Bridge Girder Design and Analysis: Earthquake and Movement

This project delves into the critical aspects of bridge girder design, focusing on the impact of earthquakes and the resulting movements. It explores the challenges posed by pounding damage in bridge girders, emphasizing the need for proper separation between adjacent structures to mitigate collision risks. The study investigates the influence of spatial ground excitation, soil-structure interaction (SSI), and the properties of modular expansion joints (MEJs) on bridge girder behavior. The research examines various factors inducing girder movement, including ground motion, uneven vibration properties, and soil variations. The project also analyzes the effects of the fundamental frequency ratio of adjacent structures and apparent wave velocity on the required MEJ gap to prevent pounding. The project's findings highlight the importance of considering a combination of SSI, spatial ground excitation variations, and the fundamental frequency ratio in the design of bridge girders to ensure structural integrity during seismic events. The project analyzes the influence of various factors on the relative movement of bridge girders, including the combined influence of SSI, spatial variation in ground excitation, and the ratio of fundamental frequencies in adjacent structures. The results indicate that the current design regulations, which avoid relative movement by developing structures with similar fundamental frequencies, may not be adequate. The project concludes that the minimum MEJ gap should not be related to a single influencing factor, as there is a combined influence that dominates. The project also emphasizes the importance of considering the apparent wave velocity and spatial variation in ground motion when designing MEJs to accommodate relative movements in bridge girders.