摘要
为研究拉索损伤作用下双钢拱塔斜拉桥的动力特性和抗震性能,以西安市富裕路沣河大桥为工程背景,采用有限元软件MIDAS/Civil建立有限元三维模型,研究不同位置、不同数量的拉索断裂后对桥梁动力性能的影响,深入分析地震和断索同时作用时主梁线形、拉索索力、主梁及索塔应力的变化规律。结果表明:单索断裂对桥梁自振频率的降幅较小,最大仅为5.12%;外侧斜拉索或水平索断裂较内侧断裂对桥梁的动力特性影响大;双索断裂时桥梁自振频率和剩余拉索索力的变化值约为这2根拉索单独断裂时的变化值之和,基本符合叠加原理;地震作用下2根危险索同时断裂后,剩余拉索索力最大值已不满足规范《公路斜拉桥设计细则》(JTG D65-01—2007)中拉索安全系数不小于2.5的要求,应采取措施予以加强,或者可取计算应力小于0.28fpk(fpk为屈服强度),以确保安全系数在规范规定范围之内,从而保证桥梁结构安全;桥梁自振频率变化率与拉索损伤程度的变化基本呈线性关系;竖向地震作用对剩余拉索索力的影响要高于水平地震作用,断索对剩余拉索承载力的影响要高于对主梁和索塔的影响。该结论可为同类桥梁索系的设计和后期维护提供一定参考。
In order to study the dynamic characteristics and seismic performance of a double-steel arch tower cable-stayed bridge under the action of cable damage, Fenghe Bridge on Fuyu Road in Xi’an was used as an engineering background, and its three-dimensional FEM model was established by the software MIDAS/Civil. The influence of different positions and different numbers of cable breaks on the dynamic performance of the bridge were studied, and the changes in the line shape of the main beam, the cable force, the stress of the main beam and the tower were analysed when the earthquake and the broken cable act simultaneously. The results show that single-cable rupture reduces the natural frequency of the bridge very little, with the maximum value being only 5.12%. Outer stay cables or horizontal cable breaks have a greater impact on the dynamic characteristics of the bridge than the inner stay cables or horizontal cable breaks. The change value of the bridge natural frequency and the remaining cable force when the double cable breaks is approximately the sum of the corresponding changes when the two cables break separately, which is in line with the superposition principle. Under the action of an earthquake, when two dangerous cables break at the same time, the maximum remaining cable force does not meet the requirement that the cable safety factor is not less than 2.5 in the specification Design rules for highway cable-stayed bridges(JTG D65-01—2007), measures it should be taken to strengthen, or it is advisable to calculate the stress less than 0.28fpk to ensure that the safety factor is within the specified range of the code, thereby ensuring the safety of the bridge structure. The change rate of bridge natural frequency and the degree of cable corrosion damage are basically linear. The effect of vertical seismic action on the remaining cable force is higher than that of horizontal seismic action, and the impact of broken cables on the bearing capacity of the remaining cables is greater than the impact on the main beams and pylons. The conclusions obtained can provide a certain reference for the design and later maintenance of this type of bridge cable system. 4 tabs, 10 figs, 26 refs.
作者
黄华
白豪
周文杰
郭朋
杨坤
HUANG Hua;BAI Hao;ZHOU Wen-jie;GUO Peng;YANG Kun(School of Civil Engineering,Chang'an University,Xi'an 710061,Shaanxi,China)
出处
《长安大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2021年第2期114-124,共11页
Journal of Chang’an University(Natural Science Edition)
基金
国家自然科学基金项目(51778060,51708035)
陕西省重点研发计划项目(2020KW-067)
中央高校基本科研业务费专项资金项目(300102289401)。
关键词
桥梁工程
V形双钢拱塔斜拉桥
有限元模拟
拉索断裂
损伤机理
动力性能
bridge engineering
V-shaped double steel arch tower cable-stayed bridge
finite element simulation
cable fracture
damage mechanism
dynamic performance
