• Journal of the Korea institute for structural maintenance and inspection
• /
• v.2 no.4
• /
• pp.137-147
• /
• 1998

The neural net application was tried to develop the technique for monitoring the health status of a steel truss bridge which was scaled down to 1/15 of the real bridge for the laboratory experiments. The damage scenarios were chosen as 7 cases. The dynamic behavior, which was changed due to the breakage of the members, of the bridge was investigated by finite element analysis. The bridge consists of single spam, and eight (8) main structural subsystems. The loading vehicle, which weighs as 100 kgf, was operated by the servo-motor controller. The accelerometers were bonded on the surface of 7 cross-beams to measure the dynamic behavior induced by the abnormal structural condition. Artificial neural network technique was used to determine the severity of the damage. At first, the neural net was learnt by the results of finite element analysis, and also, the maximum detection error was 3.65 percents. Another neural net was also learnt, and verified by the experimental results, and in this case, the maximum detection error was 1.05 percents. In future study, neural net is necessary to be learnt and verified by various data from the real bridge.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.4 no.2
• /
• pp.103-111
• /
• 2000

The objectives of the study are to know the strain distribution and modal dynamic behaviour of steel bridge girders by actual traffic load. The live load effect depends on many parameters including the span length, gross vehicle weight, axle weight, axle configuration so on. For the estimation of static and dynamic characteristic, strain data caused by moving loads and traffic characteristics of passing vehicle under actual traffic load have measured using Bridge Weigh in Motion. To confirm the reliability of BWIM system, strain data measured using the $120{\Omega}$ strain gauge under the same condition. It is considered that the data acquired from BWIM system have reliability through the analysis and comparison between stress measured by strain data from BWIM and computed by FEM. Additionally according to the measured strain data of up-line and down-line on the highway, the up-line bridge grows more faster than the down-line bridge and girder 4 and 5 carry more load when vehicles pass the inner line and girder 2 and 3 does when vehicles pass the outer line as this case(the bridge composed with 5 girders).

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.23 no.4
• /
• pp.53-60
• /
• 2019

In this study, a method for updating the finite element model of bridges with genetic algorithm using static displacement were presented, and verified this method using field test data for PSC girder bridge. As a field test, static load test and pseudo-static load test were conducted, and updated the finite element model of test bridge using each test data. Finally, evaluated the bridge load carrying capacity with updated model using pseudo-static load test's displacement data. To evaluate the bridge load carrying capacity, KHBDC-LSD, KHBDC and AASHTO LRFD's live load model were used, and compared the each results.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.7 no.2
• /
• pp.115-124
• /
• 2003

A prestressed concrete slab bridge is analyzed by the specially orthotropic laminates theory. Both the geometry and the material of the cross section of the slab are considered symmetrical with respect to the mid-surface so that the bending extension coupling stiffness, $B_{ij}=0$, and $D_{16}=D_{26}=0$. Each longitudinal and transverse steel layer is regarded as a lamina, and material constants of each lamina is calculated by the use of rule of mixture. This bridge with simple support is under uniformly distributed vertical and axial loads. In this paper, the finite difference method and the beam theory are used for analysis. The result of beam analysis is modified to obtain the solution of the plate analysis.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.4 no.4
• /
• pp.211-218
• /
• 2000

Many bridges are severely damaged by the overloaded heavy vehicle and the trend will become more serious because the traffic volume is continuously increasing. Currently, the vehicles with gross weights over 40 tonf or axle weight over 10 tonf are not allowed on the public road. However, this regulation is not based on a systematic study on the bridge capacity and assumed to be much too conservative depending on the vehicle types and bridge types. In this study, the permit weights of heavy vehicles of diverse axle spacings and axle load distribution are calculated considering the structural characteristics of bridge superstructures. In order to consider the various load effects of heavy weight vehicle crossings, three conditions are considered in the calculation of permit vehicle load. From the results, the permit vehicle weights of the simple girder bridges are calculated.

• Steel and Composite Structures
• /
• v.3 no.1
• /
• pp.13-32
• /
• 2003

In this paper design and fabrication information system for steel bridge construction is studied and proposed according to the progress of Construction CALS/EC in the construction industry in Japan. The data exchange in this system bases on the text file as well as CAD data with simplified drawings. The concept of this system is discussed following the analysis on the issues of the conventional system. The application of the product model is also discussed including effects and issues on the inspection system. This paper is based on the study carried out by Special Committee on Construction CALS of JASBC to which author belong.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.4 no.1
• /
• pp.131-138
• /
• 2000

In this study, physical and engineering properties of ordinary portland cement and microcement were investigated to verify reinforcing effect of underpinning of open caisson foundation by using microcement grouting. Laboratory injection tests such as infiltration and injection in case of seepage for the stream bed soil at ${\bigcirc}{\bigcirc}$ Great Bridge in Seoul were carried out. Field injection tests to reinforce open caisson foundation at ${\bigcirc}{\bigcirc}$ Great Bridge were performed and the ability of application by microcement grouting was evaluated. From the test results, physical and engineering properties of microcement are better than those of ordinary portland cement. Also, the ability of infiltration and solidity in case of seepage is better than that of ordinary portland cement. Therefore, it is concluded that microcement is an excellent material to reinforce open caisson foundation of the existing bridge structure under the water and can be used as underpinning material of general foundations.

• Magazine of the Korea Institute for Structural Maintenance and Inspection
• /
• v.18 no.1
• /
• pp.53-62
• /
• 2014

• Magazine of the Korea Institute for Structural Maintenance and Inspection
• /
• v.17 no.2
• /
• pp.29-35
• /
• 2013

• Magazine of the Korea Institute for Structural Maintenance and Inspection
• /
• v.17 no.2
• /
• pp.36-44
• /
• 2013