• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.29 no.3A
• /
• pp.235-241
• /
• 2009

PSC girder bridge is known to be more economical than other types of bridges and has been usually applied to a span range of 25 m to 35 m according to the standard shapes for highway bridges in Korea. The spans of the recently developed new types of PSC girders are also limited to 50 m at most. In this study, therefore, feasibility of the long-span PSC girder that reaches more than 50 m is investigated by applying several strategies from the perspectives of materials, design and construction. A systematic procedure is proposed that can be used to assess the effect of each strategy on the span. The proposed scheme adopts a graphical approach that represents a relationship between the number of prestressing tendons and the span, and is derived on a basis of safety assessment equations of the girder in each stage of fabrication and in service. In the companion paper, the amount of span extension is quantitatively evaluated by applying the proposed scheme into a sample PSC girder bridge.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.20 no.3
• /
• pp.49-57
• /
• 2016

This study intended to analyze reinforcement effects of PSC I girder bridges to which prestresses are introduced using V type of external strands. So that series of bridge loading tests are carried out on existing PSC I girder bridge for the cases of before-reinforcement and reinforcement. The measured results from tests being analyzed and compared with the ones from MIDAS structural analyzing program, the reinforcing effects of the reinforcement system adopted in this study were investigated. It is found out that when the V type systems are applied to the bridge girders, the slope of load distribution factor curves become lower improving soundness of bridge upper structure. And also it is confirmed that the reinforcement system in this study can be taken as helpful for improvement of both flexural and shear ability of PSC I girder bridges, as well as dynamic behavior. Furthermore it is found when the elastic pads are applied to the system, dynamic reinforcing effects are maximized.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.25 no.1
• /
• pp.67-74
• /
• 2021

This paper evaluated the structural safety of an aging PSC I-girder bridge with rebar corrosion in the deck. The geometry and rebar of the bridge were designed based on an actual PSC I-girder bridge, and the numerical analysis was performed considering the crack of concrete and yielding of steel rebar. According to the evaluation criteria of Korea Infrastructure Safety and Technology Corporation, this study defined two criteria of rebar exposure and corrosion rates to construct a total of 32 corrosion scenarios. Rebar exposure was defined as the exposure of tensile rebars in the bridge deck due to the removal of cover concrete. The results of the analysis showed that the safety and rating factors of the bridge decreased with increasing rebar exposure and corrosion rates. For the rebar corrosion rate more than 50%, the safety grade of the bridge should be carefully evaluated for all the rebar exposure rate. When the rebar corrosion rate exceeds 57%, the bridge was evaluated as E grade regardless of rebar exposure rate. A correlation analysis for a 2% of rebar exposure rate found that the bridge was evaluated as A grade up to 55.8% corrosion rate, C grade up to 56.9%, D grade up to 58.5%, and E grade for corrosion rate greater than 58.5%. This study indicates the necessity of a quantitative evaluation of rebar corrosion for evaluating the structural safety of aging bridges.

• Journal of the Korean Society for Railway
• /
• v.16 no.4
• /
• pp.286-297
• /
• 2013

In this paper we evaluated dynamic stability, considering the effects of modeling and analysis methods on moving load analysis, for which a sophisticated 3 dimensional model of a PSC-I type girder bridge was used. For this purpose, we suggested a reasonable modeling method and the physical properties of the concrete and ballasted track system involved. We also analyzed the response characteristics according to: 1) the type of track system; 2) whether or not the track was modeled; 3) whether or not the distance between the girder center and the bearing were considered; 4) the analysis method (i.e., direct integral and modal analysis); 5) whether or not the frequency was filtered.

• The Journal of the Korea Contents Association
• /
• v.14 no.7
• /
• pp.511-517
• /
• 2014

The superstructure type of the railway bridge in our country, is mainly classified into the box girder and the I-type girder. The box girder is widely used in the high speed railway bridge because of the safety due to dynamic behavior. The I-type girder is used in the conventional railway bridge, and is also divided into the general type and the composite type, and the newly modified types have been developed. According to the current railway bridge design code, the girder design by the span length in various railway bridge types are performed in this study. The suitable girder height by the span length are analyzed, and the comparative analysis of the structural efficiency and the economical efficiency is carried out. From this study, the composite type girder is appeared the good result in respect of the structural efficiency. However, in the economical aspect, the general I-type girder is required less cost than the other types.

• Journal of the Korean Society for Railway
• /
• v.11 no.5
• /
• pp.471-476
• /
• 2008

The superstructure type of the railway bridge in our country, is mainly classified into the box girder and the I-type girder. The box girder is widely used in the high speed railway bridge because of the safety due to dynamic behavior. The I-type girder is used in the conventional railway bridge, and is also divided into the general type and the composite type, and the newly modified types have been developed. According to the current railway bridge design code, the girder design by the span length in various types of railway bridge is performed in is study. The suitable girder height and the construction cost by the span length are analyzed, and the comparative analysis of the structural efficiency and the economical efficiency is carried out. From this study, the composite type girder is appeared the good result in respect of the structural efficiency. However, in the economical aspect, the general I-type girder is required less cost than the other types.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2009.05a
• /
• pp.39-40
• /
• 2009

This study is for development the anchorage that for development and practicality a holed precast prestressed concrete girder for forming an I-type Prestressed concrete girder bridge, in which at least one hole is formed in a body portion of the I-type Prestressed concrete girder.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2004.05a
• /
• pp.528-531
• /
• 2004

Nowadays, many of PSC bridges has constructed because high performance and long span bridge is required. Therefore, it is required that the evaluation of PSC bridges which retain various structure performance. In this study, nonlinear FEM analysis was performed with two parameter, concrete compressive strength and effective prestress force which is dominant factor for evaluating structural behavior of PSC bridge. Concrete compressive strength was adapted between 30Mpa and 100Mpa and effective prestress force was used the value which is considered effective rate for time-dependant effect. In the result of this study, it was showed that concrete compressive strength and effective prestress force is important factor for evaluating structural behavior of PSC bridge.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.42 no.1
• /
• pp.1-9
• /
• 2022

Semi-integral abutment bridges are a type of integral abutment bridges. These bridges eliminate expansion joints on the structure and can be used in situations not suitable for full-integral abutment bridge. Moreover, Semi-integral bridges have excellent maintenance and can be economically constructed. This study is about precast wall-type blocks at each end which provide lateral support for PSC girder, as well as acting as retaining walls to resist longitudinal movement of semi-integral abutment bridge. The end-diaphragm connection between ended blocks of PSC girders can be achieved by in-suit nonshrinkage concrete. The results show that 3-point experiment of end-diaphragm beam have an acceptable performance which is so better than results of structural design. Moreover, the effects of backfill soil on semi-integral abutment bridge constructed are analyzed the behavior according to the temperature changes.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.21 no.4
• /
• pp.325-334
• /
• 2008

The standard prestressed concrete I-girder bridge (PSC I-girder bridge) is one of the most prevalent types for small and medium bridges in Korea. When determining the member forces in a section to assess the safety of girder in this type of bridge, the general practice is to use the simplified practical equations or the live load distribution factors proposed in design standards rather than the precise analysis through the finite element method or so. Meanwhile, the live load distribution factors currently used in Korean design practice are just a reflection of overseas research results or design standards without alterations. Therefore, it is necessary to develop an equation of the live load distribution factors fit for the design conditions of Korea, considering the standardized section of standard PSC I-girder bridges and the design strength of concrete. In this study, to develop an equation of the live load distribution factors, a parametric analysis and sensitivity analysis were carried out on the parameters such as width of bridge, span length, girder spacing, width of traffic lane, etc. As a result, the major variables to determine the size of distribution factors were girder spacing, overhang length and span length in case of external girders. For internal adjacent girders, the determinant factors were girder spacing, overhang length, span length and width of bridge. For internal girders, the factors were girder spacing, width of bridge and span length. Then, an equation of live load distribution factors was developed through the multiple linear regression analysis on the results of parametric analysis. When the actual practice engineers design a bridge with the equation of live load distribution factors developed here, they will determine the design of member forces ensuring the appropriate safety rate more easily. Moreover, in the preliminary design, this model is expected to save much time for the repetitive design to improve the structural efficiency of PSC I-girder bridges.