The purpose of this study is to analyse site natural period for estimating resonance of soil-structure. The natural period of seismic accelerometer installed site is calculated with HVSR(Horizontal to Vertical Spectral Ratio) proposed by Nakamura. To analyze natural period, a micro tremor is used at several sites. The result can be used for the study of soil-structure resonance, site classification and the site amplification effects.

Ground liquefaction of sandy ground during earthquake is a major problem that may cause big catastrophes to infrastructures. In seismic evaluation, it is important to describe correctly the mechanical behavior of soils subjected to cyclic loading in order to avoid or reduce the damages caused by liquefaction. However it needs a lot of time and efforts. Therefore in this study, we tried to evaluate the elaborate way for ground liquefaction hazard map using a simple method for estimating.

This study is about an earthquake disaster response system and an application technology for post-earthquake safety evaluation. The mobile application supports field survey on earthquake damage buildings and shortens the surveying time. The results from the mobile are transmitted to a data managing program. And it displays a surveyed-place, result and suggests statics. This system is expected to support local governments to effectively respond to earthquake disasters.

As the results of continual static and dynamic nonlinear analyses, it was found that the residual seismic capacity of RC partial frame was sharply diminished with the yielding of some reinforcements which correspond to the damage level of 2, but gradually diminished with expanding of damage over damage level of 3.

It is required that a compatible model be developed to properly control facility’s damage resulting from diverse natural and man-made disasters. The model is usually established by the results obtained from expert-oriented questionnaire surveys. This study carried out expert-oriented surveys in the field of facility’s disaster control and their results were analyzed using attractive and compatible indices. The survey results show that the applicability index of technologies for facility’s disaster control is the priority rather than other indices.

The natural period is generally used for monitoring the change in structural dynamic characteristics. It is legally obligated in Korea that seismic acceleration measurement system is installed in structures and measured data are transmitted. However there are some difficulties that the natural period is automatically analyzed by the structural acceleration analysis system. First, structural characteristics is changed by various factor such as plan shape, foundation type, structure type, size, and so on. Second, there are many factors ― machinery(basement), conditioning equipment(roof) ― causing noises near the measurement system installation point. Lastly, there are only sent some interval data by earthquake except ambient vibration to the analysis system. In this study to estimate the natural period, systemic approach is developed using simple evaluation formula from Korean Building Code-2009(KBC-2009).

Natural frequency changes of an in-service concrete bridge have been monitored to analyze the dynamic characteristic according to temperature and embedded depth changes. 7 acceleration sensors are attached to the bridge, and 11 time impact experiments have been done using the impact hammer. The natural frequency has a trend to drop as the surface temperature of the body goes up. And it also has a trend to decrease as the embedded depth of the bridge foundation increases.

This study analyzes damage estimation technique of earthquake disaster. In order to do this, 1) Proposition of current situation analysis and direction of improvement domestic and foreign-related systems of earthquake disaster response system, 2) Establishment and design of research earthquake disaster damage assesment system 3) Analysis and investigation of domestic and foreign-related soil field on damage estimation, 4) Creation of soil liquefaction risk-map and processes method of soil information. When occurred an earthquake, occurs the system rapidly displays seismic intensity distribution and life, structure, lifeline damage estimations. This enables decision makers to support the earthquake disaster response decisions. Eventually, earthquake disaster damages are expected to be reduced significantly.

A mobile application to support field survey on earthquake damage buildings and to shorten the surveying time. The results from the mobile are transmitted to a data managing program. And it displays a surveyed-place and result and suggests statics. This system is expected to support local governments to effectively responds to earthquake disaster.

Many researches about damage prediction for earthquake have been managed separately in Korea so that it would be managed comprehensively and systematically. Also it is necessary to develop the algorithms of ground for earthquake disaster response system in NEMA. This is a study to improve the reliability for damage estimation. We compared foreign cases to find a development direction which can be applied to the earthquake disaster response system.

To evaluate the shear strength of unreinforced masonry wall with/without a opening, analysis is conducted with/without a opening. As a result, the strength, stiffness, displacement are evaluated by using analysis program. Using this method, it is abel to evaluate the seismic performance of unreinforced masonry wall

Many researches about damage prediction for earthquake have been managed separately in Korea so that it would be managed comprehensively and systematically. Also it is necessary to develop the algorithms of ground for earthquake disaster response system in NEMA. This is a study to improve the reliability for damage estimation. We compared foreign cases to find a development direction which can be applied to the earthquake disaster response system.

This study suggests the operation plan of the seismic acceleration instrument installed in the domestic facilities and the using plan of the measured data through the provided data and the case study of the U.S.A and Japan

This study suggests a method for estimating embedded depth of a scoured bridge foundation using inverse analysis with natural frequency, that is a lot affected by soil stiffness around the structure. And applicability of the inverse analysis is performed by comparison of test results

10% drop of natural frequency from the initial healthy condition is reviewed to include the possibility of danger of foundation scour. To improve bridge safety management, legislations of measuring initial natural frequency, informing initial embedded depth, and systematic management of bridges under the control of the local governments are suggested.