Kodai Matsuoka

NUMERICAL ANALYSIS FOR THE DYNAMIC RESPONSE CHARACTERISTICS OF THE PRESTRESSED CONCRETE SLEEPER

Abstract. The Prestressed concrete sleeper (PC sleeper) has many advantages over the wooden sleeper in terms of maintenance, load bending capacity, weight and lateral ballast resistance force. In Japan, the PC sleeper has been widely used since 1951. The PC sleeper is designed in consideration of the impact wheel load which is mainly caused by a rail joint or wheel flat. This research focused on the impact wheel load at rail joints. By field measurements in an operating line and numerical analyses, the dynamic response characteristic of the PC sleeper was clarified. The field measurement of PC sleeper behavior shows that the maximum bending moment of a PC sleeper with a rail joint during train running is almost 4 times larger than that in plain sections, and the maximum bending moment of the PC sleeper adjacent to the rail joint is almost 2.7 times larger than that in plain sections. The numerical analysis shows that support condition has the greatest influence on the bending moment of the PC sleeper among various parameters. Furthermore, the impact wheel load caused by a rail joint affects dynamic behavior of PC sleepers within 4m from the rail joint.

Bridge Vibration Monitoring using Passing Train Loads

In order to appropriately conduct maintenance of railway bridges with progressed deterioration, 1) Understanding the actual behavior of bridges under the passing train loads, and 2) Identifying vibration characteristics such as natural frequency, damping ratio and vibration mode shapes, are extremely important issues. In this paper, focusing on open deck bridges, a vibration monitoring method using the passing train loads is proposed. In order to verify the effectiveness of the proposed method, vibration measurement tests were carried out on an actual bridge and vibration characteristics were identified. Furthermore, by quantitatively evaluating the contribution rate of each mode component of actual behavior, the difference from the response characteristics of a general impulse hammer impact is clarified, and the significance of vibration monitoring using the passing train loads is discussed.