某T型刚构桥运营期健康状态分析
发布时间：2019-06-18 08:08
【摘要】：T型刚构桥在上世纪后半段一经问世,便得到了广泛应用。随着运营时间的增长和车辆荷载的长期作用,T型刚构桥容易出现下挠、位移等病害,影响桥梁结构的安全使用。依据桥梁定期检查和长期监测数据,对运营期T型刚构的健康状态进行评估研究,分析桥梁结构损伤程度,评价桥梁承载能力和安全度,为桥梁的养护和加固维修提供依据,具有一定的理论和和实际工程意义。本文依托广东某T型刚构桥长期变形监测和定期检测工程,应用MIDAS CIVIL软件进行有限元建模分析计算,结合桥梁定期检测、长期变形监测和静载试验,对运营期桥梁的健康状态进行了分析,结果表明:(1)桥梁悬臂端下挠与挂梁横向位移两种病害突出,悬臂端下挠的主要影响因素有混凝土收缩徐变、预应力损失和温度效应等,挂梁横向位移的可能影响因素有牛腿不对称下挠、支座脱空和横向荷载作用;(2)混凝土收缩徐变对桥梁挠度的影响与时间有关,下挠病害主要发生在成桥后一年内,随后逐渐趋于平稳;预应力损失工况下下挠量与预应力损失的系数大致呈线性相关;升温作用会在边跨部位轻微加大桥梁的下挠,在主跨部位使桥梁产生大幅的上拱以平衡下挠病害,降温作用反之亦然;(3)牛腿的不对称下挠对挂梁横向位移并不明显;支座脱空会加大横向位移,支座脱空一处的影响大于两处支座脱空;风速越大造成的桥梁横向位移越大,但从外侧而来的风对却边跨挂梁外移的病害有利;(4)该桥已安全运营20年,自2007年以来,桥面挠度变化较小,线形平顺;定期检测结果表明存在伸缩缝积砂土、支座轻微脱空、梁体和桥墩混凝土剥落、露筋锈蚀等病害;静载试验结果表明目前结构性能均满足设计要求。本文的分析证明了主桥的挠度变化和挂梁的横向位移均为多种因素共同作用的结果,虽然监测显示桥梁自加固以来桥梁挠度变化和横向位移变化均不大,且受力状态良好,但仍需继续对桥梁进行长期健康监测与定期检查,及时发现和预测结构病害,确保桥梁安全运营。
[Abstract]:T-shaped rigid frame bridge has been widely used as soon as it came out in the second half of the last century. With the increase of operation time and the long-term effect of vehicle load, T-shaped rigid frame bridge is prone to deflection, displacement and other diseases, which affects the safe use of bridge structure. According to the regular inspection and long-term monitoring data of the bridge, the health state of the T-shaped rigid frame during operation is evaluated and studied, and the damage degree of the bridge structure is analyzed, and the bearing capacity and safety degree of the bridge are evaluated, which provides the basis for the maintenance and reinforcement of the bridge, and has certain theoretical and practical engineering significance. In this paper, based on the long-term deformation monitoring and regular detection project of a T-shaped rigid frame bridge in Guangdong, the finite element modeling and calculation are carried out by using MIDAS CIVIL software. Combined with the regular detection, long-term deformation monitoring and static load test of the bridge, the health state of the bridge during operation is analyzed. The results show that: (1) the two diseases of bridge cantilever end deflection and lateral displacement of hanging beam are prominent, and the main influencing factors of cantilever end deflection are concrete shrinkage and creep. Such as prestress loss and temperature effect, the possible influencing factors of transverse displacement of hanging beam are asymmetrical deflection of cow leg, void of bearing and transverse load. (2) the influence of concrete shrinkage and creep on the deflection of the bridge is related to time, and the deflection disease mainly occurs within one year after the completion of the bridge, and then tends to be stable gradually; under the condition of prestress loss, the coefficient of deflection and prestress loss is approximately linear; the heating effect will slightly increase the deflection of the bridge in the side span, make the bridge produce large arch to balance the deflection disease in the main span, and vice versa; (3) the asymmetrical deflection of cow leg has no obvious effect on the lateral displacement of the hanging beam; the clearance of the bearing will increase the transverse displacement of the hanging beam, and the influence of the emptiness of the bearing will be greater than that of the two supports; the greater the wind speed, the greater the lateral displacement of the bridge, but the wind from the outside is beneficial to the disease of moving out of the hanging beam. (4) the bridge has been safely operated for 20 years. Since 2007, the deflection of the bridge deck has changed little and the alignment has been smooth. The results of periodic test show that there are some diseases, such as sand accumulation of expansion joint, slight void of support, spalling of concrete of beam body and pier, corrosion of exposed tendons, etc. The results of static load test show that the structural performance meets the design requirements at present. The analysis of this paper proves that the deflection change of the main bridge and the transverse displacement of the hanging beam are the results of many factors. Although the monitoring shows that the deflection and lateral displacement of the bridge have little change since reinforcement, and the stress state is good, it is still necessary to continue to carry on the long-term health monitoring and regular inspection of the bridge, detect and predict the structural diseases in time, and ensure the safe operation of the bridge.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U445.7;U448.23
，
本文编号：2501300
[Abstract]:T-shaped rigid frame bridge has been widely used as soon as it came out in the second half of the last century. With the increase of operation time and the long-term effect of vehicle load, T-shaped rigid frame bridge is prone to deflection, displacement and other diseases, which affects the safe use of bridge structure. According to the regular inspection and long-term monitoring data of the bridge, the health state of the T-shaped rigid frame during operation is evaluated and studied, and the damage degree of the bridge structure is analyzed, and the bearing capacity and safety degree of the bridge are evaluated, which provides the basis for the maintenance and reinforcement of the bridge, and has certain theoretical and practical engineering significance. In this paper, based on the long-term deformation monitoring and regular detection project of a T-shaped rigid frame bridge in Guangdong, the finite element modeling and calculation are carried out by using MIDAS CIVIL software. Combined with the regular detection, long-term deformation monitoring and static load test of the bridge, the health state of the bridge during operation is analyzed. The results show that: (1) the two diseases of bridge cantilever end deflection and lateral displacement of hanging beam are prominent, and the main influencing factors of cantilever end deflection are concrete shrinkage and creep. Such as prestress loss and temperature effect, the possible influencing factors of transverse displacement of hanging beam are asymmetrical deflection of cow leg, void of bearing and transverse load. (2) the influence of concrete shrinkage and creep on the deflection of the bridge is related to time, and the deflection disease mainly occurs within one year after the completion of the bridge, and then tends to be stable gradually; under the condition of prestress loss, the coefficient of deflection and prestress loss is approximately linear; the heating effect will slightly increase the deflection of the bridge in the side span, make the bridge produce large arch to balance the deflection disease in the main span, and vice versa; (3) the asymmetrical deflection of cow leg has no obvious effect on the lateral displacement of the hanging beam; the clearance of the bearing will increase the transverse displacement of the hanging beam, and the influence of the emptiness of the bearing will be greater than that of the two supports; the greater the wind speed, the greater the lateral displacement of the bridge, but the wind from the outside is beneficial to the disease of moving out of the hanging beam. (4) the bridge has been safely operated for 20 years. Since 2007, the deflection of the bridge deck has changed little and the alignment has been smooth. The results of periodic test show that there are some diseases, such as sand accumulation of expansion joint, slight void of support, spalling of concrete of beam body and pier, corrosion of exposed tendons, etc. The results of static load test show that the structural performance meets the design requirements at present. The analysis of this paper proves that the deflection change of the main bridge and the transverse displacement of the hanging beam are the results of many factors. Although the monitoring shows that the deflection and lateral displacement of the bridge have little change since reinforcement, and the stress state is good, it is still necessary to continue to carry on the long-term health monitoring and regular inspection of the bridge, detect and predict the structural diseases in time, and ensure the safe operation of the bridge.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U445.7;U448.23
，
本文编号：2501300
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