Effect of Vertical Earthquake Components on Bridge Responses

• Main Authors: Cheng-Fang Tsai, 蔡政芳
• Other Authors: CHIH-PENG YU
• Format: Others
• Language: zh-TW
• Published: 1999
• Online Access: http://ndltd.ncl.edu.tw/handle/40773494015899610400

碩士 === 朝陽大學 === 營建工程系碩士班 === 87 === The vertical components of the ground motion are rarely taken into account in the seismic design of regular buildings or highway bridges. It is commonly felt and widely accepted that vertical vibrations are much less important than the horizontal ones and that they can be neglected without impairing the safety of the structures. This is because vertical accelerations decay rapidly with distance and are normally smaller than the horizontal ones, unless one is close to the causative fault. On the other hand, for structures located in the epicentral region, the effect of the vertical acceleration component may not be negligible and may contribute to the premature failure of structures with a small margin of safety. This would be more so if the vertical component had a significant amount of energy in the high frequency range. In this work, the effect of the vertical component of motion on the seismic response of prestressed concrete bridge structures was evaluated. The study was carried out simulating one typical post tensioning highway bridge subjected to ground motions recorded during 1994 Northridge, 1995 Kobe and 1998 Ruili earthquakes. The effects examined are the vertical accelerations of the deck and the forces in the piers and girders.