The occurrence of excessive fluid sloshing during an earthquake can damage structures used to store fluids and can induce secondary disasters, such as environmental destruction and human casualties, due to discharge of the stored fluids. Thus, to prevent such disasters, it is important to accurately predict the sloshing behavior of liquid storage tanks. Tubular level gauges, which visually show the fluid level of a liquid storage tank, are easy to install and economical compared to other water level gauges. They directly show the fluid level and can be applied for various fluids because they can be constructed with various materials according to the fluid characteristics and the intended use. Therefore, in this study, the shaking table test was conducted to verify the validity of the method for measuring the water level response of the tubular level gauge installed on a liquid storage tank using image signals. In addition, image enhancement methods were applied to distinguish between the float installed in the tubular level gauge and the gray level of the background.

In this study, a shaking table test was performed to analyze the anchor behavior with or without rocking in the base plate of an electric cabinet. Two cabinets, differentiated by whether their base plates were anchored or fixed, were mounted simultaneously on a shaking table to enable a comparison of their behavior when subjected to seismic motion. Three seismic waves were used in this experiment to facilitate temporal history and resonance search. Results indicated that the impact load occurred due to mutual collision with the local mode of the cabinets’ internal components. Moreover, in the case of a single-door cabinet with a bolt fastening, it was observed that rocking mode occurred due to upliftment of the base plate. To address this problem the cabinet was tested again after being reinforced and the results achieved before and after the reinforcement procedure were discussed.

The interest in the seismic performance of nuclear power plants has increased worldwide since the Fukushima Daiichi Nuclear Power Plant incident. In Korea, interest in the seismic safety of nuclear power plants has increased since the earthquake events in Gyeongju (2016) and Pohang (2017). In Korea, studies have been conducted to apply seismic isolation systems to ensure seismic safety while minimizing the design changes to nuclear power plants. Nuclear power plants with seismic isolation systems may have a higher seismic risk due to the failure of the piping system in the structure after a relatively large displacement. Therefore, it is essential to secure the seismic safety of pipes for the safe operation of nuclear power plants. The seismic safety of pipes is determined by seismic fragility analysis. Seismic fragility analysis requires many seismic response analyses because it is a statistical approach to various random variables. Typical numerical conditions affecting the seismic response analysis of pipes are the convergence conditions and mesh size in numerical analysis. This study examined the change in the seismic safety of piping according to the numerical conditions. The difference in the seismic response analysis results of the piping according to the mesh size was analyzed comparatively. In addition, the change in the seismic fragility curve of the piping according to the convergence conditions was investigated.

Among national infrastructure facilities, electric power facilities are very important sites that must maintain their functions properly even during a natural disaster or during social crises. Therefore, seismic design is required when necessary for major electric power facilities that have a significant impact when damaged in the event of an earthquake. In electric power facilities, bushings are generally installed in devices or structures. Therefore, ground acceleration can be amplified through devices, such as transformers, or sub-structures. Among various electric power facilities, cable terminations are representative cantilever-type substation facilities consisting of a bushing, a sub-structure, and support insulators. The bushings of cable terminations are generally made of porcelain or fiber-reinforced plastic (FRP) materials, and they may have different dynamic characteristics. This study attempted to estimate the acceleration amplification ratio in the main positions of cable terminations considering the materials of bushings. For two cable terminations with different specifications and bushing materials, three-axis shake table tests were conducted in accordance with IEEE 693, which includes a seismic performance evaluation method for a power substation facility. The acceleration amplification ratios at the top of the bushing, mass center, and top of the support structure were estimated using the acceleration responses of each cable termination. They were then compared with the acceleration amplification factors presented in design standards. Consequently, the acceleration amplification ratio of cable termination with an FRP bushing was lower than that of the cable termination with a porcelain bushing.