重载交通对高速公路桥梁的疲劳影响研究

发布时间：2018-05-12 10:38

本文选题：重载交通 + 荷载谱　；参考：《河北工业大学》2015年博士论文

【摘要】：随着交通运输事业的不断发展,公路桥梁上的车辆荷载类型发生了巨大变化,重载化趋势非常明显。当重载车辆从桥梁上频繁通过时,将会对桥梁造成严重损害,甚至可能导致梁体构件的开裂,尤其当桥梁开裂后,尽管卸载时所产生的裂缝会暂时闭合,但是这种损伤会导致该桥的承载能力下降,甚至不能够正常使用。对于旧桥大多就已具有裂缝,由于重载车辆的频繁驶过会导致裂缝的开展加剧,最终甚至会致使桥梁垮塌。因此,为了确保桥梁的运营安全,并为建设单位和桥梁运营管理部门提供技术参考依据,本文对河北省内多条高速公路进行交通调查和室内疲劳试验研究,主要研究工作如下:1、通过对河北省内多条高速公路的交通量、交通组成、轴重、轴距、车辆时速和车辆间距等基础数据进行实际调查与收集,分析不同车型、不同载重等级车辆所占比率,确定其概率分布规律;依据疲劳等效损伤原理,统计得出了实际车辆的荷载谱;将其与规范公路—Ⅰ级汽车荷载作用效应进行比较,提出重载交通下汽车荷载提高系数。2、采用四阶段法对未来的京港澳高速公路进行交通预测,并分析未来交通量变化的主要影响因素;通过分别对四车道和六车道高速公路进行现场实际调查,得出重载车辆分车道行驶规律;分别采用灰色GM(1,1)预测模型、BP神经网络预测模型和灰色-BP神经网络组合预测模型对六车道(八车道)高速公路重载车辆行驶规律进行预测,预测结果表明:应用灰色-BP神经网络组合预测模型预测精度为优秀,预测精度最高。3、以京港澳高速公路(京石段)改扩建工程中的16米标准跨径预应力混凝土梁为研究背景,经过合理的缩尺模型,通过室内等幅疲劳试验研究其在长期重载作用下预应力混凝土梁的疲劳性能,如:混凝土应变的变化规律、非预应力钢筋的变化规律、预应力钢筋的变化规律、挠度变化、裂缝的发展规律、刚度退化情况以及在重载作用下的容许疲劳寿命等问题。4、通过室内变幅疲劳试验,研究了预应力混凝土梁在两级变幅疲劳荷载作用下的破坏形态和破坏特征,得到了加载顺序和荷载水平对预应力混凝土梁疲劳寿命的影响;分别利用Miner准则和修正的Miner准则对变幅疲劳寿命进行了估算,计算结果表明:由Miner准则估算对变幅疲劳试验的容许疲劳寿命预测是偏于危险的,而由修正的Miner准则估算的容许疲劳寿命精度较高,而且更偏于保守;通过两级变幅疲劳试验得出容许疲劳累积损伤临界值DCR为0.8。5、利用有限元分析软件对16米跨径预应力混凝土简支梁建立实体模型,依据交通调查数据统计分析结果,结合其相关分布规律,运用蒙特卡洛(Monte Carlo)方法并借助Matlab软件编制随机车流仿真程序,将典型车辆模型和随机车辆模型分别加载到桥梁有限元模型上,模拟实际运营车辆过桥的情况,采用有限元软件进行瞬态动力分析。运用疲劳累积损伤理论分别计算各典型车辆在不同车辆间距下、不同车速条件下,密集运营状态下和一般运营状态下桥梁的疲劳损伤情况。
[Abstract]:With the continuous development of traffic and transportation, the type of vehicle load on the highway bridge has changed greatly, and the trend of heavy loading is very obvious. When heavy vehicles are frequently outdated from the bridge, it will cause serious damage to the bridge, even may lead to the cracking of the beam components, especially when the bridge is cracked, despite the cracking of the unloading. The seams will be closed temporarily, but this damage will lead to a decline in the bearing capacity of the bridge or even the normal use. Most of the old bridges have cracks. The frequent passing of heavy vehicles will lead to the intensification of the cracks and eventually the collapse of the bridge. Therefore, in order to ensure the safety of the bridge operation, and for the construction unit and the construction unit, The bridge operation management department provides the technical reference basis, this article carries on the traffic investigation and the indoor fatigue test research to several freeways in Hebei province. The main research work is as follows: 1, through the traffic volume, traffic composition, axle weight, axle distance, vehicle speed and vehicle distance, the basic data of Hebei province are adjusted. Check and collect, analyze the proportion of different vehicles and different load grade vehicles and determine their probability distribution law. According to the principle of fatigue equivalent damage, the load spectrum of actual vehicles is obtained. Compared with the standard highway I grade car load effect, the increase coefficient.2 of vehicle load under heavy load traffic is put forward, and the four stage is adopted. The future traffic forecast of Beijing, Hong Kong and Macao expressway is carried out, and the main influencing factors of the future traffic change are analyzed. Through the actual investigation of the four lane and six lane freeways, the driving laws of the heavy vehicles are obtained. The grey GM (1,1) prediction model, the BP neural network prediction model and the grey -BP God are used respectively. Through the combined forecasting model of the six lane (eight Lane) highway, the forecasting results show that the prediction accuracy of the combined grey -BP neural network combined forecasting model is excellent and the prediction precision is.3, and the 16 meter standard span prestressed concrete in the reconstruction and extension project of Beijing Hong Kong Macau Expressway (Jingshi section) As the research background, through a reasonable scale model, the fatigue performance of prestressed concrete beams under long-term heavy load, such as the change law of concrete strain, the change rule of non prestressed reinforcement, the change rules of the prestressed reinforcement, the change of the deflection, the law of the development of the crack and the degenerate condition of the stiffness, are studied through the reasonable scale model. The failure mode and damage characteristics of prestressed concrete beams under two stage variable amplitude fatigue load are studied through indoor variable amplitude fatigue test. The effect of loading sequence and load level on fatigue life of prestressed concrete beams is obtained by indoor variable amplitude fatigue test, and the effect of loading sequence and load level on fatigue life of Prestressed concrete beams is obtained, and Miner criterion and repair are used respectively. The variable amplitude fatigue life is estimated by the positive Miner criterion. The calculation results show that the prediction of permissible fatigue life of the variable amplitude fatigue test is biased by the Miner criterion, and the allowable fatigue life accuracy estimated by the modified Miner criterion is higher and more conservative, and the permissible fatigue is obtained through the two stage variable amplitude fatigue test. The critical value of product damage is DCR 0.8.5. The finite element analysis software is used to establish the solid model of 16 meter span prestressed concrete simple supported beam. According to the statistics and analysis results of traffic investigation data, combined with the relevant distribution rules, the Monte Carlo (Monte Carlo) method is used and the simulation program of random traffic flow is compiled with the aid of Matlab soft parts, and the typical vehicle model is built. And the random vehicle model is loaded on the bridge finite element model respectively to simulate the actual operating vehicle crossing the bridge. The transient dynamic analysis is carried out by the finite element software. The fatigue cumulative damage theory is used to calculate the bridge under the different vehicle spacing, the different vehicle speed conditions, the dense operation state and the general operating state. The fatigue damage of the beam.

【学位授予单位】：河北工业大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：U441.4

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