• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.20 no.5
• /
• pp.593-604
• /
• 2007

Although composite construction has more mechanical advantages compared to noncomposite construction, the design of noncomposite construction for skew bridges with large skew angels has been often checked because composite construction may cause large stresses in the bridge deck. In this study, the analytical model considered dynamic behaviors for noncomposite skew bridges was proposed. Using the proposed analytical model, the validity of the application of noncomposite construction to skew bridges was checked. Also, the effects of interactions between the concrete deck and steel girders such as composite construction, partial composite construction, and noncomposite construction on the dynamic characteristics and dynamic behaviors of simply supported skew bridges were investigated. A series of parametric studies for the total 27 skew bridges was conducted with respect to parameters such as girder spacing, skew angle, and deck aspect ratio. Although the slip at the interfaces between the concrete deck and steel girders results in the reduction of seismic total base shear in the transverse direction due to period elongation, it causes an undesirable behavior of skew bridges by the modification in mode shapes and distributions of stiffness. Shear connectors placed by minimum requirements for partial composite action have an effect on reducing the girder stresses and deck stresses; except case of some skew bridges, the magnitude of the girder stresses and deck stresses obtained from partial composite skew bridges is similar to or slightly more than those acquired from composite skew bridges.

• International conference on construction engineering and project management
• /
• 2013.01a
• /
• pp.608-615
• /
• 2013

The major countries including Korea extend the national investment on R&D and implement the business performance diffusion policy as the knowledge based competition age arrives recently. The necessity for risk management and systematic management system for R&D achievement have been appeared to prevent the failure as the R&D scale becomes larger as it was said. For this matter, the organization such as NASA and DoD in USA defines the Technology Readiness Level (TRL) as a quantitative accomplishment management index and utilize the Technology Readiness Assessment (TRA) system as a criterion. Such tool is evaluated as very effective in the R&D project purposed the practicalization. It is expected that the disadvantage of evaluation system which is oriented to the academic accomplishment in its contents of current research and to contribute greatly to the practicalization of outcomes when such technology readiness level concept is applied to Korean national construction and transportation R&D project. Accordingly, this study analyzed the concept of TRL·TRA, the characteristics and current evaluation management system of Korean national construction and transportation R&D project and suggested the construction and transportation R&D project TRL·TRA performance model to accomplish the practicalization purpose.

• Structural Engineering and Mechanics
• /
• v.45 no.5
• /
• pp.703-722
• /
• 2013

In this paper a study about concrete arch bridges built by lattice cantilevers is presented. Lattice cantilevers are partial structures composed of deck, arch, piers and provisional steel diagonals, organized as reticular cantilever girders, in order to build arch bridges without the use of centrings, supports or temporary towers. Characteristics of this construction methodology with its variants are explained together with their implications in the erection sequence. Partial elastic scheme method is implemented in order to find initial forces of temporary cables and a forward analysis is carried out to follow the actual sequence of construction, by extending a procedure already applied to concrete cable-stayed bridges and to arches built by the classical suspended cantilever method. A numerical application on a case-study of a concrete arch bridge is performed together with a comparison between different methodologies followed for its construction sequence. Differences between erection by lattice cantilevers and cable-stayed cantilevers, are discussed. Results can be useful for designers in conceptual design of concrete arch bridges.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2001.11a
• /
• pp.347-354
• /
• 2001

Extradosed PSC Box bridges, newly emerging type of structures in construction market, have a characteristic in that external tendons are used for strengthening PSC Box girder like stay cables in cable stayed bridges. In this study, a series of constructions stage analysis procedure, including initial shape analysis, backward analysis and forward analysis, have been performed in order to investigate long-term behavior of extradosed PSC box bridges, using PCCAP-a computer program for time-dependent stage analysis of PSC cable stayed bridges. CEB-FIP 1978 model was used for the consideration of time-dependent effect of concrete material. Showing the validity of the analysis results with RM SPACE FRAME, it has been confirmd that time-dependent effects become less consequential as the stiffness of girder becomes larger.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1996.10a
• /
• pp.520-525
• /
• 1996

Recently, the prestressed concrete long-span bridegs are increasingly built at various locations in the world. The mechanical and structural behavior of prestressed concrete bridges is very complex because of nonlinear and time-dependent material behavior and sequential change of structural system due to stepwise construction. These factors may cause construction errors with respect to design value and monitoring system is needed to minimize or to protect construction errors. This study presents the basis development of monitoring system for precise construction of large scale prestressed concrete bridges.

• Proceedings of the KSR Conference
• /
• 2007.05a
• /
• pp.1037-1043
• /
• 2007

The railroad systems with the ballast tracks have been widely used for a long time. But recently, the use of the slab track is being increased gradually with a technical developments. So, this paper deals with the appliance of the slab tracks on the railroad bridges. Firstly, review the design criteria of the railroad bridges related to the slab tracks for the stability and serviceability, based on DIN and EURO code. Then, perform the analysis of the railroad prestressed concrete bridges, and check whether the results of the analysis satisfy the design criteria. Finally, find the construction condition of bridges that all the design criteria are satisfied. As a result, to maintain the stability and serviceability of the bridges, bridges must have some restrictions, including a time of installation of the slab tracks. So, the construction schedule for the erection of the bridges will be carefully considered in case of the concrete railroad bridges with the slab tracks.

• Journal of Korean Society of Steel Construction
• /
• v.17 no.5 s.78
• /
• pp.511-518
• /
• 2005

The behavior of steel curved bridges is more complicated than straight bridges, thus the analysis, design and construction process of curved bridges require much more attention. In design of curved bridges, the grillage analysis using general structural analysis program or special program is mainly used. Comparative study in coherence between these analytical results and actual behavior of curved bridges has been rarely conducted. To study the behaviour of curved bridges and verify the current design method, field measurements and analyses using general structural analysis program and 3-D refined analysis program were carried out for simple and continuous bridges in this study. The study focused on the behavior of curved steel bridges during construction. Measured and analytical results had quantitative difference mutually, but there were qualitatively similar. Stress variations in transverse direction of flange were observed and grillage analysis models yielded more conservative values than 3-D refined analysis models.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.6 no.1
• /
• pp.131-140
• /
• 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.

• International conference on construction engineering and project management
• /
• 2009.05a
• /
• pp.1324-1327
• /
• 2009

Social infrastructure is the basis of public welfare and should be recognized and managed as important assets. Bridge is one of the most important infrastructures to be managed systematically because the impact of the failure is critical. It is essential to monitor the performance of bridges in order to manage them as an asset. But current analytical methods such as predictive modeling and structural analysis are very complicated and difficult to use in practice. To apply these methods, structural and material condition data collection should be performed in each element of bridge. But it is difficult to collect these detailed data in large numbers and various kinds of bridges. Therefore, it is necessary to collect data of major measurement items and predict the life of bridges roughly with advanced information technologies. When certain measurement items reach predefined limits in the monitoring bridges, precise performance measurement will be done by detailed site measurement. This paper describes the selection of major measurement items that can represent the tendency of bridge life and introduces automated bridge data collection test-bed using wireless sensor network technology. The following will be major parts of this paper: 1) Examining the features of conventional bridge management system and data collection method 2) Mileage concept as a bridge life indicator and measuring method of the indicator 3) Test-bed of automated and real-time based bridge life indicator monitoring system using wireless sensor network

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.29 no.3A
• /
• pp.181-188
• /
• 2009

This study presented the basic data for determining reasonable construction method and evaluating the structural safety of suspension bridges. The analytical program was developed to conduct initial shape and natural frequency analysis, construction stage analysis and reliability analysis considering construction sequences. This program was based on analysis models of suspension bridges and reliability theories used in the previous study. A construction method was established considering various construction variables such as construction order and construction direction of girder and synchronized construction of main and side span etc. The dynamic construction analysis by a construction scheme was conducted with the developed program. Benefits of the characteristic analysis by the construction scheme was presented estimating structural response of critical members respectively. Structural reliability analysis by construction stage was conducted considering aleatory uncertainties. The safety of suspension bridges by established construction method was quantitatively estimated using reliability index and failure probability. Analytical results were re-estimated considering epistemic uncertainties, and critical percentile distributions of risk at the construction stage were presented using the frequency histogram.