Considering arch rib, lateral brace, suspender, girder, pier and track position, the model for the interaction between long-span tied arch continuous bridge and multiple tracks was established by using steel-concrete ...Considering arch rib, lateral brace, suspender, girder, pier and track position, the model for the interaction between long-span tied arch continuous bridge and multiple tracks was established by using steel-concrete composite section beam element to simulate concrete-filled steel tube(CFST) arch rib, using the beam element with rigid arm to simulate the prestressed concrete girder and using nonlinear bar element to simulate longitudinal constraint between track and bridge. Taking a(77+3×156.8+77) m tied arch continuous bridge with four tracks on the Harbin-Qiqihar Passenger Dedicated Line as an example, the arrangement of continuously welded rail(CWR) was explored. The longitudinal force in CWR on the tied arch continuous bridge, the pier top horizontal force and torque due to the unbalance load case, were analyzed under the action of temperature, vertical live load, train braking and wind load.Studies show that, it can significantly reduce track displacement to set the track expansion devices at main span arch springing on both sides; the track stress due to arch temperature variation can reach 40.8 MPa; the track stress, pier top horizontal force and torque are related to the number of loaded tracks and train running direction, and the bending force applied to unloaded track is close to the loaded track, while the braking force applied to unloaded track is 1/4 to 1/2 of the loaded track; the longitudinal force of track due to the wind load is up to 12.4 MPa, which should be considered.展开更多
针对传统方法子指标的不确定性问题,提出了一种基于三角直觉模糊网络分析法(triangular intuitionistic fuzzy analytic network process,TIFANP)、优劣解距离法(technique for order preference by similarity to an ideal solution,TO...针对传统方法子指标的不确定性问题,提出了一种基于三角直觉模糊网络分析法(triangular intuitionistic fuzzy analytic network process,TIFANP)、优劣解距离法(technique for order preference by similarity to an ideal solution,TOPSIS)和三角直觉模糊综合评价(triangular intuitionistic fuzzy comprehensive evaluation,TIFCE)的大跨桥梁安全状态评估方法。首先,建立大跨桥梁安全状态分层指标体系,采用TIFANP法确定考虑指标相互影响后的权重;其次,引入TOPSIS法分配指标各截面权重,进而获得子指标取值;然后,将桥梁安全状态划分为5级,通过TIFCE法构建指标在不同等级的隶属度和非隶属度函数,据此建立对应判断矩阵,并进行桥梁安全状态指数综合计算;最后,以某大跨悬索桥监测数据为依托,验证了所提方法的有效性。结果表明:所提方法能够更合理地处理评价指标间的相互影响以及专家评分时的不确定,可为运营期大跨桥梁安全状态的准确评估提供新思路。展开更多
现有大跨径桥梁有限元模型修正(finite element model updating,FEMU)方法一般未考虑运营荷载对结构动力特性的影响,导致修正后模型的参数变异性大。鉴于此,提出了一种考虑运营荷载的层次贝叶斯有限元模型修正方法,该方法包含考虑温度...现有大跨径桥梁有限元模型修正(finite element model updating,FEMU)方法一般未考虑运营荷载对结构动力特性的影响,导致修正后模型的参数变异性大。鉴于此,提出了一种考虑运营荷载的层次贝叶斯有限元模型修正方法,该方法包含考虑温度和交通荷载的概率参数修正、概率响应预测和结构状态评估。首先,根据监测数据的相关性分析结果确定了计算理论频率时需要考虑的荷载。随后,建立了温度-弹性模量线性关系,并基于动态称重(weigh-in-motion,WIM)数据,提出一种车辆荷载估计方法,以在有限元模型中定量考虑运营荷载对结构频率的影响。同时,引入两阶段马尔科夫链蒙特卡洛(Markov chain Monte Carlo,MCMC)采样方法和响应面代理模型,以提高概率模型修正的计算速率。该方法在一座采集了两年监测数据的大跨径拱桥上得到了验证。结果表明,在考虑运营荷载、参数不确定性和建模误差后,实测频率基本处于预测频率的95%置信区间内。最后,基于实测响应和预测响应置信区间提出了一个结构状态指标,并利用该指标检测出该桥的路面铺装更换过程。展开更多
基金Project(51378503)supported by the National Natural Science Foundation of ChinaProject(2014M552158)supported by China Postdoctoral Science Foundation
文摘Considering arch rib, lateral brace, suspender, girder, pier and track position, the model for the interaction between long-span tied arch continuous bridge and multiple tracks was established by using steel-concrete composite section beam element to simulate concrete-filled steel tube(CFST) arch rib, using the beam element with rigid arm to simulate the prestressed concrete girder and using nonlinear bar element to simulate longitudinal constraint between track and bridge. Taking a(77+3×156.8+77) m tied arch continuous bridge with four tracks on the Harbin-Qiqihar Passenger Dedicated Line as an example, the arrangement of continuously welded rail(CWR) was explored. The longitudinal force in CWR on the tied arch continuous bridge, the pier top horizontal force and torque due to the unbalance load case, were analyzed under the action of temperature, vertical live load, train braking and wind load.Studies show that, it can significantly reduce track displacement to set the track expansion devices at main span arch springing on both sides; the track stress due to arch temperature variation can reach 40.8 MPa; the track stress, pier top horizontal force and torque are related to the number of loaded tracks and train running direction, and the bending force applied to unloaded track is close to the loaded track, while the braking force applied to unloaded track is 1/4 to 1/2 of the loaded track; the longitudinal force of track due to the wind load is up to 12.4 MPa, which should be considered.
文摘针对传统方法子指标的不确定性问题,提出了一种基于三角直觉模糊网络分析法(triangular intuitionistic fuzzy analytic network process,TIFANP)、优劣解距离法(technique for order preference by similarity to an ideal solution,TOPSIS)和三角直觉模糊综合评价(triangular intuitionistic fuzzy comprehensive evaluation,TIFCE)的大跨桥梁安全状态评估方法。首先,建立大跨桥梁安全状态分层指标体系,采用TIFANP法确定考虑指标相互影响后的权重;其次,引入TOPSIS法分配指标各截面权重,进而获得子指标取值;然后,将桥梁安全状态划分为5级,通过TIFCE法构建指标在不同等级的隶属度和非隶属度函数,据此建立对应判断矩阵,并进行桥梁安全状态指数综合计算;最后,以某大跨悬索桥监测数据为依托,验证了所提方法的有效性。结果表明:所提方法能够更合理地处理评价指标间的相互影响以及专家评分时的不确定,可为运营期大跨桥梁安全状态的准确评估提供新思路。
文摘现有大跨径桥梁有限元模型修正(finite element model updating,FEMU)方法一般未考虑运营荷载对结构动力特性的影响,导致修正后模型的参数变异性大。鉴于此,提出了一种考虑运营荷载的层次贝叶斯有限元模型修正方法,该方法包含考虑温度和交通荷载的概率参数修正、概率响应预测和结构状态评估。首先,根据监测数据的相关性分析结果确定了计算理论频率时需要考虑的荷载。随后,建立了温度-弹性模量线性关系,并基于动态称重(weigh-in-motion,WIM)数据,提出一种车辆荷载估计方法,以在有限元模型中定量考虑运营荷载对结构频率的影响。同时,引入两阶段马尔科夫链蒙特卡洛(Markov chain Monte Carlo,MCMC)采样方法和响应面代理模型,以提高概率模型修正的计算速率。该方法在一座采集了两年监测数据的大跨径拱桥上得到了验证。结果表明,在考虑运营荷载、参数不确定性和建模误差后,实测频率基本处于预测频率的95%置信区间内。最后,基于实测响应和预测响应置信区间提出了一个结构状态指标,并利用该指标检测出该桥的路面铺装更换过程。
