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Investigation of Longitudinal Cracking in Widened Concrete Pavements 加宽混凝土路面纵向裂缝的研究
IF 1.1 4区 工程技术 Q4 ENGINEERING, CIVIL Pub Date : 2020-03-17 DOI: 10.7250/bjrbe.2020-15.468
Shuo Yang, Yang Zhang, O. Kaya, H. Ceylan, Sunghwan Kim
Widened slabs, widely employed in many US states in concrete pavements, have suffered from unexpected longitudinal cracks. These cracks suddenly appeared within 0.60 m to 1.20 m from widened slab edges and could be detrimental to the long-term pavement performance. The primary objective of this study was to identify possible causes for such longitudinal cracking observed on widened concrete pavements. Both field investigation and Finite Element Analysis were performed. Degrees of curling and warping were measured using a Terrestrial Laser Scanner. Concrete cores were also extracted to achieve a better understanding of how the cracking had developed. Field survey and numerical simulation results indicate that such longitudinal cracks could be primarily caused by a combination of excessive traffic loads, a high degree of curling and warping, inadequate support from underlying layers, pavement ageing, and skewed joints. It was also found that 4.30 m widened slabs coupled with tied Portland Cement Concrete shoulders outperformed others in terms of producing less cracking, even when they had experienced higher levels of truck traffic. The sites constructed in late afternoons also showed significantly less longitudinal cracks.
美国许多州广泛用于混凝土路面的加宽板出现了意想不到的纵向裂缝。这些裂缝突然出现在距离加宽板边缘0.60米至1.20米的范围内,可能对长期路面性能不利。本研究的主要目的是确定在加宽混凝土路面上观察到的这种纵向裂缝的可能原因。进行了现场调查和有限元分析。使用地面激光扫描仪测量卷曲和翘曲的程度。还提取了混凝土芯,以更好地了解裂缝是如何发展的。现场调查和数值模拟结果表明,此类纵向裂缝可能主要由过度的交通荷载、高度的卷曲和翘曲、下层支撑不足、路面老化和斜接缝共同造成。研究还发现,4.30米宽的板加上捆绑的波特兰水泥混凝土路肩,即使在卡车交通量较高的情况下,在产生较少裂缝方面也优于其他板。下午晚些时候建造的场地也显示出明显较少的纵向裂缝。
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引用次数: 8
Longitudinal Acceleration Models for Horizontal Reverse Curves of Two-Lane Rural Roads 双车道农村公路水平反向曲线的纵向加速度模型
IF 1.1 4区 工程技术 Q4 ENGINEERING, CIVIL Pub Date : 2020-03-17 DOI: 10.7250/bjrbe.2020-15.463
T. Echaveguren, Cristián Henríquez, Gustavo JIMÉNEZ-RAMOS
The operating speed profile models adopt acceleration and deceleration as constant values obtained from kinematic models, assuming that the operating speeds between two consecutive sections are not spatially correlated. Existent research shows that acceleration and deceleration in horizontal reverse curves (HRC) depend on the tangent length and curve radii. In this paper, accelerations/decelerations-geometry models for light cars are proposed. The models are based on the data obtained in-field with a 10 Hz GPS under favourable traffic, weather, and pavement condition to isolate the effect of road geometry over the speed changes. The models were calibrated using the 95th percentile of acceleration probability density function (pdf) obtained section to section in the HRC. It was found that the acceleration and deceleration pdf follow the Burr distribution. Therefore, a Box–Cox transformation is needed to properly calibrate acceleration-geometry models. The models obtained confirmed that accelerations and decelerations depend on the radius of entrance and departure curves of the HRC. The results contribute to better understanding of the acceleration/deceleration patterns of light cars and to enhancing operating speed models in the HRC.
运行速度剖面模型采用加速度和减速度作为从运动学模型获得的常数值,假设两个连续区段之间的运行速度在空间上不相关。已有研究表明,水平反向曲线的加速度和减速度取决于切线长度和曲线半径。本文提出了轻型汽车的加速/减速几何模型。该模型基于在有利的交通、天气和路面条件下使用10 Hz GPS在现场获得的数据,以隔离道路几何形状对速度变化的影响。使用HRC中逐段获得的加速度概率密度函数(pdf)的第95百分位对模型进行校准。研究发现,加速和减速pdf遵循伯尔分布。因此,需要进行Box–Cox变换来正确校准加速度几何模型。所获得的模型证实,加速度和减速取决于HRC的入口和出口曲线的半径。研究结果有助于更好地理解轻型汽车的加速/减速模式,并增强HRC中的运行速度模型。
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引用次数: 2
Vertical Dynamic Loads on Footbridges Generated by People Running 行人行走对人行天桥产生的垂直动荷载
IF 1.1 4区 工程技术 Q4 ENGINEERING, CIVIL Pub Date : 2020-03-17 DOI: 10.7250/bjrbe.2020-15.461
M. Pańtak
This paper concerns the issue of the dynamic impact of people running on footbridges with particular with attention to various footstrike patterns occurring during the running (i.e. heel strike pattern and forefoot strike pattern). The results of a series of laboratory tests of vertical ground reaction force (VGRF) measurements generated by running people are presented along with the characteristics of the VGRF curves. Based on the results of the tests, a new proposal for a dynamic load model generated by people classified as heel strike runners has been developed, and corrections of the input parameters of two load models proposed by other authors have been performed. Moreover, the VGRF modelling technique using the Gaussian functions is presented along with a set of equations describing the variability of the Gaussian function parameters as a function of the frequency of running. The presented methods of the VGRF modelling allow increasing the accuracy of determining the VGRF values and, consequently, increasing the accuracy of dynamic analyses of footbridges subjected to dynamic loads generated by people running.
本文研究了行人在人行天桥上行走时的动力冲击问题,特别关注了人在行走过程中出现的各种脚部撞击模式(即脚跟撞击模式和前脚部撞击模式)。本文介绍了一系列室内跑步人产生的垂直地面反力(VGRF)测量结果,以及VGRF曲线的特征。在试验结果的基础上,提出了一种新的由脚跟撞击跑步者产生的动态负荷模型,并对其他作者提出的两种负荷模型的输入参数进行了修正。此外,还提出了使用高斯函数的VGRF建模技术以及一组描述高斯函数参数随运行频率变化的方程。所提出的VGRF建模方法可以提高确定VGRF值的准确性,从而提高行人桥在人运行时产生的动荷载作用下的动力分析的准确性。
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引用次数: 2
Analysis of Older Pedestrian Accidents: A Case Study of Lithuania 老年行人交通事故分析:以立陶宛为例
IF 1.1 4区 工程技术 Q4 ENGINEERING, CIVIL Pub Date : 2020-03-17 DOI: 10.7250/bjrbe.2020-15.465
Vilma Jasiūnienė, D. Čygas
However, for several decades, Europe has been witnessing demographic ageing. As a result of these changes, a more significant number of elderly road users will be involved in future traffic, and therefore safe mobility management of the older will become an increasingly important issue. Various physical, sensory, and cognitive constraints affecting elderly road users lead to a rise in the likelihood of an accident, which, due to the increased physical vulnerability, cause more serious consequences of road accidents. The findings reported by the authors of an in-depth analysis of accidents for four years have demonstrated that the risk of road fatalities for elderly road users is by one fifth more significant than the average of all age groups, and the pedestrian plays the most critical role in road traffic. To adequately compensate for the observed age-related physiological changes, the authors discuss actions and road safety measures to ensure appropriate conditions for older pedestrians on the streets.
然而,几十年来,欧洲一直在见证人口老龄化。由于这些变化,更多的老年道路使用者将参与未来的交通,因此老年人的安全出行管理将成为一个越来越重要的问题。影响老年道路使用者的各种身体、感官和认知限制导致事故发生的可能性增加,由于身体脆弱性的增加,事故会导致更严重的道路事故后果。四年来对事故进行深入分析的作者报告的研究结果表明,老年道路使用者的道路死亡风险比所有年龄组的平均水平高出五分之一,行人在道路交通中发挥着最关键的作用。为了充分补偿观察到的与年龄相关的生理变化,作者讨论了行动和道路安全措施,以确保老年行人在街上有适当的条件。
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引用次数: 2
Damage Detection of Truss Structures by Reduction of Degrees of Freedom Using the Serep Method 用Serep方法降低自由度检测特拉斯结构的损伤
IF 1.1 4区 工程技术 Q4 ENGINEERING, CIVIL Pub Date : 2020-03-17 DOI: 10.7250/bjrbe.2020-15.459
Shahin Lale Arefi, A. Gholizad
Damage detection of bridge structures during their operating lifetime is essential. In this paper, two approaches, All Degrees of Freedom and Reduction of the Degrees of Freedom methods, are used to detect the damages in structures. The first method considers All Degrees of Freedom of the structure and the second method, Reduction of the Degrees of Freedom. Since the sensors are installed only on a few degrees of freedom, the responses are available for some of them. The Degrees of Freedom must be reduced and System Equivalent Reduction Expansion Process method is one of the most efficient ways to solve the problem. This research aimed to identify the damage of structures using the Modal Strain Energy method by reducing the structural degree of freedom. Two standard examples are used and the results compared to different damage cases to examine the efficiency of the mentioned method. The results illustrated the proper performance of the Reduction of the Degrees of Freedom method to identify the damage in truss structures. By increasing the number of modes, Reduction of the Degrees of Freedom method detects considerably more accurate the damaged elements, especially when the noise is considered. Also, based on the outcomes to identify damaged elements, it is possible to consider more modes instead of more sensors.
桥梁结构在使用寿命期间的损伤检测至关重要。本文采用全自由度法和自由度折减法两种方法对结构损伤进行检测。第一种方法考虑结构的所有自由度,第二种方法,自由度的减少。由于传感器只安装在几个自由度上,因此其中一些传感器的响应是可用的。自由度必须降阶,系统等效降阶展开法是解决这一问题的最有效方法之一。本研究旨在通过降低结构自由度,利用模态应变能方法识别结构的损伤。使用了两个标准示例,并将结果与不同的损伤情况进行了比较,以检验上述方法的有效性。结果表明,自由度折减法在特拉斯结构损伤识别中具有良好的性能。通过增加模式数量,减少自由度方法可以更准确地检测损坏的元件,尤其是在考虑噪声的情况下。此外,根据识别受损元件的结果,可以考虑更多的模式,而不是更多的传感器。
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引用次数: 2
The Interface Friction in The Friction-Type Bolted Joint of Steel Truss Bridge: Case Study 特拉斯钢桥摩擦型螺栓连接中的界面摩擦研究
IF 1.1 4区 工程技术 Q4 ENGINEERING, CIVIL Pub Date : 2020-03-17 DOI: 10.7250/bjrbe.2020-15.467
Gaoxin Wang, You-liang Ding
The friction-type bolted joint transfers the internal forces in the structural members by interface friction, but noticeable seasonal temperature and bolt fracture cause the redistribution of interface friction and threaten the joint safety. Therefore, this study carried out finite element analysis on the interface friction considering the influence of seasonal temperature and bolt fracture. Through finite element analysis, the simulation of interface friction under seasonal temperature revealed the distribution of temperature induced interface friction in different areas and locations. Further simulation of fractured bolts revealed the influence of quantity and location of fractured bolts on the redistribution of interface friction. Finally, the interface frictions in the bolted joint were evaluated using limit state equations. The results showed that: 1) the quantity and location of fractured bolts cause obvious redistribution of interface friction in the bolt-fractured areas; 2) the quantity and location of fractured bolts have slight effect on the total interface friction in the whole splice plate; 3) the reduced interface friction in the bolt-fractured areas was transferred to the areas without bolt fracture, producing little change in the total interface friction; 4) all the splice plates had abundant safety margin after analysis of their limit state equations.
摩擦型螺栓连接通过界面摩擦传递结构构件内部的内力,但明显的季节性温度和螺栓断裂导致界面摩擦的重新分布,威胁连接的安全。因此,本研究考虑季节性温度和螺栓断裂的影响,对界面摩擦进行了有限元分析。通过有限元分析,模拟了季节性温度下的界面摩擦,揭示了温度引起的界面摩擦在不同区域和位置的分布。对断裂螺栓的进一步模拟揭示了断裂螺栓的数量和位置对界面摩擦重新分布的影响。最后,使用极限状态方程对螺栓连接中的界面摩擦进行了评估。结果表明:1)断裂螺栓的数量和位置使界面摩擦力在螺栓断裂区明显再分配;2) 断裂螺栓的数量和位置对整个拼接板的总界面摩擦影响较小;3) 螺栓断裂区减小的界面摩擦力转移到未断裂区,总界面摩擦力变化不大;4) 通过对其极限状态方程的分析,所有拼接板都具有丰富的安全裕度。
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引用次数: 3
The Use of Bloss Curve in The Exit Lanes of Road Intersections 损失曲线在交叉口出口车道中的应用
IF 1.1 4区 工程技术 Q4 ENGINEERING, CIVIL Pub Date : 2020-03-17 DOI: 10.7250/bjrbe.2020-15.462
D. Ciampa, S. Olita
The paper proposes the use of the Bloss curve (also known as biparametric or bi-hyperclothoid) as a braking curve in the exit lanes of road intersections. The main international standards continue using the clohoid as the principal transitional geometric element, even though the limits of its use in driving regimes with non-uniform speeds are known. The proposal to use the Bloss curve is aimed at overcoming these limitations and opening a debate on the possible need to codify, even in the international standards, the use of more suitable alternative braking curves. In this context, a kinematic study was conducted by comparing the main parameters of the motion (lateral jerk, lateral acceleration, steering speed) between the Bloss curve and more traditional curves, such as clothoid and Generalized Cornu Spirals (GCS). Nine case studies were conducted, each case was characterized considering the type of transition curve used (clothoid, GCS and Bloss curve) and radius R of the exit curve (R = 60 m, 80 m, 100 m). The numerical values assumed by the kinematic variables along the transition curves were “locally” calculated, i.e. “pointby- point”, to take into account the non-uniform motion regime. The results obtained, limited to the cases studied, show that the Bloss curve better meets the kinematic conditions of the vehicle motion in non-uniform driving regimes. Therefore, the Bloss curve can be considered as a braking curve in the design of road intersections and be a candidate for further investigation to assess any additional benefits in terms of comfort, driving safety and visual perception of the geometric element.
本文提出了在道路交叉口出口车道使用blloss曲线(也称为双参数曲线或双超线曲线)作为制动曲线。主要的国际标准继续使用clocloid作为主要的过渡几何元素,尽管它在非均匀速度的驾驶制度中使用的限制是已知的。使用布洛斯曲线的建议旨在克服这些限制,并就可能需要编纂,甚至在国际标准中,使用更合适的替代制动曲线展开辩论。在此背景下,通过比较blloss曲线和更传统的曲线(如clodroid和Generalized Cornu Spirals, GCS)之间的运动主要参数(侧向加速度、侧向加速度、转向速度),进行了运动学研究。对9个案例进行了研究,每个案例都考虑了所使用的过渡曲线类型(clothoid, GCS和Bloss曲线)和出口曲线的半径R (R = 60 m, 80 m, 100 m)。考虑到非均匀运动状态,运动学变量沿过渡曲线的数值是“局部”计算的,即“逐点”计算。研究结果表明,在非均匀工况下,blloss曲线较好地满足了车辆运动的运动学条件。因此,可以将loss曲线视为道路交叉口设计中的制动曲线,并作为进一步研究的候选曲线,以评估几何元素在舒适性,驾驶安全性和视觉感知方面的任何额外好处。
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引用次数: 1
Experimental Method of Fatigue Performance of Mastic Asphalt for Bridge Deck Pavement 桥面铺装用沥青疲劳性能的试验方法
IF 1.1 4区 工程技术 Q4 ENGINEERING, CIVIL Pub Date : 2019-12-27 DOI: 10.7250/bjrbe.2019-14.458
G. Zou, Xiao-ning Zhang, C. Wu
Mastic asphalt is a type of pavement material that has good fluidity and is self-levelling at construction temperature for the bridge deck. There are highly accurate methods and indexes for evaluating fluidity and high-temperature deformation resistance for mastic asphalt-design and construction-control systems. The fatigue cracking is one of the main failure forms of bridge deck pavement. Therefore, the method used to evaluate the fatigue properties of pavement materials is also essential. The anti-deformation capability of the mastic asphalt must be increased, that results in poor fatigue performance and consequent failure of the bridge deck pavement to avoid the rutting of bridge deck pavement. In this study, a simple method is put forward for evaluating mastic asphalt fatigue performance.  Impact toughness is defined as the area under the load-displacement curve of a three-point bending beam specimen under impact load to evaluate the fatigue performance of mastic asphalt. The four-point bending beam fatigue test is used to verify the rationality of the impact toughness test method. The results showed that there is a good correlation between the impacts toughness index of mastic asphalt produced under different mixing conditions and the accumulative dissipative energy and fatigue life demonstrated by the four-point bending beam test. Therefore, to evaluate the fatigue performance of mastic asphalt by impact toughness test. Fatigue performance and rut resistance are two ways to evaluate road performance of asphalt mixtures, but they are mutually restrictive. The results show that impact toughness and dynamic stability are inversely correlated. As the impact toughness increases, dynamic stability decreases. Therefore, balancing the fatigue performance and high-temperature rutting resistance of mastic asphalt in the design and quality control is very important.
Mastic沥青是一种具有良好流动性的路面材料,在施工温度下可用于桥面自流平。对于沥青胶料的设计和施工控制系统,有非常准确的方法和指标来评估流动性和耐高温变形性。疲劳开裂是桥面铺装的主要失效形式之一。因此,用于评估路面材料疲劳性能的方法也是必不可少的。为了避免桥面铺装产生车辙,必须提高沥青玛蹄脂的抗变形能力,这会导致桥面铺装的疲劳性能较差,进而导致桥面铺装失效。在本研究中,提出了一种简单的方法来评估沥青胶浆的疲劳性能。冲击韧性定义为三点弯曲梁试样在冲击载荷下的载荷-位移曲线下的面积,以评估沥青胶的疲劳性能。采用四点弯曲梁疲劳试验验证了冲击韧性试验方法的合理性。结果表明,在不同搅拌条件下生产的玛蹄脂沥青的冲击韧性指数与四点弯曲梁试验显示的累积耗散能和疲劳寿命之间存在良好的相关性。因此,通过冲击韧性试验来评价沥青玛蹄脂的疲劳性能。疲劳性能和抗车辙性能是评价沥青混合料路用性能的两种方法,但它们相互制约。结果表明,冲击韧性与动态稳定性呈负相关。随着冲击韧性的增加,动态稳定性降低。因此,在设计和质量控制中,平衡胶浆沥青的疲劳性能和耐高温车辙性能是非常重要的。
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引用次数: 7
Parametric Analysis of Multi-Span Cable-Stayed Bridges Under Alternate Loads 多跨斜拉桥在交变荷载作用下的参数分析
IF 1.1 4区 工程技术 Q4 ENGINEERING, CIVIL Pub Date : 2019-12-27 DOI: 10.7250/bjrbe.2019-14.457
Hiram Arellano, R. Gómez, D. Tolentino
The influence of the stiffness of piers, pylons and deck in the behaviour of multi-span cable-stayed bridges under alternate live loads is analysed. The variation of these parameters is discussed considering both a harp cable system and a fan cable system. Different types of connections between pier-pylon and deck are also considered. Based on the behaviour of a three-span cable-stayed bridge, the variation of pier-pylon stiffness and deck stiffness was analysed. A similar state of stress and deflections was obtained for both a three-span and a multi-span cable-stayed bridge. The study shows that the harp type system presents advantages compared to fan type in terms of its behaviour under alternate live loads considering the same values of deck stiffness and pier-pylon stiffness. It is demonstrated that the resistant mechanism of multi-span cable- stayed bridges is provided by the pier-pylon element.
分析了墩、塔和桥面刚度对多跨斜拉桥在交变活载作用下性能的影响。考虑到竖琴电缆系统和风扇电缆系统,讨论了这些参数的变化。还考虑了桥墩塔架和甲板之间的不同类型的连接。根据一座三跨斜拉桥的受力特点,分析了桥墩-塔柱刚度和桥面刚度的变化规律。三跨和多跨斜拉桥的应力和挠度状态相似。研究表明,考虑到甲板刚度和桥塔刚度的相同值,与扇形系统相比,竖琴型系统在交变活载下的性能具有优势。研究表明,多跨斜拉桥的阻力机理是由墩-塔单元提供的。
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引用次数: 3
Effective Waterproofing of Railway Culvert Pipes 铁路涵管的有效防水
IF 1.1 4区 工程技术 Q4 ENGINEERING, CIVIL Pub Date : 2019-12-27 DOI: 10.7250/bjrbe.2019-14.453
L. Trykoz, S. Kamchatnaya, O. Pustovoitova, A. Atynian, O. Saiapin
The composition material for waterproofing of the railway infrastructure objects, in particular, culvert pipes is suggested in the article. The waterproof composition contains an acrylic polymer and a filler. The comparison of the composition properties with two kinds of the fillers (silica sand and Portland cement) is carried out. The following properties are defined – water absorption, corrosion stability, stability in an aggressive environment, frost resistance to evaluating the suitability of the proposed composition for waterproofing. These properties are determined for three batches: an acrylic polymer without a filler, an acrylic polymer with silica sand, and an acrylic polymer with Portland cement. The test results show that the composition with silica sand possesses the best waterproofing properties. Wherein the quantity of silica sand is 1.5 mass parts to the quantity of polymer. Compared to the non-filled acrylic polymer the offered composition is characterised less water absorption, more significant corrosion stability and stability in an aggressive environment, better frost resistance. The mix with Portland cement shows a bit worse results at a higher cost of the material in whole.
文章提出了铁路基础设施对象,特别是涵管防水的组成材料。该防水组合物包含丙烯酸聚合物和填料。对硅砂和硅酸盐水泥两种填料的组成性能进行了比较。定义了以下特性——吸水性、腐蚀稳定性、在侵蚀性环境中的稳定性、抗冻性,以评估拟议的防水组合物的适用性。这些性能是针对三个批次确定的:一种不含填料的丙烯酸聚合物,一种含硅砂的丙烯酸聚合物和一种含硅酸盐水泥的丙烯酸聚合物。试验结果表明,硅砂复合材料具有最佳的防水性能。其中,所述硅砂的量相对于聚合物的量为1.5质量份。与未填充的丙烯酸聚合物相比,所提供的组合物的特征是吸水性更小,在侵蚀性环境中具有更显著的腐蚀稳定性和稳定性,具有更好的抗冻性。与波特兰水泥的混合物在整体材料成本较高的情况下显示出更差的结果。
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引用次数: 6
期刊
Baltic Journal of Road and Bridge Engineering
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