中文摘要：

结合交通生命线地震震害特点，对比国内外相关规范，探讨了我国公路桥梁的合理抗震设防理念。指出采用较高重要性修正系数的高等级公路不等同于线路整体具有较高的地震生存概率，合理的桥梁抗震设防标准除了要考虑路网等级、结构重要性等因素以外，还应结合当地防震减灾紧急通行计划来加以确定。“小震不坏、大震不倒、救灾生命线可通”的多级设防思想与桥梁结构的设防目标是一致的，在小震下的强度检算宜针对不同等级的桥梁采用不同的重要性修正系数以减少对经济正常运行的干扰，在大震下宜针对是否隶属于救灾紧急通行计划分别按照不倒塌或可通行的目标进行设防。分析了具有中、长基本周期的桥梁的地震反应特点，指出单纯采用场地设防基本烈度来区分其地震危险性的大小是不合理的，文中建议以基本烈度、特征周期和结构重要性修正系数的乘积，作为抗震构造措施等级选取的控制指标。

英文摘要：

Seismic fortification of highway bridges is discussed, based on an analysis of the damage characteristics of transportation lifelines under earthquake and comparison of seismic design codes of highway bridges both domestic and abroad. It is pointed out that a high-grade highway with higher coefficient of importance does not imply the whole road network has a higher seismic survival probability. Rational seismic fortification of bridges should take account of the local urgent transportation plan, in addition to the road grade and the structure itself. The idea of ＂no damage under frequent earthquake, no collapse under severe earthquake and keep transitable for the urgent transportation lifeline＂ is consistent with the fortification objective of bridges. Different correction coefficients of importance should be adopted for different bridge categories under frequent earthquakes in order to minimize the disturbance to normal operation. The objective of no collapse or transitability should be adopted under severe earthquakes depending on whether the bridge belongs to an urgent transportation plan. The seismic performance of bridges with moderate-to-long natural periods is analyzed, and the result shows it unreasonable to distinguish the potential seismic risk only by the basic earthquake intensity. A product of the basic earthquake intensity, the characteristic site period and the correction coefficient of importance is suggested as a control index for details of seismic measures.