• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.26 no.6A
• /
• pp.977-988
• /
• 2006

The goal of this study is to develop a realistic methodology for determination of the Life-Cycle Cost (LCC)-effective optimal seismic retrofit and maintenance strategy of deteriorating bridges. The proposed methodology is based on the concept of minimum LCC which is expressed as the sum of present value of seismic retrofit costs, expected maintenance costs, and expected economic losses with the constraints such as design requirements and acceptable risk of death. The proposed methodology is applied to the LCC-effective optimal seismic retrofit and maintenance strategy of a steel bridge considered as a example bridge in the accompanying study, and various conditions such as corrosion environments and Average Daily Traffic Volumes (ADTVs) are considered to investigate the effects on total expected LCC. In addition, to verify the validity of the developed methodology, the results are compared with the existing methodology. From the numerical investigation, it may be positively expected that the proposed methodology can be effectively utilized as a practical tool for the decision-making of LCC-effective optimal seismic retrofit and maintenance strategy of deteriorating bridges.

• Smart Structures and Systems
• /
• v.21 no.2
• /
• pp.171-185
• /
• 2018

Maintenance of deteriorated bridge structures has always been one of the challenging issues in developing countries as it is directly related to daily life of people including trade and economy. An effective maintenance strategy is highly dependent on timely inspections on the bridge health condition. This study is intended to investigate an approach for detecting bridge damage for the long-term health monitoring by use of copula theory. Long-term measured data for the seven-span plate-Gerber bridge is investigated. Autoregressive time series models constructed for the observed accelerations taken from the bridge are utilized for the computation of damage indicator for the bridge. The copula model is used to analyze the statistical changes associated with the modal parameters. The changes in the modal parameters with the time are identified by the copula statistical properties. Applicability of the proposed method is also discussed based on a comparison study among other approaches.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.22 no.3
• /
• pp.36-43
• /
• 2021

Because bridges are major national infrastructure, regular safety inspections or diagnoses for bridges have been conducted in accordance with the "Special Act on the Safety and Maintenance of Facilities." Accordingly, the condition and safety assessments of the bridge are conducted to derive the condition and safety rating, respectively. A lower result is determined to be the safety grade of the bridge. In this study, the relationship between the condition rating and safety rating, which are the core of the bridge safety grade, was analyzed by the representative superstructure types of bridges, such as RC slab, PSCI girder, Steel box girder, Rhamen, and Preflex girder, to identify the correlation status and range between each rating. A reasonable improvement direction for establishing existing maintenance policies was suggested by proposing an alternative plan to change the proper implementation cycle of the inspection and diagnosis of bridge superstructure types. As a result of the research, it is necessary to adjust the inspection and diagnosis cycle according to the superstructure type and safety grade. In addition, maintenance policies need to be improved through detailed research on more diverse bridge types in the future.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2009.05a
• /
• pp.277-278
• /
• 2009

The building that supply tidal and splash zone was constructed near Seamangeum Gate Bridge. The specimens that will be tested for maintenance of gate bridge were exposed on the tidal and splash zone, totally about 650(Fig. 1). The characteristics of strength, salt penetration profile, field application of surface repair material and section recover material will be acquired by periodical test. The program was developed to obtain optimal maintenance strategy of gate bridge as a marine concrete structure and to deposit experimental data, lab. test result, field test result, on its D/B. On this paper, we hope to introduce two years exposure data as compressive strength, the modulus of elasticity, the modulus of dynamic elasticity, field adoption of repair and recover materials. As briefly speaking the results, possion's ratio, elasticity, strength was general, but the recover materials have some problems. There was crack between concrete and recover material and delamination figures.

• Korean Journal of Computational Design and Engineering
• /
• v.11 no.3
• /
• pp.183-196
• /
• 2006

A new operation strategy. which can guarantee the data consistency of engineering information among the various intelligent information systems, is presented for engineering information of bridges, and construction methodology of integrated database is developed to support the strategy. The two core standard techniques are adopted to construct the integrated database. One is the Standard for the Exchange of Product Model Data (STEP) for CAD/CAE information and the other is the Extensible Markup Language(XML) for engineering document information. The former enabler structural engineers to handle the structural details with three-dimensional geometry-based information of bridges, and ACIS solid modeling kernel is employed to develop AutoCAD based application modules. The latter can make document files into data type for web-based application modules which assist end-users to search and retrieve engineering document data. In addition, relaying algorithm is developed to integrate the two different information, e.g. CAD/CAE information and engineering document information. The pilot application modules are also developed, and a case study subjected to the Han-Nam bridge is presented at the end of the paper to illustrate the use of the developed application modules.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2006.04a
• /
• pp.208-215
• /
• 2006

This study provides a new operation strategy which can guarantee the data consistency of engineering information among the various intelligent information systems. We present the strategies for the operation of bridges engineering information and the construction methodology of integrated database. The two core standard techniques are adopted to construct the integrated database. One of these standards is the Standard for the Exchange of Product Model Data (STEP) for CAD/CAE information and the other is the Extensible Markup Language (XML) for engineering document information. This study can transform a document me into a data type for web-based application modules which assist end-users in searching and retrieval of engineering document data. In addition, relaying algorithm is developed to integrate the two different information, e.g. CAD/CAE information and engineering document information. The pilot application modules for management and maintenance of existing bridge are also developed to show application of the strategy.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.20 no.5
• /
• pp.50-57
• /
• 2016

The present study proposed three inspection reliability indices which compared inspection results evaluated at in-depth(routine) inspection and in-depth safety inspection; Nominal inspection reliability index, Real inspection reliability index, and DS nominal inspection reliability index. The methods to improve the inspection reliability were also proposed. Since bridge inspection process is critical to ensuring the safety of bridges and identifying repair and maintenance needs, the quality of the inspection data produced from the inspection process is very important. Consequently, the inspection reliability indices were suggested to evaluate quality of current inspection practices. Specifically, approximately 85% of inspection errors evaluated by the DS nominal inspection reliability index are within 1 rating grade(equal to or less than damage score ${\pm}0.1$). In order to improve the inspection reliability, transportation agency should implement QC(Quality Control) practices and develop professional expertises of inspectors by higher requirements for inspectors, on-off line inspection training and etc.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.11
• /
• pp.7893-7901
• /
• 2015

It is important to the periodic collection and analysis of the maintenance and management information of bridges for a more safe and efficient management of the bridges. To enhance the reliability and ease of acquisition of the bridge inspection information that is the basis for a strategy for safe and economic management using the bridge management system (BMS), this study develops a smart phone application for bridge inspection and ensures the actual applicability of the application. The developed application that is linked with the BMS for life-cycle management of bridges is possible to real-time query, modify and transmit of the maintenance-related information, and the application is able to greatly relieve the time and cost for the bridge inspection through the automatic creation of site inspection reports. The proposed method using the application is directly or indirectly expected to be very high effects of value improvement, such as ease of use, improved accuracy, sustainability of information, and future utilization, compared to conventional inspection method.

• Structural Engineering and Mechanics
• /
• v.85 no.4
• /
• pp.531-543
• /
• 2023

The existing concrete bridges are time-varying working systems, where the maintenance strategy should be planned according to the time-varying performance of the bridge. This work proposes a time-dependent residual capacity assessment procedure, which considers the non-stationary bridge load effects under growing traffic and non-stationary structural deterioration owing to material degradations. Lifetime bridge load effects under traffic growth are predicated by the non-stationary peaks-over-threshold (POT) method using time-dependent generalized Pareto distribution (GPD) models. The non-stationary structural resistance owing to material degradation is modeled by incorporating the Gamma deterioration process and field inspection data. A three-span continuous box-girder bridge is illustrated as an example to demonstrate the application of the proposed procedure, and the time-varying reliability indexes of the bridge girder are calculated. The accuracy of the proposed non-stationary POT method is verified through numerical examples, where the shape parameter of the time-varying GPD model is constant but the threshold and scale parameters are polynomial functions increasing with time. The case study illustrates that the residual flexural capacities show a degradation trend from a slow decrease to an accelerated decrease under traffic growth and material degradation. The reliability index for the mid-span cross-section reduces from 4.91 to 4.55 after being in service for 100 years, and the value is from 4.96 to 4.75 for the mid-support cross-section. The studied bridge shows no safety risk under traffic growth and structural deterioration owing to its high design safety reserve. However, applying the proposed numerical approach to analyze the degradation of residual bearing capacity for bridge structures with low safety reserves is of great significance for management and maintenance.

• Journal of Korean Society of Steel Construction
• /
• v.18 no.6
• /
• pp.677-686
• /
• 2006

In this paper, a more practical and realistic method is proposed to establish the lifetime optimum maintenance strategies of the deteriorating bridges considering the life-cycle performance as well as life-cycle cost. The genetic algorithm is applied to generate the set of maintenance scenarios that is the multi-objective combinatorial optimization problem related to lifetime performance and cost as separate objective functions, and the technique to select optimum tradeoff maintenance scenario is presented. Optimum maintenance scenarios could be generated not only at the individual member level but also at the system level of the bridge. Through the analytical results of applying the proposed methodology to the existing bridge, it is expected that the methodology will be effectively used to determine the optimum maintenance strategy for introducing a real preventive maintenance system and overcoming the limits of existing maintenance methods.