基于几何线形的立交噪声计算方法

为定量评价道路几何线形对立交噪声的影响,研究了基于几何线形计算立交噪声的方法,以车辆行驶速度为切入点,拟合噪声级和车速之间的关系.对于匝道噪声的计算,根据等效声级的定义给出了相对等效声能量的含义及计算方法,采用将匀速运动段与变速运动段噪声能量相加的方法求出总的噪声能量,建立了相对等效声能量与匝道长度之间函数关系,用对匝道长度进行积分的方法,根据等效声级的定义式推导出左、右转匝道的噪声级.根据主线设计速度、噪声级和车速之间的关系推导出主线噪声级计算公式.立交总噪声通过对各条主线和匝道的噪声级叠加求得.通过对黑龙江省鹤大立交的实例分析表明,该方法能够解决立交匝道变速运动段的噪声计算问题,能够将车辆在立交行驶产生的噪声与道路几何线形联系起来.当道路立交的几何设计条件已知,可以根据几何线形参数进行噪声污染计算,为定量评价立交噪声污染程度提供依据.     

基于DWT的路面不平度模拟的研究

为了更好地模拟实测路面不平度,提出了基于DWT的FD过程路面不平度模型.与传统的AR模型相比,该模型模拟的等级路面不平度精度高且时间开销小.利用离散小波变换对FD过程去相关,并采用平稳或非平稳FD过程最大可能性估计,对实测路面不平度进行了模拟,结果表明:所模拟的路面不平度与实测路面不平度比较相近.     

Accident history,risk perception and traffic safe behaviour

Abstract

This study clarifies the associations between accident history, perception of the riskiness of road travel and traffic safety behaviours by taking into account the number and severity of accidents experienced. A sample of 525 road users in Cameroon answered a questionnaire comprising items on perception of risk, safe behaviour and personal accident history. Participants who reported involvement in more than three accidents or involvement in a severe accident perceived road travel as less risky and also reported behaving less safely compared with those involved in fewer, or less severe accidents. The results have practical implications for the prevention of traffic accidents.

Practitioner Summary: The associations between accident history, perceived risk of road travel and safe behaviour were investigated using self-report questionnaire data. Participants involved in more than three accidents, or in severe accidents, perceived road travel as less risky and also reported more unsafe behaviour compared with those involved in fewer, or less severe accidents. Campaigns targeting people with a less serious, less extensive accident history should aim to increase awareness of hazards and the potential severity of their consequences, as well as emphasising how easy it is to take the recommended preventive actions. Campaigns targeting those involved in more frequent accidents, and survivors of serious accidents, should address feelings of invulnerability and helplessness.     

大跨径混凝土箱梁桥有效温度与应变的实测分析

基于苏通大桥辅助航道桥运营期两年内实测的温度、气象和应变数据,对混凝土箱梁的有效温度与应变进行了分析。结果表明:箱梁的尺寸越小,有效温度变化的范围越大,设计基准期为100年的墩顶梁和跨中箱梁的有效温度范围分别为(-4.3℃,37.3℃)和(-6.1℃,42.2℃);大气前3天的最高(低)平均温度与箱梁有效温度的相关性系数高达0.97,通过回归分析得到的箱梁有效温度与大气前3天平均最高(低)温度的关系式,可用来对箱梁有效温度进行预测。最后提出了修正混凝土收缩、徐变效应的方法,并使用箱梁有效温度对主墩墩底混凝土的竖向相对应变和支座截面箱梁顶板混凝土的纵向相对应变进行了预测。     

沥青混合料在冻融循环作用下的弯拉特性

通过沥青混合料在冻融循环作用下的弯曲试验,分析了冻融循环次数、油石比、级配组成对混合料弯拉特性的影响。试验结果表明:随着冻融循环次数的增多,沥青混合料的弯拉强度、弯拉应变、劲度模量均呈减小趋势。油石比、级配组成对弯拉特性有明显影响,随着油石比的增大,冻融循环作用对沥青混合料弯拉特性的影响减小,AC-13混合料的弯拉特性优于其他两种级配。在青藏高原寒冷地区采用AC-13的沥青混合料、油石比为5.5%或适当增加油石比可以提高沥青混合料在冻融循环作用下的低温弯曲特性。     

天津西站配套市政公用工程中道桥项目后评价指标研究

天津西站交通枢纽配套市政公用工程项目作为一项重大工程,意义重大.道桥工程作为重要的子项目之一,根据相关要求,必须进行项目后评价.科学设置相应的评价指标,对提升后评价的科学性具有重要作用.本文基于道桥工程的特点,从系统的角度出发,在投资决策过程、项目实施过程、项目效果和经济效益、项目环境和社会效益、项目目标和可持续发展几方面开展研究,以期为道桥项目的后评价提供依据.     

Comparison of two suspension control strategies for multi-axle heavy truck

Two simple and effective control strategies for a multi-axle heavy truck, modified skyhook damping (MSD) control and proportional-integration-derivative (PID) control, were implemented into functional virtual prototype (FVP) model and compared in terms of road friendliness and ride comfort. A four-axle heavy truck-road coupling system model was established using FVP technology and validated through a ride comfort test. Then appropriate passive air suspensions were chosen to replace the rear tandem suspensions of the original truck model for preliminary optimization. The mechanical properties and time lag of dampers were taken into account in simulations of MSD and PID semi-active dampers implemented using MATLAB/Simulink. Through co-simulations with Adams and MATLAB, the effects of semi-active MSD and PID control were analyzed and compared, and control parameters which afforded the best comprehensive performance for each control strategy were chosen. Simulation results indicate that compared with the passive air suspension truck, semi-active MSD control improves both ride comfort and road-friendliness markedly, with optimization ratios of RMS vertical acceleration and RMS tyre force ranging from 10.1% to 44.8%. However, semi-active PID control only reduces vertical vibration of the driver’s seat by 11.1%, 11.1% and 10.9% on A, B and C level roads respectively. Both strategies are robust to the variation of road level.     

“卓越计划”下课程设计整合的研究——以土木工程道路方向为例

通过分析土木工程专业道路方向课程设计整合起因,提出课程设计整合应遵循系统性、综合性、开放性原则,从整合设计内容、设计方法、实施主体等几个方面分析,同时表明要有效实施课程设计整合,需要加强质量评价体系和保证体系,才能真正强化实践教学效果,提高学生的学习能力和工程应用能力,实现高级应用型工程技术人才培养的目标要求。     

复杂网络在交通网络节点重要度评估中的应用

为了找到道路交通网络中的重要节点,保障交通通行.文中使用一种基于节点收缩方法的复杂网络节点重要度评估办法,将该方法应用于城市道路交通网络,并以莲湖区为例评估该区域城市道路交通网络的节点重要性.结果表明:道路交通网络中的节点重要度与通过该节点的交通流量和节点在网络中的位置有关,使用该方法得到了道路交通网络节点重要度的排序,结果更贴近实际情况.     

道路网匹配质量检核与修正机制研究

针对多源道路网匹配结果质量检核的问题,通过比较匹配道路节点及路段在形状、位置和拓扑等方面的特征相似度,提出了匹配结果的度量约束、拓扑关系约束以及一致性约束等概念,并据此构建了全局一致性测度函数.利用这些限制性约束条件对匹配结果进行质量评估,评估结果分为两类:质量可靠和质量不可靠.对于质量不可靠,需进一步交由人工判定,并以令全局一致性测度函数得到最快增长为目标,对匹配结果进行级联自动修正,直至全局一致性测度函数无法再增大为止.这种半自动的质量检核与修正机制能够对匹配结果进行快速的质量评定,消除误匹配和漏匹配,确保经修正的匹配结果相互兼容,满足全局一致性约束条件,从而改善数据质量.