab. In this paper, three dimensional behavior of deck slab near diaphragm of PSC box girder train bridge constructed by the precast span method are analyzed by using three dimensional finite element modeling. Then, strut-and-tie model is applied to design the diaphragm of PSC box girder train bridge. The modeling techniques in this paper can be applied effectively to examine the causes of cracks at deck slab near diaphragm and to design diaphragm rationally.

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Current Status and Analysis of PSC Bridge in Korea (국내 프리스트레스트 콘크리트 교량 현황조사 및 분석)

  • Son, Hyeok-Soo;Oh, Myung-Seok;Yoon, Cheol-Kyun;Kim, Ik-Su;Kim, Jin-Woo
    • Proceedings of the Korea Concrete Institute Conference
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    • 2010.05a
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    • pp.23-24
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    • 2010
  • In this research, the comparison and analysis of domestic prestressed concrete bridges were performed with major variations of superstructure type, and span lengths using the 'current status of roadbridge and tunnel' informations provided by MLTM and STATISTICS KOREA. As a result of analysis, steel box girder bridges with 50~100m span length represent about 76% of bridges, but prestressed concrete bridges represent a relatively smaller percentage. In order to replace steel box girder bridges with prestressed concrete bridges, it is necessary to develop prestressed concrete bridges with high-strength tendons and concrete.

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Evaluating fire resistance of prestressed concrete bridge girders

  • Zhang, Gang;Kodur, Venkatesh;Hou, Wei;He, Shuanhai
    • Structural Engineering and Mechanics
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    • v.62 no.6
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    • pp.663-674
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    • 2017
  • This paper presents an approach for evaluating performance of prestressed concrete (PC) bridge girders exposed to fire. A finite element based numerical model for tracing the response of fire exposed T girders is developed in ANSYS. The analysis is carried out in three stages, namely, fire temperature calculation, cross sectional temperature evaluation, and then strength, deformation and effective prestress analysis on girders exposed to elevated temperatures. The applicability of the computer program in tracing the response of PC bridge girders from the initial preloading stage to failure stage, due to combined effects of fire and structure loading, is demonstrated through a case study, and validated by test data of a scaled PC box girder under ISO834 fire condition. Results from the case study show that fire severity has a significant influence on the fire resistance of PC T girders and hydrocarbon fire is most dangerous for the girder. The prestress loss caused by elevated temperature is about 10% under hydrocarbon fire till the girder failure, which can lead to the increase in deflection of the PC girder. The rate of deflection failure criterion is suggested to determine the failure of PC T girder under fire.

Distribution of Time-dependent Strains In the Top Slab of PSC Box Girder Bridge (PSC박스거더교 상부슬래브에서의 시간의존적 변형률 분포)

  • Kim, Young-Jin;Kim, Byung-Suk;Kawrk, Jong-Won
    • Proceedings of the Korea Concrete Institute Conference
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    • 2006.05a
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    • pp.538-541
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    • 2006
  • PSC(Prestressed Concrete) box girder bridges have been widely applied in Korea. A number of these bridges have been built by the segmental construction method in the longitudinal direction and(or) vertically along the cross-sectional depth with MSS(Moving Scaffolding System). An actual 2-span continuous PSC box girder bridge of Kyeongbu high speed railway was selected and instrumented with 96 vibrating wire embedded type strain gauges and 2 thermocouples. The long-term behavior of the bridge was monitored through two major points located at mid-span of the first span and at the internal support. Data collection started just after the casting of the first segment (U section). Concrete strain and temperature data were gathered regularly by a data logger (CR10) during 600 days under and after construction. According to this measurement, the parabolic longitudinal strain distribution in the top slab at mid-span is shown. And also, the same distribution at the interior support is shown. The compressive strains at the cantilever region are larger than at the web position and the internal part in the top slab. Strain difference largely happened during the early construction period.

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The Cross Section Optimization of P.C Box-Girder Bridge Constructed by Free Cantilever Method (FCM 으로 가설되는 P.C 박스거더교의 횡단면 최적설계)

  • 방명석;김일곤;조현준
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1991.04a
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    • pp.56-60
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    • 1991
  • Free Cantilever Method(FCM) is one of the most effective construction methods when precast prestressed concrete box girders are erected in the construction site. The special feature of FCM is that precast segments are erected in cantilever on the pier and connected in the middle of span to form the complete superstructure. Therefore each structural subsystem will be shown in each construction step and it should be analyzed for design whenever the segment is erected. In this study, the computer program was developed to optimally design the P.C box girder bridge considering tile construction sequence and verified by comparing the calculated results with the data of existing P.C box girder bridges. the sensitivity analysis was performed to show the efficiency of the developed program.

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