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.

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.

Kappa represents decay parameter about 3~4km under seismic stations. This study estimated domestic kappa characteristics. The korean peninsula kappa showed high value in gyeongsang basin be known as sedimentary rock local as a result of this study.

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 proposed immediate estimation method for structural integrity using acceleration responses after earthquake. Generally, structural damage detection searching for changes in the natural frequencies by acceleration data. However structure’s natural frequency is changed without damage because of various environmental factors. So that reason, we suggested structural safety estimation procedure using various indicators from analyzing acceleration data. This method is not exactly evaluated structural damage, but using this method is simple to make a decision.

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 proposed simplified design procedure of friction damper for enhancing structural seismic performance. Friction damper has a nonlinear characteristic as performing stick and slip motion. So that reason, design of friction damper is difficult. For easy design of damper, first, equivalent damping ratio of the friction damper is derived. Second, design procedure is proposed by the equivalent damping ratio. Finally, seismic performance of structure installed with the friction damper is verified by five earthquake data.

The purpose of this study is to consider site effect in order to estimate Soil-Structure and attenuation parameters with a greater degree of reliability. Site amplification is calculated by proposed Nakamura (H/V ratio). The site amplifications using acceleration motion were compared at several sites. The result can be used for the study of site classification and removal of the site amplification effects.

In this study the evaluation of technologies for standardization in foundation structures are done. For this, reliablity-based methods of investiugation data analysis are suggested in this paper.