• Structural Engineering and Mechanics
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• v.43 no.1
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• pp.127-145
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• 2012

One of the most important and challenging steps in seismic vulnerability and performance assessment of highway bridges is the determination of the bridge component damage parameters and their corresponding limit states. These parameters are very essential for defining bridge damage state as well as determining the performance of highway bridges under a seismic event. Therefore, realistic damage limit states are required in the development of reliable fragility curves, which are employed in the seismic risk assessment packages for mitigation purposes. In this article, qualitative damage assessment criteria for ordinary highway bridges are taken into account considering the critical bridge components in terms of proper engineering demand parameters (EDPs). Seismic damage of bridges is strongly related to the deformation of bridge components as well as member internal forces imposed due to seismic actions. A simple approach is proposed for determining the acceptance criteria and damage limit states for use in seismic performance and vulnerability assessment of ordinary highway bridges in Turkey constructed after the 1990s. Physical damage of bridge components is represented by three damage limit states: serviceability, damage control, and collapse prevention. Inelastic deformation and shear force demand of the bent components (column and cap beam), and superstructure displacement are the most common causes for the seismic damage of the highway bridges. Each damage limit state is quantified with respect to the EDPs: i.e. curvature and shear force demand of RC bent components and superstructure relative displacement.

• Structural Engineering and Mechanics
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• v.91 no.1
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• pp.25-38
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• 2024

After the mainshock, whether the train can be allowed to pass the bridges plays an important role in ensuring the transport of supplies and rescue works for example, in the "12 May" earthquake in China, after evaluation, the bridge was still used for transportation in rescue at a very slow speed, engineers usually evaluate whether the train can pass the bridge safely based on the experience, lacks sufficient calculation basis and does not fully consider the risk caused by aftershocks. To address this issue, this paper comprehensively considers the randomness of track irregularity, the randomness of aftershock intensity and other multiple random sources in train-bridge interaction system (TBIS). The sensitivity of train to various random parameters after earthquake is analyzed from the perspective of probability, the most sensitive random variable in this paper is PGA of aftershocks, both for bridge and trailer car, With the increase of epicentral distance, the sensitivity of PGA will decrease, and correspondingly, for trailer car, the sensitivity of other random variables will increase, research in this paper provides a basis for the subsequent random analysis of post-earthquake driving safety.

• Journal of Korean Society of Disaster and Security
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• v.16 no.2
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• pp.33-47
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• 2023

Under the "Act on Safety Control of Small Public Facilities (enacted in 2015)", each local government selects and conducts annual safety inspections for small public facilities. Among small public facilities, small bridges pose high risks and are heavily utilized by local residents, making them challenging to manage due to their large numbers and limited resources. Therefore, there is a need for a rational selection method that considers the management capacity of local governments, as well as the establishment of objective risk evaluation and maintenance planning for small hazardous facilities. In this study, we propose a selection method based on structural and functional classification of small bridges, considering the management capacity of local governments. Additionally, we present quantitative evaluation indicators for ten risk evaluation criteria, aiming to facilitate objective risk evaluation.

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.629-632
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• 2008

Risk-based security impact evaluation may be affected by various factors according to numerous combinations of explosive devices, cutting devices, impact vehicles, and specific attack location to consider. Presently, in planning and design phases, designers are still often uncertain of their responsibility, lack of information and training of security. Therefore, designers are still failing to exploit the potential to reduce threats on site. In this study, the concept of security impact assessment is introduced in order to derive the performing design for safety in design phase. For this purpose, a framework for security impact assessment model using risk-based approach for bridge structures is suggested. The suggested model includes of information survey, classification of terror threats, and quantitative estimation of severity and occurrence.

• Structural Engineering and Mechanics
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• v.85 no.4
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• pp.531-543
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• 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 the Korea Academia-Industrial cooperation Society
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• v.19 no.7
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• pp.88-94
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• 2018

This study examined the safety of a cable stayed bridge caused by damage to the cable system. Many cable-supported bridges, including cable-stayed bridges and suspension bridges, have been constructed on the Korean peninsula. This requires efficient maintenance and management because this structure has complex structural components and systems. This large structure also often faces risks either from manmade causes or natural phenomena. In 2015, the cables on one cable-stayed bridge in South Korea was struck by lightning, which led to a fire on the cables. These cables were damaged, which put the bridge at risk. This bridge was back in use after a few weeks of investigations and replacements of the cables but this was done at enormous social and economic expense. After this event, risk-based management for infrastructure is required by public demand. Therefore, this study examined the risks on the cable system due to potential damage. In this paper, a one cable-stayed bridge in South Korea was selected and its safety was investigated based on the damage scenarios of cable system for efficient and prompt management, and to support decision making. FEM analysis was conducted to evaluate the safety of the bridges after damage to the cable system.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.135-140
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• 2002

Bridge columns in strong earthquake area are to be designed and constructed so that enough ductility should be guaranteed. Therefore, large amount of transverse reinforcement is required to confine core concrete of the bridge column by design specifications. In moderate seismicity regions, however, adopting the full ductility design concept sometimes results in construction problems due to reinforcement congestion. For the moderate seismicity regions, a design based on required ductility and required transverse reinforcement might be a reasonable approach. Ductility demand design or performance-based design might be an appropriate approach especially for regions of moderate seismic risk. The procedure and application of this design approach are presented in this paper.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2011.11a
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• pp.13-15
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• 2011

This report represents analysis of the maritime casualty in terms of Bridge Resource Management. We evaluate the attitudes and knowledge of bridge officer regarding human factors issues that have been identified as causal to mishaps in high-risk situations. So to reduce human errors our goal is to establish effective officer resource management (ORM) program which is based on all subjects for cadets in IMO model course. In harmonization with STCW(The International Convention on Standards of training, Certification and Watch-keeping for Seafarers), as the result, the curriculumss in the maritime education institutions is surveyed to improve our education system and then reduce the human errors by mariners at sea.

• Journal of the Korean Society of Marine Environment & Safety
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• v.5 no.1
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• pp.1-8
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• 1999

During the last 10 years, the various type of high speed craft have been greatly developed, and since around of 1990 the large size of high speed passenger and/or cargo vessels are also introduced and took into the service in the various routes over the world. In a marine traffic way some bridge need to build across a rivers, cannals or a waterways. This one will be an obstruction and potential risk of collision in the way of high speed craft. Accordingly some of collision accident have been reported, which were caused by a lost control, wind and hydrodynamic forces, fog or human errors. In this paper a high speed craft having 40 m length is assumed to be collided with a circular type of bridge piers at right angle. The mode of deformation, penetration depth of collapse, impact forces, reduction of speed, loss of kinetic energy, and influence of scantlings, etc. have been calculated in each speed with a time variation to find a maximum values within a limit, and are graphically presented.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2001.09a
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• pp.311-319
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• 2001

Recently, the number of seismically isolated bridges increased suddenly since the occurrence of strong earthquakes. However, because isolator lies between pier and girder, the response of the superstructure of seismically isolated bridge may be magnified and induce risk of unseating girder Consequently, the response of girder constitutes a crucial factor in designing bridge. In the case of frictional bearing, the inherent nonlinearity makes the use of former linear response spectrum unable to estimate the maximum response of the bearing, and nonlinear tlme history analysis shall be applied. In this paper, nonlinear response spectrum considering frictional element is established, and simple analysis method using such nonlinear spectrum is proposed to estimate the maximum response of the superstructure.