| Summary: | 碩士 === 國立臺北科技大學 === 土木與防災研究所 === 93 === There have been many examples of bridge failure caused by relative movement of spans in the longitudinal or the transverse directions exceeding the seating widths, and resulting in unseating at unrestrained movement joints in Northridge Earthquake (1994, U.S.A.), Kobi Earthquake (1995, Japan) and Ji Ji Earthquake (1999, Taiwan). This has been a particular problem for simply supported span bridges with tall columns. Restrainers may be placed across the joint in an attempt to reduce the relative displacements, or the displacement capacity of the movement joint can be increased. Restrainers are used to restrain displacement between the expansion joint, restrainers may be placed in order that longitudinal seismic force can be transferred between adjacent frames. The analysis and design for the interaction of inelastic frames connected by restrainers are complex and cannot be achieved by simple elastic analyses. Results from dynamic inelastic analysis incorporating relatively sophisticated modeling of the movement joints indicate that maximum longitudinal displacements can be estimated. Determination of the appropriate strength for the restrainers and reduction in displacement caused by stiff restrainers are difficult unless dynamic inelastic analyses are carried out. In many bridges the appropriate treatment for movement joints will be to use restrainers to lock the movement joints so that essentially no relative movement can occur.
In Japan, the design of restrainers and other earthquake resistance devices have been very well developed. In the States, the restrainers are mostly used in the existing bridges which are seismic deficiency. In Taiwan, the seismic design code of bridge follows the AASHTO bridge desingn code, and some of the earthquake devices and restrainers are supported by Japan. Therefore, we wuld like to developed the design and analysis methodology or guideline of the restrainers for the usage in Taiwan. The ANSYS finite-element softwares will be used in this project to simulate the force in the restrainer under earthquakes.
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