重载公路小跨径PC梁桥疲劳车辆荷载谱与疲劳性能研究
发布时间：2018-12-10 16:30
【摘要】：桥梁的安全问题一直受业内人士的关注,桥梁使用寿命的设计基准期一般为100年,随着我国社会经济的发展,我国公路运输的交通流量和车辆荷载都呈增长趋势,特别是在我国自然资源丰富的中西部地区,交通荷载具有大流量、高轴载的特点,公路桥梁在长期高轴载作用下,会加剧桥梁的损坏,严重影响桥梁的使用寿命,车辆荷载对桥梁结构的疲劳损伤不容忽视。我国《公路桥涵设计通用规范》(JTGD60-2004)中规定了桥梁的车辆荷载分为公路-Ⅰ级和公路-Ⅱ级两个等级,汽车荷载由车道荷载和车辆荷载组成,尚缺乏用于公路桥梁疲劳性能评估的疲劳荷载谱,且针对公路桥梁疲劳设计的车辆荷载目前的研究还不够深入。本文针对重载公路货运通道的车辆荷载进行研究,并选取典型桥梁进行疲劳寿命预测。主要工作内容如下：(1)选取重载公路货运通道典型路段对车辆类型、车间距、车重和车辆横向分布情况进行了现场调查与统计分析,拟合出车间距和各车型车重分布的概率密度函数,根据由Miner准则推导出的等效轴重和等效轴距计算公式,将具有相同轴数的不同车辆简化为一种典型车辆模型,最终得到适用于重载公路疲劳计算的疲劳车辆荷载频值谱,通过计算各车型对桥梁的损伤度,选择贡献最大的车型作为标准疲劳车的基本形式,并对不同跨径的简支梁桥计算其轴重修正系数,建立基于20m简支梁的标准疲劳车辆模型。(2)根据实际调查的交通数据,运用Matlab编写程序,模拟车辆荷载的随机过程,选取13m简支板梁和20m简支T梁,对其进行跨中弯矩影响线加载,计算在模拟的随机车辆荷载作用下的弯矩时间历程,并运用雨流计数法计算弯矩幅和统计弯矩幅的分布规律,拟合得到两种梁型的弯矩幅分布概率密度函数。(3)利用ANSYS对两种简支梁进行加载破坏全过程分析,确定其开裂荷载、屈服荷载和破坏荷载。为了确定所选梁型在调查的荷载作用下的使用寿命,引入基于应力的疲劳寿命预测方法对其疲劳寿命预测分析;建立各材料的疲劳本构关系,应用ANSYS有限元软件计算简支梁经过不同次数疲劳荷载作用后的剩余承载力,结果表明,随着疲劳荷载作用次数的增加,简支梁的疲劳剩余承载力一直呈下降趋势。
[Abstract]:The safety problem of bridges has been concerned by the industry all the time. The design reference period of bridge service life is generally 100 years. With the development of our country's social economy, the traffic flow and vehicle load of highway transportation in our country are increasing. Especially in the central and western regions rich in natural resources, traffic load has the characteristics of large discharge and high axial load. Under the action of long-term high axial load, highway bridge will aggravate the damage of the bridge and seriously affect the service life of the bridge. The fatigue damage of bridge structure caused by vehicle load can not be ignored. The General Code for Design of Highway Bridges and culverts (JTGD60-2004) stipulates that the vehicle loads of bridges are divided into two classes: highway class 鈪，
本文编号：2370877
[Abstract]:The safety problem of bridges has been concerned by the industry all the time. The design reference period of bridge service life is generally 100 years. With the development of our country's social economy, the traffic flow and vehicle load of highway transportation in our country are increasing. Especially in the central and western regions rich in natural resources, traffic load has the characteristics of large discharge and high axial load. Under the action of long-term high axial load, highway bridge will aggravate the damage of the bridge and seriously affect the service life of the bridge. The fatigue damage of bridge structure caused by vehicle load can not be ignored. The General Code for Design of Highway Bridges and culverts (JTGD60-2004) stipulates that the vehicle loads of bridges are divided into two classes: highway class 鈪，
本文编号：2370877
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