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Study on Fretting Fatigue of Prestressing Cable at, Deviator

偏向器预应力索微动疲劳研究

基本信息

批准号：
10555145
负责人：
KAKUTA Yoshio
金额：
$ 3.65万
依托单位：
HOKKAIDO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

项目摘要

The followings are summary of what have been obtained in this research.・ Fatigue strength of prestressing strand under effect of fretting is apparently smaller than that under ordinary fatigue loading.・ Fretting fatigue strength is influenced by stress range, slip range and contacting force. The greater stress range is, and the greater contacting force is, the smaller becomes the fatigue strength. The experimental fact indicates that how slip range influences fretting fatigue strength may depend on magnitude of slip range. Extent of influence of stress range and slip range is greater than that of contacting force.・ It is necessary to consider effect of slip range in the direction normal to strand axis besides that in the direction of the strand axis.・ Fretting fatigue occurs at contacting point between strands rather than between wires in the same strand. This fact indicates that there is the effect of slip range.・ Although contacting force is considered greater at inner contacting points than at outer one at deviator, location of fretting fatigue fracture was found almost evenly. This fact indicates either that with magnitude of contacting force observed in the experiment fretting fatigue strength is hardly affected by change in contacting force, or that actual contacting force in the experiment did not change by the location.・ Grouting in protection tube for cable and resin coating of strand can increase fretting fatigue strength, However, it is difficult to prevent fretting fatigue fracture by providing them only.・ Restriction of grout movement by taper inside protection tube or spacer of strand for reduction of contacting can prevent fretting fatigue fracture.

以下是本研究所得的总结。·微动作用下预应力钢索的疲劳强度明显小于普通疲劳载荷作用下的疲劳强度。·微动疲劳强度受应力范围、滑移范围和接触力的影响。应力范围越大，接触力越大，疲劳强度越小。实验结果表明，滑移范围对微动疲劳强度的影响可能取决于滑移范围的大小。应力范围和滑移范围的影响程度大于接触力的影响程度。·除了线轴方向的滑移范围外，还需要考虑线轴垂直方向的滑移范围的影响。微动疲劳发生在线与线之间的接触点，而不是同一股线之间的接触点。这表明存在滑移范围的影响。·虽然认为在偏差处内接触点的接触力大于外接触点，但微动疲劳断裂的位置几乎是均匀的。这说明在实验中观察到的接触力的大小下，微动疲劳强度几乎不受接触力变化的影响，或者实验中实际接触力不受位置的影响。·电缆保护管注浆和钢绞线树脂涂层可以提高微动疲劳强度，但仅提供这些很难防止微动疲劳断裂。·通过保护管内锥形或钢绞线垫片限制浆液运动，减少接触，防止微动疲劳断裂。