【摘要】 为合理确定跨航道桥梁的船撞风险与防船撞设计水准，采用基于目标失效概率的分析方法，对某跨航道桥梁进行了船撞安全风险评估。根据美国AASHTO船撞分析规范推荐的船舶速度调整模型，对船舶碰撞速度进行了修正，并采用AASHTO经验数学模型进行了桥梁船撞概率计算。根据中国《公路桥梁抗撞设计规范》（JTG/T 3360-02—2020）中提供的等效静力法，计算了不同载重吨位与不同速度的船舶碰撞力。采用截面抗力法计算了桥梁的船撞抗力。通过对比桥梁船撞抗力与不同吨位级别的船舶碰撞力，分析得到了桥梁实际防撞水准，并根据桥梁目标失效概率(1×10^-4次/a)反推得到了桥梁设计防撞水准。结果表明：桥梁船撞安全风险主要来源于靠近航道下行线且船撞抗力较低的桥墩；桥梁在5 a和10 a后的船撞概率分别增长1.4倍和1.8倍，而桥梁的失效概率分别增长1.8倍和2.4倍，船舶流量增长过程中大吨位船舶比例增加，桥梁船撞失效概率的增长速率要高于船撞概率；采用基于目标失效概率得到的桥梁设计防撞水准可确保全桥各涉水桥墩具有相对一致的船撞安全可靠度，船撞失效风险处于可控水平，采用设计防撞水准后可使桥梁的船撞年失效概率较实际设防水准在目前及远期分别下降17.0倍和14.6倍。更多还原

【Abstract】 In order to reasonably determine the vessel collision risk and design fortification criterion against vessel collision for bridges cross navigable waterways, the risk assessment of a selected cross-channel bridge is conducted by using the analysis method based on target failure probability. According to the vessel speed adjustment model recommended by AASHTO vessel collision analysis specification, the collision speed of vessel is modified, and the bridge-vessel collision probability is calculated by using the AASHTO empirical mathematical model. According to the equivalent static method provided by Chinese Specifications for Collision Design of Highway Bridges（JTG/T 3360-02—2020）, the vessel collision forces under different load tonnages and different speeds are calculated. The collision resistance of the bridge is calculated by using sectional resistance method. The actual fortification criterion against vessel collision is obtained by the comparison between the bridge anti-collision resistance and vessel collision load at each tonnage level. The fortification criterion for bridge against vessel collision is inversely calculated based on the of bridge target failure probability(1×10^-4 times/a). The result shows that（1） Bridge-vessel collision risk mainly comes from the piers close to the down-bound line of the waterway with low structural anti-collision resistance.（2） The bridge-vessel collision probability after 5 years and 10 years increases by 1.4 times and 1.8 times respectively, while the failure probability of the bridge increases by 1.8 times and 2.4 times respectively. Since the proportion of large-tonnage vessels increases with the growth of vessel traffic, the failure probability of bridge increases at a higher rate than that of bridge-vessel collision probability.（3） The adoption of the designed bridge fortification criterion against vessel collision could ensure relatively uniform safety reliability for all in-water piers within overall bridge, and the failure risk of bridge due to vessel collision is at a controlled level. After adopting the designed anti-collision fortification criterion, the annual failure probability of the bridge due to vessel collision could be reduced by 17.0 times and 14.6 times respectively at present and in the future compared with the adoption of actual fortification criterion.更多还原