某高速公路车辆轴载统计及其对桥面板的影响分析

针对高速公路车辆轴重的变异问题,基于车辆动态测重数据,统计分析各类车型的车重、轴重和超载数据,计算在实际超载情况下三轴车、六轴车的轴重对桥面板产生的应力,并与标准车辆荷载进行加载比较。结果表明:轴重的发展变异程度很大,三轴车和六轴车对桥面板产生的弯矩和剪力影响约是标准车辆荷载的2.1倍,其在根部产生的弯拉应力约为标准车辆的2倍,三轴车轴重与六轴重车产生的内力、应力值相当。本研究旨在对当前车辆超载轴重变异性的评估、计重收费模式的完善和既有桥梁的维护提供借鉴。     

基于WIM的北京市G103国道车辆荷载模型研究

为了评估北京市G103国道上在役桥梁的承载能力,需要对实际交通流作用下的公路桥梁车辆荷载模型进行研究。笔者基于动态称重系统WIM实测的交通轴载数据,结合JTG D60—2004《公路桥涵设计通用规范》和JTJ D62—2004《公路钢筋混凝土及预应力桥涵设计规范》中车辆荷载模型的建立方法 ,对车辆总重、轴重等参数进行统计分析,拟定符合北京市G103国道实际交通状况的车辆荷载参数,并提出了2-1-3轴型的典型6轴重型车辆荷载模型。在此基础上,分别采用实测车辆荷载模型和规范车辆荷载模型对大柳树2号桥梁的车辆活载效应进行分析,结果表明:实测车辆荷载模型各参数均与规范建议值有较大差异,其车辆活载效应比规范车辆荷载模型的计算结果增加了20%~50%,超重车辆对在役桥梁安全性能存在较大威胁。     

不同运行状态下的城市桥梁标准疲劳车模型研究

以乌鲁木齐市某高架桥获取的3个月实地车辆拥堵荷载数据为基础,采用等效损伤原则计算了由原始车辆荷载谱等效得到的疲劳车加载到1.5～100m简支梁和30m+30m+30m连续梁桥产生的疲劳损伤占比,推导了适用于乌市一般运行状态下的标疲车。此外,选取了两种频发的怠速拥堵工况,按"总重不变,合并轴重"原则分别近似等效为3轴和4轴疲劳车,并计算了加载到1.2～50m简支梁上产生的疲劳损伤占比,推导了适用于乌市拥堵状态下的标疲车。最后,对比分析了一般运行状态和拥堵状态下以及国内外的标疲车对桥梁造成的疲劳损伤随桥梁跨径变化的差异和规律。     

基于实测数据的大跨桥梁疲劳标准车模型研究

车辆荷载是变异性很大的随机变量,其荷载模型因时间、地区的差异而显著不同,为确定车辆荷载的准确分布类型和统计参数,需要大量的资料和实测数据。依托舟山跨海大桥WIM系统监测的车流信息,即车型、总重、轴重及轴距等进行分析,提出数值模拟所需疲劳车辆荷载的新思路和实施细则,包括确定多类疲劳标准车总重、轴重、轴距等关键问题,对我国桥梁结构疲劳标准车荷载的设计与完善具有一定的指导意义。     

基于WIM的钢-混组合梁桥疲劳荷载模型研究

为研究钢-混组合梁桥疲劳荷载模型,采用动态称重系统(WIM)获取山东地区高速公路10个月的交通荷载数据,建立有限元模型分析车型、总重对疲劳评估结果的影响规律,基于等效损伤理论对疲劳荷载模型进行推导。研究结果表明:外侧车道存在42.0%的疲劳致伤车辆,其中二轴货车比例最高、六轴货车次之,五轴货车最少;交通荷载总重呈多峰分布特点,峰值集中于30kN、130kN、350kN,超载车辆占比不足1%;提出的钢-混组合梁桥疲劳荷载模型推导方法可行,建立了总重315kN的钢-混组合梁桥疲劳荷载模型,供同类型桥梁疲劳评估时参考使用。     

桥梁超重荷载分析与限载标准确定

以陕西府店路运煤超重车辆为调查对象,由车辆载重特点和轴型分布特征将其分为9种类型;分析了此9种车辆模型超载超限情况。利用线性回归方法,得出超载与超限的函数关系,分析了二者的区别与内在联系;对道路桥梁上的超重车辆荷载,提出限载管理措施。利用等代荷载方法,与公路-Ⅰ级荷载相比较,确定出9种车型的限载系数和限载标准,评价了限载后车辆荷载特性,得出了车辆限载后提倡使用多轮、多轴的车型来装运的结论,为未来道路桥梁超重荷载管理、交通运输与路政管理提供理论依据与支持。     

当量轴次与交通流量之间的关系

以大量的轴重检测数据为基础,根据当量轴次与单轴轴重和车流量之间关系,推导出不同超载情况下的当量轴次与交通流量之间的相互关系.     

考虑动力作用的公路车辆荷载统计

依据车重及轴组将车辆划分为7类,对每一类车辆统计其车重、轴重、轴距、车间距的分布模型.在此基础上将车型归并为3类,得到其等效轴重、等效轴距.然后引入了正弦形式的车辆动力荷载,提出了考虑车辆动力作用的等效车辆模型.     

重庆地区公路桥梁车辆荷载轴重调查研究

基于重庆市高速公路发展有限公司提供的一周WIM数据,对不同类型的车型(轴型)出现概率统计出7种常见车型(轴型),并且对总轴重样本与分轴重样本进行了荷载频率统计、曲线拟合、函数拟合以及分布假设与检验,得出重庆市现有高速公路交通流量的总轴重(车重)基本满足要求的结论.     

车辆荷载作用下公路软基沉降的拟静力计算方法研究

基于车辆动荷载的特点和我国车辆普遍超载的现状，将车辆动荷载等效简化为静荷载，并假定了简化后等效静荷载的3种分布形式：集中分布、矩形分布和带状分布。依据Boussinesq解答和Flamant解答推导出3种分布形式下的计算公式，再应用分层总和法计算车辆动荷载作用下公路软土地基的沉降量。以沪宁高速公路4个断面为例，应用拟静力法研究了3种荷载分布形式下车辆动荷载对高速公路软土地基沉降的影响，研究结果表明：由超重车辆引起的地基沉降量可以达到厘米量级，车辆荷载的影响深度大约在12m范围以内。     

A filtering-based bridge weigh-in-motion system on a continuous multi-girder bridge considering the influence lines of different lanes

A real-time vehicle monitoring is crucial for effective bridge maintenance and traffic management because overloaded vehicles can cause damage to bridges, and in some extreme cases, it will directly lead to a bridge failure. Bridge weigh-in-motion (BWIM) system as a high performance and cost-effective technology has been extensively used to monitor vehicle speed and weight on highways. However, the dynamic effect and data noise may have an adverse impact on the bridge responses during and immediately following the vehicles pass the bridge. The fast Fourier transform (FFT) method, which can significantly purify the collected structural responses (dynamic strains) received from sensors or transducers, was used in axle counting, detection, and axle weighing technology in this study. To further improve the accuracy of the BWIM system, the field-calibrated influence lines (ILs) of a continuous multi-girder bridge were regarded as a reference to identify the vehicle weight based on the modified Moses algorithm and the least squares method. In situ experimental results indicated that the signals treated with FFT filter were far better than the original ones, the efficiency and the accuracy of axle detection were significantly improved by introducing the FFT method to the BWIM system. Moreover, the lateral load distribution effect on bridges should be considered by using the calculated average ILs of the specific lane individually for vehicle weight calculation of this lane.     

Vehicle models for fatigue loading on steel box-girder bridges based on weigh-in-motion data

On the basis of massive data collected by the Weigh-in-motion (WIM) system of XiHouMen Bridge, analysis of fatigue-loaded vehicle models and theoretical fatigue life of U ribs butt weld of steel box girder are discussed in this paper. Firstly, basic vehicle information can be obtained from preliminary statistics of various types of vehicles data and the vehicles passing XiHouMen Bridge are divided into seven types based on the number of axles and axle groups. Secondly, the statistical distribution functions of gross vehicle weight under different loading conditions and wheelbase for each type of vehicle are developed to obtain the equivalent fatigue vehicle load. Then, the parameters of various types of fatigue-loaded vehicles are determined by combining the mathematic expectation of gross vehicle weight distribution with Palmgren-Miner fatigue damage accumulation theory. Finally, the seven types of fatigue-loaded vehicles are applied to the component-coupled finite element model of the steel box girders in XiHouMen Bridge and the theoretical fatigue life of the U ribs butt weld can be estimated. This research provides a reference to define the vehicle models for fatigue loading on steel box-girder bridges based on WIM data.     

大件运输中增设辅助桥墩加固法分析

随着我国现代化工业建设的发展,大件运输己日趋频繁,这些大件运输车辆具有总重和轴重大、通行次数少及行车速度慢等特点。从大件车辆及桥梁的考虑,依据大件运输中桥梁加固工程的特点,结合云南省某工程案例,针对大件运输车辆在中小跨径桥梁的通行要求,采用辅助桥墩法,运用有限元软件对加固前后的桥梁内力进行计算分析,结果表明辅助桥墩法能显著降低由活载作用产生的内力。     

Traffic load modelling based on structural health monitoring data

Live and fatigue load models are foundations for the life-cycle design of highway bridges. Many highway bridges are now equipped with structural health monitoring (SHM) systems, which provide valuable data to establish load models. In this paper, traffic load models of the Binzhou Yellow River Highway Bridge are developed based on the field measurement of vehicles by an existing SHM system. The probabilistic distribution model and extreme value distribution of gross vehicle weight are statistically analysed using the monitoring data. The results indicate that they follow the bimodal lognormal and Gumbel distributions, respectively. The fatigue load spectrum is also studied. The logistic model is employed to predict the long-term traffic volume, and its parameters of the logistic model are updated using the monitored traffic volume. The combination of the fatigue load spectrum and the traffic volume forecast using the updated logistic model provides a load model for estimation of fatigue damage evolution of bridges.     

聚酯纤维对沥青砼路用性能作用分析

随着我国公路交通的快速发展,交通量迅速增加、车速提高、交通渠化、轴载增加以及普遍的车辆超载现象,对高等级公路沥青路面所用的沥青混合料性能提出了更高的要求。有关研究表明,聚酯纤维的加入可提高混合料的综合路用性能,并能够在一定程度上改善沥青砼路面的长期使用性能。本文在此基础上分析了聚酯纤维对沥青砼路用性能作用机理。     

Nothing-on-road bridge weigh-in-motion considering the transverse position of the vehicle

Bridge weigh-in-motion (BWIM) is a technology that uses the bridge as a weighing platform to estimate vehicle weights. Previous research has shown that ignoring the transverse position (TP) of vehicles may lead to significant identification errors of vehicle weight for BWIM systems. However, the traditional method to identify the vehicle’s exact TP requires using axle detectors on the road surface. Aiming at achieving the nothing-on-road (NOR) BWIM, this paper proposes a novel NOR BWIM algorithm that is able to identify the vehicle’s TP and axle weights using only the weighing sensors. Numerical simulations are conducted using three-dimensional vehicle and bridge models and the proposed algorithm was used to identify the vehicle’s TP and axle weights. The results show that the proposed algorithm can successfully identify the vehicle’s TP and that the identification accuracy of axle weights and gross vehicle weight is significantly improved after considering the vehicle’s TP. The effects of the road surface condition, the vehicle speed, the vehicle width, and different measurement stations on the identification accuracy are investigated. The proposed algorithm is then verified by a field study and the results indicate that the proposed algorithm can achieve acceptable identification accuracy in practice.     

城市道路桥梁的疲劳荷载谱

我国针对公路及城市道路桥梁疲劳设计的车辆荷载谱还是个空白,本文以上海市内环线中山路3号桥地面道路桥梁为例,对城市道路桥梁的疲劳荷载作了研讨.在1994年和1995年两次交通调查的基础上,得到了由18类日常典型的运营车辆组成的荷载频值谱.依据等效的疲劳损伤原理,将实测的车辆荷载频值谱简化成由6类模型车辆组成的具有实用性的荷载频值谱.所建立的模型车辆荷载频值谱,对于日常车辆交通构成与本文状况相类似的其它城市道路桥梁的疲劳损伤度验算,可作为参考.     

同时考虑速度和轴跨比影响时铁路钢桥的影响因子的确定

传统桥梁设计方法中,把交通荷载处理为静载乘以影响因子。依据现行规范,该因子仅是跨度或一阶自振频率的函数。分析各种参数对钢桥动力响应的影响,包括:速度、火车轴距、车轴数、桥跨度,并研究影响因子。计算了火车速度100～400km/h,轴距13～20m,桥跨度10,15,20,25m情况下的动力响应和影响因子。动力分析表明,大多数情况下,算得的影响因子高于相关规范中的值。影响因子随火车速度、火车轴距和桥跨度之比而变化,而车轴数仅在共振时产生影响。给出了速度、车轴距、桥跨度与影响因子的关系。     

Modelling the spatial distribution of heavy vehicle loads on long-span bridges based on undirected graphical model

Abstract

Vehicle load modelling is highly important for bridge design and safety evaluation. Conventional modelling approaches for vehicle loads have limitations in characterizing the spatial distribution of vehicles. This article presents a probabilistic method for modelling the spatial distribution of heavy vehicle loads on long-span bridges by using the undirected graphical model (UGM). The bridge deck is divided into grid cells, a UGM with each node corresponding to each cell is employed to model the location distribution of heavy vehicles, by which probabilities of heavy-vehicle distribution patterns can be efficiently calculated through applying the junction tree algorithm. A Bayesian inference method is also developed for updating the location model in consideration of the non-stationarity of traffic process. Gross weights of heavy vehicles are modelled by incorporating additional random variables to the vehicle-location UGM, corresponding probability distributions are constructed conditioned on ignoring correlation and considering correlation, respectively. Case studies using simulated data as well as field monitoring data have been conducted to examine the method. Compared with previous studies involving vehicle load modelling, the presented method can implement probabilistic analysis for all spatial distribution patterns of heavy vehicles on the entire bridge deck.     

超重车途经河源市胜利大桥安全评估

随着交通运输业的发展,超重车过桥的情况日益增多。以河源市胜利大桥为例,以有限元分析手段建立桥梁分析模型,根据超重车参数抽象出车辆荷载模型,对超重车过桥的过程进行模拟计算。在对承载力分析的基础上研究了全桥的安全程度,给出了超重车过桥的决策建议及相关保障措施。研究成果可为类似情况提供参考和帮助。